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2332 lines
60 KiB
2332 lines
60 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* Virtio ring implementation. |
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* |
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* Copyright 2007 Rusty Russell IBM Corporation |
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*/ |
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#include <linux/virtio.h> |
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#include <linux/virtio_ring.h> |
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#include <linux/virtio_config.h> |
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#include <linux/device.h> |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#include <linux/hrtimer.h> |
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#include <linux/dma-mapping.h> |
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#include <xen/xen.h> |
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|
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#ifdef DEBUG |
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/* For development, we want to crash whenever the ring is screwed. */ |
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#define BAD_RING(_vq, fmt, args...) \ |
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do { \ |
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dev_err(&(_vq)->vq.vdev->dev, \ |
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"%s:"fmt, (_vq)->vq.name, ##args); \ |
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BUG(); \ |
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} while (0) |
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/* Caller is supposed to guarantee no reentry. */ |
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#define START_USE(_vq) \ |
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do { \ |
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if ((_vq)->in_use) \ |
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panic("%s:in_use = %i\n", \ |
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(_vq)->vq.name, (_vq)->in_use); \ |
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(_vq)->in_use = __LINE__; \ |
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} while (0) |
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#define END_USE(_vq) \ |
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do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0) |
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#define LAST_ADD_TIME_UPDATE(_vq) \ |
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do { \ |
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ktime_t now = ktime_get(); \ |
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\ |
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/* No kick or get, with .1 second between? Warn. */ \ |
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if ((_vq)->last_add_time_valid) \ |
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WARN_ON(ktime_to_ms(ktime_sub(now, \ |
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(_vq)->last_add_time)) > 100); \ |
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(_vq)->last_add_time = now; \ |
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(_vq)->last_add_time_valid = true; \ |
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} while (0) |
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#define LAST_ADD_TIME_CHECK(_vq) \ |
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do { \ |
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if ((_vq)->last_add_time_valid) { \ |
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WARN_ON(ktime_to_ms(ktime_sub(ktime_get(), \ |
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(_vq)->last_add_time)) > 100); \ |
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} \ |
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} while (0) |
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#define LAST_ADD_TIME_INVALID(_vq) \ |
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((_vq)->last_add_time_valid = false) |
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#else |
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#define BAD_RING(_vq, fmt, args...) \ |
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do { \ |
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dev_err(&_vq->vq.vdev->dev, \ |
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"%s:"fmt, (_vq)->vq.name, ##args); \ |
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(_vq)->broken = true; \ |
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} while (0) |
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#define START_USE(vq) |
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#define END_USE(vq) |
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#define LAST_ADD_TIME_UPDATE(vq) |
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#define LAST_ADD_TIME_CHECK(vq) |
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#define LAST_ADD_TIME_INVALID(vq) |
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#endif |
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|
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struct vring_desc_state_split { |
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void *data; /* Data for callback. */ |
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struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ |
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}; |
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|
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struct vring_desc_state_packed { |
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void *data; /* Data for callback. */ |
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struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */ |
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u16 num; /* Descriptor list length. */ |
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u16 next; /* The next desc state in a list. */ |
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u16 last; /* The last desc state in a list. */ |
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}; |
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|
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struct vring_desc_extra_packed { |
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dma_addr_t addr; /* Buffer DMA addr. */ |
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u32 len; /* Buffer length. */ |
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u16 flags; /* Descriptor flags. */ |
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}; |
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|
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struct vring_virtqueue { |
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struct virtqueue vq; |
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|
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/* Is this a packed ring? */ |
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bool packed_ring; |
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|
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/* Is DMA API used? */ |
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bool use_dma_api; |
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|
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/* Can we use weak barriers? */ |
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bool weak_barriers; |
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|
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/* Other side has made a mess, don't try any more. */ |
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bool broken; |
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|
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/* Host supports indirect buffers */ |
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bool indirect; |
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|
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/* Host publishes avail event idx */ |
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bool event; |
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|
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/* Head of free buffer list. */ |
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unsigned int free_head; |
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/* Number we've added since last sync. */ |
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unsigned int num_added; |
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|
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/* Last used index we've seen. */ |
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u16 last_used_idx; |
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|
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union { |
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/* Available for split ring */ |
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struct { |
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/* Actual memory layout for this queue. */ |
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struct vring vring; |
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|
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/* Last written value to avail->flags */ |
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u16 avail_flags_shadow; |
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|
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/* |
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* Last written value to avail->idx in |
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* guest byte order. |
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*/ |
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u16 avail_idx_shadow; |
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|
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/* Per-descriptor state. */ |
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struct vring_desc_state_split *desc_state; |
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|
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/* DMA address and size information */ |
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dma_addr_t queue_dma_addr; |
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size_t queue_size_in_bytes; |
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} split; |
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|
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/* Available for packed ring */ |
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struct { |
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/* Actual memory layout for this queue. */ |
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struct { |
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unsigned int num; |
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struct vring_packed_desc *desc; |
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struct vring_packed_desc_event *driver; |
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struct vring_packed_desc_event *device; |
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} vring; |
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|
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/* Driver ring wrap counter. */ |
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bool avail_wrap_counter; |
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|
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/* Device ring wrap counter. */ |
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bool used_wrap_counter; |
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|
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/* Avail used flags. */ |
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u16 avail_used_flags; |
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|
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/* Index of the next avail descriptor. */ |
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u16 next_avail_idx; |
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|
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/* |
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* Last written value to driver->flags in |
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* guest byte order. |
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*/ |
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u16 event_flags_shadow; |
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|
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/* Per-descriptor state. */ |
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struct vring_desc_state_packed *desc_state; |
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struct vring_desc_extra_packed *desc_extra; |
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|
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/* DMA address and size information */ |
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dma_addr_t ring_dma_addr; |
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dma_addr_t driver_event_dma_addr; |
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dma_addr_t device_event_dma_addr; |
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size_t ring_size_in_bytes; |
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size_t event_size_in_bytes; |
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} packed; |
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}; |
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|
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/* How to notify other side. FIXME: commonalize hcalls! */ |
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bool (*notify)(struct virtqueue *vq); |
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|
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/* DMA, allocation, and size information */ |
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bool we_own_ring; |
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|
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#ifdef DEBUG |
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/* They're supposed to lock for us. */ |
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unsigned int in_use; |
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|
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/* Figure out if their kicks are too delayed. */ |
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bool last_add_time_valid; |
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ktime_t last_add_time; |
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#endif |
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}; |
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|
|
|
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/* |
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* Helpers. |
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*/ |
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|
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#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq) |
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|
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static inline bool virtqueue_use_indirect(struct virtqueue *_vq, |
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unsigned int total_sg) |
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{ |
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struct vring_virtqueue *vq = to_vvq(_vq); |
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|
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/* |
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* If the host supports indirect descriptor tables, and we have multiple |
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* buffers, then go indirect. FIXME: tune this threshold |
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*/ |
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return (vq->indirect && total_sg > 1 && vq->vq.num_free); |
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} |
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|
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/* |
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* Modern virtio devices have feature bits to specify whether they need a |
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* quirk and bypass the IOMMU. If not there, just use the DMA API. |
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* |
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* If there, the interaction between virtio and DMA API is messy. |
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* |
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* On most systems with virtio, physical addresses match bus addresses, |
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* and it doesn't particularly matter whether we use the DMA API. |
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* |
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* On some systems, including Xen and any system with a physical device |
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* that speaks virtio behind a physical IOMMU, we must use the DMA API |
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* for virtio DMA to work at all. |
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* |
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* On other systems, including SPARC and PPC64, virtio-pci devices are |
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* enumerated as though they are behind an IOMMU, but the virtio host |
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* ignores the IOMMU, so we must either pretend that the IOMMU isn't |
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* there or somehow map everything as the identity. |
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* |
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* For the time being, we preserve historic behavior and bypass the DMA |
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* API. |
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* |
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* TODO: install a per-device DMA ops structure that does the right thing |
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* taking into account all the above quirks, and use the DMA API |
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* unconditionally on data path. |
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*/ |
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|
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static bool vring_use_dma_api(struct virtio_device *vdev) |
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{ |
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if (!virtio_has_dma_quirk(vdev)) |
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return true; |
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|
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/* Otherwise, we are left to guess. */ |
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/* |
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* In theory, it's possible to have a buggy QEMU-supposed |
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* emulated Q35 IOMMU and Xen enabled at the same time. On |
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* such a configuration, virtio has never worked and will |
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* not work without an even larger kludge. Instead, enable |
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* the DMA API if we're a Xen guest, which at least allows |
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* all of the sensible Xen configurations to work correctly. |
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*/ |
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if (xen_domain()) |
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return true; |
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|
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return false; |
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} |
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|
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size_t virtio_max_dma_size(struct virtio_device *vdev) |
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{ |
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size_t max_segment_size = SIZE_MAX; |
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|
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if (vring_use_dma_api(vdev)) |
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max_segment_size = dma_max_mapping_size(&vdev->dev); |
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return max_segment_size; |
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} |
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EXPORT_SYMBOL_GPL(virtio_max_dma_size); |
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|
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static void *vring_alloc_queue(struct virtio_device *vdev, size_t size, |
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dma_addr_t *dma_handle, gfp_t flag) |
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{ |
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if (vring_use_dma_api(vdev)) { |
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return dma_alloc_coherent(vdev->dev.parent, size, |
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dma_handle, flag); |
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} else { |
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void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag); |
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|
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if (queue) { |
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phys_addr_t phys_addr = virt_to_phys(queue); |
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*dma_handle = (dma_addr_t)phys_addr; |
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|
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/* |
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* Sanity check: make sure we dind't truncate |
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* the address. The only arches I can find that |
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* have 64-bit phys_addr_t but 32-bit dma_addr_t |
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* are certain non-highmem MIPS and x86 |
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* configurations, but these configurations |
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* should never allocate physical pages above 32 |
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* bits, so this is fine. Just in case, throw a |
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* warning and abort if we end up with an |
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* unrepresentable address. |
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*/ |
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if (WARN_ON_ONCE(*dma_handle != phys_addr)) { |
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free_pages_exact(queue, PAGE_ALIGN(size)); |
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return NULL; |
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} |
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} |
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return queue; |
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} |
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} |
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static void vring_free_queue(struct virtio_device *vdev, size_t size, |
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void *queue, dma_addr_t dma_handle) |
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{ |
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if (vring_use_dma_api(vdev)) |
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dma_free_coherent(vdev->dev.parent, size, queue, dma_handle); |
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else |
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free_pages_exact(queue, PAGE_ALIGN(size)); |
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} |
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|
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/* |
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* The DMA ops on various arches are rather gnarly right now, and |
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* making all of the arch DMA ops work on the vring device itself |
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* is a mess. For now, we use the parent device for DMA ops. |
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*/ |
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static inline struct device *vring_dma_dev(const struct vring_virtqueue *vq) |
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{ |
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return vq->vq.vdev->dev.parent; |
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} |
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|
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/* Map one sg entry. */ |
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static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq, |
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struct scatterlist *sg, |
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enum dma_data_direction direction) |
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{ |
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if (!vq->use_dma_api) |
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return (dma_addr_t)sg_phys(sg); |
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|
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/* |
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* We can't use dma_map_sg, because we don't use scatterlists in |
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* the way it expects (we don't guarantee that the scatterlist |
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* will exist for the lifetime of the mapping). |
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*/ |
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return dma_map_page(vring_dma_dev(vq), |
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sg_page(sg), sg->offset, sg->length, |
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direction); |
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} |
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|
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static dma_addr_t vring_map_single(const struct vring_virtqueue *vq, |
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void *cpu_addr, size_t size, |
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enum dma_data_direction direction) |
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{ |
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if (!vq->use_dma_api) |
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return (dma_addr_t)virt_to_phys(cpu_addr); |
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|
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return dma_map_single(vring_dma_dev(vq), |
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cpu_addr, size, direction); |
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} |
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|
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static int vring_mapping_error(const struct vring_virtqueue *vq, |
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dma_addr_t addr) |
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{ |
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if (!vq->use_dma_api) |
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return 0; |
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|
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return dma_mapping_error(vring_dma_dev(vq), addr); |
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} |
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|
|
|
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/* |
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* Split ring specific functions - *_split(). |
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*/ |
|
|
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static void vring_unmap_one_split(const struct vring_virtqueue *vq, |
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struct vring_desc *desc) |
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{ |
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u16 flags; |
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|
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if (!vq->use_dma_api) |
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return; |
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|
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flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); |
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|
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if (flags & VRING_DESC_F_INDIRECT) { |
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dma_unmap_single(vring_dma_dev(vq), |
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virtio64_to_cpu(vq->vq.vdev, desc->addr), |
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virtio32_to_cpu(vq->vq.vdev, desc->len), |
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(flags & VRING_DESC_F_WRITE) ? |
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DMA_FROM_DEVICE : DMA_TO_DEVICE); |
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} else { |
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dma_unmap_page(vring_dma_dev(vq), |
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virtio64_to_cpu(vq->vq.vdev, desc->addr), |
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virtio32_to_cpu(vq->vq.vdev, desc->len), |
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(flags & VRING_DESC_F_WRITE) ? |
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DMA_FROM_DEVICE : DMA_TO_DEVICE); |
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} |
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} |
|
|
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static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, |
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unsigned int total_sg, |
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gfp_t gfp) |
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{ |
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struct vring_desc *desc; |
|
unsigned int i; |
|
|
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/* |
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* We require lowmem mappings for the descriptors because |
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* otherwise virt_to_phys will give us bogus addresses in the |
|
* virtqueue. |
|
*/ |
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gfp &= ~__GFP_HIGHMEM; |
|
|
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desc = kmalloc_array(total_sg, sizeof(struct vring_desc), gfp); |
|
if (!desc) |
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return NULL; |
|
|
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for (i = 0; i < total_sg; i++) |
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desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1); |
|
return desc; |
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} |
|
|
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static inline int virtqueue_add_split(struct virtqueue *_vq, |
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struct scatterlist *sgs[], |
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unsigned int total_sg, |
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unsigned int out_sgs, |
|
unsigned int in_sgs, |
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void *data, |
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void *ctx, |
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gfp_t gfp) |
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{ |
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struct vring_virtqueue *vq = to_vvq(_vq); |
|
struct scatterlist *sg; |
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struct vring_desc *desc; |
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unsigned int i, n, avail, descs_used, prev, err_idx; |
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int head; |
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bool indirect; |
|
|
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START_USE(vq); |
|
|
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BUG_ON(data == NULL); |
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BUG_ON(ctx && vq->indirect); |
|
|
|
if (unlikely(vq->broken)) { |
|
END_USE(vq); |
|
return -EIO; |
|
} |
|
|
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LAST_ADD_TIME_UPDATE(vq); |
|
|
|
BUG_ON(total_sg == 0); |
|
|
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head = vq->free_head; |
|
|
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if (virtqueue_use_indirect(_vq, total_sg)) |
|
desc = alloc_indirect_split(_vq, total_sg, gfp); |
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else { |
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desc = NULL; |
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WARN_ON_ONCE(total_sg > vq->split.vring.num && !vq->indirect); |
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} |
|
|
|
if (desc) { |
|
/* Use a single buffer which doesn't continue */ |
|
indirect = true; |
|
/* Set up rest to use this indirect table. */ |
|
i = 0; |
|
descs_used = 1; |
|
} else { |
|
indirect = false; |
|
desc = vq->split.vring.desc; |
|
i = head; |
|
descs_used = total_sg; |
|
} |
|
|
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if (vq->vq.num_free < descs_used) { |
|
pr_debug("Can't add buf len %i - avail = %i\n", |
|
descs_used, vq->vq.num_free); |
|
/* FIXME: for historical reasons, we force a notify here if |
|
* there are outgoing parts to the buffer. Presumably the |
|
* host should service the ring ASAP. */ |
|
if (out_sgs) |
|
vq->notify(&vq->vq); |
|
if (indirect) |
|
kfree(desc); |
|
END_USE(vq); |
|
return -ENOSPC; |
|
} |
|
|
|
for (n = 0; n < out_sgs; n++) { |
|
for (sg = sgs[n]; sg; sg = sg_next(sg)) { |
|
dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); |
|
if (vring_mapping_error(vq, addr)) |
|
goto unmap_release; |
|
|
|
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT); |
|
desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); |
|
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); |
|
prev = i; |
|
i = virtio16_to_cpu(_vq->vdev, desc[i].next); |
|
} |
|
} |
|
for (; n < (out_sgs + in_sgs); n++) { |
|
for (sg = sgs[n]; sg; sg = sg_next(sg)) { |
|
dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); |
|
if (vring_mapping_error(vq, addr)) |
|
goto unmap_release; |
|
|
|
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE); |
|
desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); |
|
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); |
|
prev = i; |
|
i = virtio16_to_cpu(_vq->vdev, desc[i].next); |
|
} |
|
} |
|
/* Last one doesn't continue. */ |
|
desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); |
|
|
|
if (indirect) { |
|
/* Now that the indirect table is filled in, map it. */ |
|
dma_addr_t addr = vring_map_single( |
|
vq, desc, total_sg * sizeof(struct vring_desc), |
|
DMA_TO_DEVICE); |
|
if (vring_mapping_error(vq, addr)) |
|
goto unmap_release; |
|
|
|
vq->split.vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, |
|
VRING_DESC_F_INDIRECT); |
|
vq->split.vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, |
|
addr); |
|
|
|
vq->split.vring.desc[head].len = cpu_to_virtio32(_vq->vdev, |
|
total_sg * sizeof(struct vring_desc)); |
|
} |
|
|
|
/* We're using some buffers from the free list. */ |
|
vq->vq.num_free -= descs_used; |
|
|
|
/* Update free pointer */ |
|
if (indirect) |
|
vq->free_head = virtio16_to_cpu(_vq->vdev, |
|
vq->split.vring.desc[head].next); |
|
else |
|
vq->free_head = i; |
|
|
|
/* Store token and indirect buffer state. */ |
|
vq->split.desc_state[head].data = data; |
|
if (indirect) |
|
vq->split.desc_state[head].indir_desc = desc; |
|
else |
|
vq->split.desc_state[head].indir_desc = ctx; |
|
|
|
/* Put entry in available array (but don't update avail->idx until they |
|
* do sync). */ |
|
avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1); |
|
vq->split.vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head); |
|
|
|
/* Descriptors and available array need to be set before we expose the |
|
* new available array entries. */ |
|
virtio_wmb(vq->weak_barriers); |
|
vq->split.avail_idx_shadow++; |
|
vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, |
|
vq->split.avail_idx_shadow); |
|
vq->num_added++; |
|
|
|
pr_debug("Added buffer head %i to %p\n", head, vq); |
|
END_USE(vq); |
|
|
|
/* This is very unlikely, but theoretically possible. Kick |
|
* just in case. */ |
|
if (unlikely(vq->num_added == (1 << 16) - 1)) |
|
virtqueue_kick(_vq); |
|
|
|
return 0; |
|
|
|
unmap_release: |
|
err_idx = i; |
|
|
|
if (indirect) |
|
i = 0; |
|
else |
|
i = head; |
|
|
|
for (n = 0; n < total_sg; n++) { |
|
if (i == err_idx) |
|
break; |
|
vring_unmap_one_split(vq, &desc[i]); |
|
i = virtio16_to_cpu(_vq->vdev, desc[i].next); |
|
} |
|
|
|
if (indirect) |
|
kfree(desc); |
|
|
|
END_USE(vq); |
|
return -ENOMEM; |
|
} |
|
|
|
static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
u16 new, old; |
|
bool needs_kick; |
|
|
|
START_USE(vq); |
|
/* We need to expose available array entries before checking avail |
|
* event. */ |
|
virtio_mb(vq->weak_barriers); |
|
|
|
old = vq->split.avail_idx_shadow - vq->num_added; |
|
new = vq->split.avail_idx_shadow; |
|
vq->num_added = 0; |
|
|
|
LAST_ADD_TIME_CHECK(vq); |
|
LAST_ADD_TIME_INVALID(vq); |
|
|
|
if (vq->event) { |
|
needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, |
|
vring_avail_event(&vq->split.vring)), |
|
new, old); |
|
} else { |
|
needs_kick = !(vq->split.vring.used->flags & |
|
cpu_to_virtio16(_vq->vdev, |
|
VRING_USED_F_NO_NOTIFY)); |
|
} |
|
END_USE(vq); |
|
return needs_kick; |
|
} |
|
|
|
static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, |
|
void **ctx) |
|
{ |
|
unsigned int i, j; |
|
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); |
|
|
|
/* Clear data ptr. */ |
|
vq->split.desc_state[head].data = NULL; |
|
|
|
/* Put back on free list: unmap first-level descriptors and find end */ |
|
i = head; |
|
|
|
while (vq->split.vring.desc[i].flags & nextflag) { |
|
vring_unmap_one_split(vq, &vq->split.vring.desc[i]); |
|
i = virtio16_to_cpu(vq->vq.vdev, vq->split.vring.desc[i].next); |
|
vq->vq.num_free++; |
|
} |
|
|
|
vring_unmap_one_split(vq, &vq->split.vring.desc[i]); |
|
vq->split.vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, |
|
vq->free_head); |
|
vq->free_head = head; |
|
|
|
/* Plus final descriptor */ |
|
vq->vq.num_free++; |
|
|
|
if (vq->indirect) { |
|
struct vring_desc *indir_desc = |
|
vq->split.desc_state[head].indir_desc; |
|
u32 len; |
|
|
|
/* Free the indirect table, if any, now that it's unmapped. */ |
|
if (!indir_desc) |
|
return; |
|
|
|
len = virtio32_to_cpu(vq->vq.vdev, |
|
vq->split.vring.desc[head].len); |
|
|
|
BUG_ON(!(vq->split.vring.desc[head].flags & |
|
cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))); |
|
BUG_ON(len == 0 || len % sizeof(struct vring_desc)); |
|
|
|
for (j = 0; j < len / sizeof(struct vring_desc); j++) |
|
vring_unmap_one_split(vq, &indir_desc[j]); |
|
|
|
kfree(indir_desc); |
|
vq->split.desc_state[head].indir_desc = NULL; |
|
} else if (ctx) { |
|
*ctx = vq->split.desc_state[head].indir_desc; |
|
} |
|
} |
|
|
|
static inline bool more_used_split(const struct vring_virtqueue *vq) |
|
{ |
|
return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, |
|
vq->split.vring.used->idx); |
|
} |
|
|
|
static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq, |
|
unsigned int *len, |
|
void **ctx) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
void *ret; |
|
unsigned int i; |
|
u16 last_used; |
|
|
|
START_USE(vq); |
|
|
|
if (unlikely(vq->broken)) { |
|
END_USE(vq); |
|
return NULL; |
|
} |
|
|
|
if (!more_used_split(vq)) { |
|
pr_debug("No more buffers in queue\n"); |
|
END_USE(vq); |
|
return NULL; |
|
} |
|
|
|
/* Only get used array entries after they have been exposed by host. */ |
|
virtio_rmb(vq->weak_barriers); |
|
|
|
last_used = (vq->last_used_idx & (vq->split.vring.num - 1)); |
|
i = virtio32_to_cpu(_vq->vdev, |
|
vq->split.vring.used->ring[last_used].id); |
|
*len = virtio32_to_cpu(_vq->vdev, |
|
vq->split.vring.used->ring[last_used].len); |
|
|
|
if (unlikely(i >= vq->split.vring.num)) { |
|
BAD_RING(vq, "id %u out of range\n", i); |
|
return NULL; |
|
} |
|
if (unlikely(!vq->split.desc_state[i].data)) { |
|
BAD_RING(vq, "id %u is not a head!\n", i); |
|
return NULL; |
|
} |
|
|
|
/* detach_buf_split clears data, so grab it now. */ |
|
ret = vq->split.desc_state[i].data; |
|
detach_buf_split(vq, i, ctx); |
|
vq->last_used_idx++; |
|
/* If we expect an interrupt for the next entry, tell host |
|
* by writing event index and flush out the write before |
|
* the read in the next get_buf call. */ |
|
if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) |
|
virtio_store_mb(vq->weak_barriers, |
|
&vring_used_event(&vq->split.vring), |
|
cpu_to_virtio16(_vq->vdev, vq->last_used_idx)); |
|
|
|
LAST_ADD_TIME_INVALID(vq); |
|
|
|
END_USE(vq); |
|
return ret; |
|
} |
|
|
|
static void virtqueue_disable_cb_split(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) { |
|
vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; |
|
if (!vq->event) |
|
vq->split.vring.avail->flags = |
|
cpu_to_virtio16(_vq->vdev, |
|
vq->split.avail_flags_shadow); |
|
} |
|
} |
|
|
|
static unsigned virtqueue_enable_cb_prepare_split(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
u16 last_used_idx; |
|
|
|
START_USE(vq); |
|
|
|
/* We optimistically turn back on interrupts, then check if there was |
|
* more to do. */ |
|
/* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to |
|
* either clear the flags bit or point the event index at the next |
|
* entry. Always do both to keep code simple. */ |
|
if (vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) { |
|
vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT; |
|
if (!vq->event) |
|
vq->split.vring.avail->flags = |
|
cpu_to_virtio16(_vq->vdev, |
|
vq->split.avail_flags_shadow); |
|
} |
|
vring_used_event(&vq->split.vring) = cpu_to_virtio16(_vq->vdev, |
|
last_used_idx = vq->last_used_idx); |
|
END_USE(vq); |
|
return last_used_idx; |
|
} |
|
|
|
static bool virtqueue_poll_split(struct virtqueue *_vq, unsigned last_used_idx) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, |
|
vq->split.vring.used->idx); |
|
} |
|
|
|
static bool virtqueue_enable_cb_delayed_split(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
u16 bufs; |
|
|
|
START_USE(vq); |
|
|
|
/* We optimistically turn back on interrupts, then check if there was |
|
* more to do. */ |
|
/* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to |
|
* either clear the flags bit or point the event index at the next |
|
* entry. Always update the event index to keep code simple. */ |
|
if (vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) { |
|
vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT; |
|
if (!vq->event) |
|
vq->split.vring.avail->flags = |
|
cpu_to_virtio16(_vq->vdev, |
|
vq->split.avail_flags_shadow); |
|
} |
|
/* TODO: tune this threshold */ |
|
bufs = (u16)(vq->split.avail_idx_shadow - vq->last_used_idx) * 3 / 4; |
|
|
|
virtio_store_mb(vq->weak_barriers, |
|
&vring_used_event(&vq->split.vring), |
|
cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs)); |
|
|
|
if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->split.vring.used->idx) |
|
- vq->last_used_idx) > bufs)) { |
|
END_USE(vq); |
|
return false; |
|
} |
|
|
|
END_USE(vq); |
|
return true; |
|
} |
|
|
|
static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
unsigned int i; |
|
void *buf; |
|
|
|
START_USE(vq); |
|
|
|
for (i = 0; i < vq->split.vring.num; i++) { |
|
if (!vq->split.desc_state[i].data) |
|
continue; |
|
/* detach_buf_split clears data, so grab it now. */ |
|
buf = vq->split.desc_state[i].data; |
|
detach_buf_split(vq, i, NULL); |
|
vq->split.avail_idx_shadow--; |
|
vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev, |
|
vq->split.avail_idx_shadow); |
|
END_USE(vq); |
|
return buf; |
|
} |
|
/* That should have freed everything. */ |
|
BUG_ON(vq->vq.num_free != vq->split.vring.num); |
|
|
|
END_USE(vq); |
|
return NULL; |
|
} |
|
|
|
static struct virtqueue *vring_create_virtqueue_split( |
|
unsigned int index, |
|
unsigned int num, |
|
unsigned int vring_align, |
|
struct virtio_device *vdev, |
|
bool weak_barriers, |
|
bool may_reduce_num, |
|
bool context, |
|
bool (*notify)(struct virtqueue *), |
|
void (*callback)(struct virtqueue *), |
|
const char *name) |
|
{ |
|
struct virtqueue *vq; |
|
void *queue = NULL; |
|
dma_addr_t dma_addr; |
|
size_t queue_size_in_bytes; |
|
struct vring vring; |
|
|
|
/* We assume num is a power of 2. */ |
|
if (num & (num - 1)) { |
|
dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num); |
|
return NULL; |
|
} |
|
|
|
/* TODO: allocate each queue chunk individually */ |
|
for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) { |
|
queue = vring_alloc_queue(vdev, vring_size(num, vring_align), |
|
&dma_addr, |
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); |
|
if (queue) |
|
break; |
|
if (!may_reduce_num) |
|
return NULL; |
|
} |
|
|
|
if (!num) |
|
return NULL; |
|
|
|
if (!queue) { |
|
/* Try to get a single page. You are my only hope! */ |
|
queue = vring_alloc_queue(vdev, vring_size(num, vring_align), |
|
&dma_addr, GFP_KERNEL|__GFP_ZERO); |
|
} |
|
if (!queue) |
|
return NULL; |
|
|
|
queue_size_in_bytes = vring_size(num, vring_align); |
|
vring_init(&vring, num, queue, vring_align); |
|
|
|
vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context, |
|
notify, callback, name); |
|
if (!vq) { |
|
vring_free_queue(vdev, queue_size_in_bytes, queue, |
|
dma_addr); |
|
return NULL; |
|
} |
|
|
|
to_vvq(vq)->split.queue_dma_addr = dma_addr; |
|
to_vvq(vq)->split.queue_size_in_bytes = queue_size_in_bytes; |
|
to_vvq(vq)->we_own_ring = true; |
|
|
|
return vq; |
|
} |
|
|
|
|
|
/* |
|
* Packed ring specific functions - *_packed(). |
|
*/ |
|
|
|
static void vring_unmap_state_packed(const struct vring_virtqueue *vq, |
|
struct vring_desc_extra_packed *state) |
|
{ |
|
u16 flags; |
|
|
|
if (!vq->use_dma_api) |
|
return; |
|
|
|
flags = state->flags; |
|
|
|
if (flags & VRING_DESC_F_INDIRECT) { |
|
dma_unmap_single(vring_dma_dev(vq), |
|
state->addr, state->len, |
|
(flags & VRING_DESC_F_WRITE) ? |
|
DMA_FROM_DEVICE : DMA_TO_DEVICE); |
|
} else { |
|
dma_unmap_page(vring_dma_dev(vq), |
|
state->addr, state->len, |
|
(flags & VRING_DESC_F_WRITE) ? |
|
DMA_FROM_DEVICE : DMA_TO_DEVICE); |
|
} |
|
} |
|
|
|
static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, |
|
struct vring_packed_desc *desc) |
|
{ |
|
u16 flags; |
|
|
|
if (!vq->use_dma_api) |
|
return; |
|
|
|
flags = le16_to_cpu(desc->flags); |
|
|
|
if (flags & VRING_DESC_F_INDIRECT) { |
|
dma_unmap_single(vring_dma_dev(vq), |
|
le64_to_cpu(desc->addr), |
|
le32_to_cpu(desc->len), |
|
(flags & VRING_DESC_F_WRITE) ? |
|
DMA_FROM_DEVICE : DMA_TO_DEVICE); |
|
} else { |
|
dma_unmap_page(vring_dma_dev(vq), |
|
le64_to_cpu(desc->addr), |
|
le32_to_cpu(desc->len), |
|
(flags & VRING_DESC_F_WRITE) ? |
|
DMA_FROM_DEVICE : DMA_TO_DEVICE); |
|
} |
|
} |
|
|
|
static struct vring_packed_desc *alloc_indirect_packed(unsigned int total_sg, |
|
gfp_t gfp) |
|
{ |
|
struct vring_packed_desc *desc; |
|
|
|
/* |
|
* We require lowmem mappings for the descriptors because |
|
* otherwise virt_to_phys will give us bogus addresses in the |
|
* virtqueue. |
|
*/ |
|
gfp &= ~__GFP_HIGHMEM; |
|
|
|
desc = kmalloc_array(total_sg, sizeof(struct vring_packed_desc), gfp); |
|
|
|
return desc; |
|
} |
|
|
|
static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, |
|
struct scatterlist *sgs[], |
|
unsigned int total_sg, |
|
unsigned int out_sgs, |
|
unsigned int in_sgs, |
|
void *data, |
|
gfp_t gfp) |
|
{ |
|
struct vring_packed_desc *desc; |
|
struct scatterlist *sg; |
|
unsigned int i, n, err_idx; |
|
u16 head, id; |
|
dma_addr_t addr; |
|
|
|
head = vq->packed.next_avail_idx; |
|
desc = alloc_indirect_packed(total_sg, gfp); |
|
|
|
if (unlikely(vq->vq.num_free < 1)) { |
|
pr_debug("Can't add buf len 1 - avail = 0\n"); |
|
kfree(desc); |
|
END_USE(vq); |
|
return -ENOSPC; |
|
} |
|
|
|
i = 0; |
|
id = vq->free_head; |
|
BUG_ON(id == vq->packed.vring.num); |
|
|
|
for (n = 0; n < out_sgs + in_sgs; n++) { |
|
for (sg = sgs[n]; sg; sg = sg_next(sg)) { |
|
addr = vring_map_one_sg(vq, sg, n < out_sgs ? |
|
DMA_TO_DEVICE : DMA_FROM_DEVICE); |
|
if (vring_mapping_error(vq, addr)) |
|
goto unmap_release; |
|
|
|
desc[i].flags = cpu_to_le16(n < out_sgs ? |
|
0 : VRING_DESC_F_WRITE); |
|
desc[i].addr = cpu_to_le64(addr); |
|
desc[i].len = cpu_to_le32(sg->length); |
|
i++; |
|
} |
|
} |
|
|
|
/* Now that the indirect table is filled in, map it. */ |
|
addr = vring_map_single(vq, desc, |
|
total_sg * sizeof(struct vring_packed_desc), |
|
DMA_TO_DEVICE); |
|
if (vring_mapping_error(vq, addr)) |
|
goto unmap_release; |
|
|
|
vq->packed.vring.desc[head].addr = cpu_to_le64(addr); |
|
vq->packed.vring.desc[head].len = cpu_to_le32(total_sg * |
|
sizeof(struct vring_packed_desc)); |
|
vq->packed.vring.desc[head].id = cpu_to_le16(id); |
|
|
|
if (vq->use_dma_api) { |
|
vq->packed.desc_extra[id].addr = addr; |
|
vq->packed.desc_extra[id].len = total_sg * |
|
sizeof(struct vring_packed_desc); |
|
vq->packed.desc_extra[id].flags = VRING_DESC_F_INDIRECT | |
|
vq->packed.avail_used_flags; |
|
} |
|
|
|
/* |
|
* A driver MUST NOT make the first descriptor in the list |
|
* available before all subsequent descriptors comprising |
|
* the list are made available. |
|
*/ |
|
virtio_wmb(vq->weak_barriers); |
|
vq->packed.vring.desc[head].flags = cpu_to_le16(VRING_DESC_F_INDIRECT | |
|
vq->packed.avail_used_flags); |
|
|
|
/* We're using some buffers from the free list. */ |
|
vq->vq.num_free -= 1; |
|
|
|
/* Update free pointer */ |
|
n = head + 1; |
|
if (n >= vq->packed.vring.num) { |
|
n = 0; |
|
vq->packed.avail_wrap_counter ^= 1; |
|
vq->packed.avail_used_flags ^= |
|
1 << VRING_PACKED_DESC_F_AVAIL | |
|
1 << VRING_PACKED_DESC_F_USED; |
|
} |
|
vq->packed.next_avail_idx = n; |
|
vq->free_head = vq->packed.desc_state[id].next; |
|
|
|
/* Store token and indirect buffer state. */ |
|
vq->packed.desc_state[id].num = 1; |
|
vq->packed.desc_state[id].data = data; |
|
vq->packed.desc_state[id].indir_desc = desc; |
|
vq->packed.desc_state[id].last = id; |
|
|
|
vq->num_added += 1; |
|
|
|
pr_debug("Added buffer head %i to %p\n", head, vq); |
|
END_USE(vq); |
|
|
|
return 0; |
|
|
|
unmap_release: |
|
err_idx = i; |
|
|
|
for (i = 0; i < err_idx; i++) |
|
vring_unmap_desc_packed(vq, &desc[i]); |
|
|
|
kfree(desc); |
|
|
|
END_USE(vq); |
|
return -ENOMEM; |
|
} |
|
|
|
static inline int virtqueue_add_packed(struct virtqueue *_vq, |
|
struct scatterlist *sgs[], |
|
unsigned int total_sg, |
|
unsigned int out_sgs, |
|
unsigned int in_sgs, |
|
void *data, |
|
void *ctx, |
|
gfp_t gfp) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
struct vring_packed_desc *desc; |
|
struct scatterlist *sg; |
|
unsigned int i, n, c, descs_used, err_idx; |
|
__le16 head_flags, flags; |
|
u16 head, id, prev, curr, avail_used_flags; |
|
|
|
START_USE(vq); |
|
|
|
BUG_ON(data == NULL); |
|
BUG_ON(ctx && vq->indirect); |
|
|
|
if (unlikely(vq->broken)) { |
|
END_USE(vq); |
|
return -EIO; |
|
} |
|
|
|
LAST_ADD_TIME_UPDATE(vq); |
|
|
|
BUG_ON(total_sg == 0); |
|
|
|
if (virtqueue_use_indirect(_vq, total_sg)) |
|
return virtqueue_add_indirect_packed(vq, sgs, total_sg, |
|
out_sgs, in_sgs, data, gfp); |
|
|
|
head = vq->packed.next_avail_idx; |
|
avail_used_flags = vq->packed.avail_used_flags; |
|
|
|
WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect); |
|
|
|
desc = vq->packed.vring.desc; |
|
i = head; |
|
descs_used = total_sg; |
|
|
|
if (unlikely(vq->vq.num_free < descs_used)) { |
|
pr_debug("Can't add buf len %i - avail = %i\n", |
|
descs_used, vq->vq.num_free); |
|
END_USE(vq); |
|
return -ENOSPC; |
|
} |
|
|
|
id = vq->free_head; |
|
BUG_ON(id == vq->packed.vring.num); |
|
|
|
curr = id; |
|
c = 0; |
|
for (n = 0; n < out_sgs + in_sgs; n++) { |
|
for (sg = sgs[n]; sg; sg = sg_next(sg)) { |
|
dma_addr_t addr = vring_map_one_sg(vq, sg, n < out_sgs ? |
|
DMA_TO_DEVICE : DMA_FROM_DEVICE); |
|
if (vring_mapping_error(vq, addr)) |
|
goto unmap_release; |
|
|
|
flags = cpu_to_le16(vq->packed.avail_used_flags | |
|
(++c == total_sg ? 0 : VRING_DESC_F_NEXT) | |
|
(n < out_sgs ? 0 : VRING_DESC_F_WRITE)); |
|
if (i == head) |
|
head_flags = flags; |
|
else |
|
desc[i].flags = flags; |
|
|
|
desc[i].addr = cpu_to_le64(addr); |
|
desc[i].len = cpu_to_le32(sg->length); |
|
desc[i].id = cpu_to_le16(id); |
|
|
|
if (unlikely(vq->use_dma_api)) { |
|
vq->packed.desc_extra[curr].addr = addr; |
|
vq->packed.desc_extra[curr].len = sg->length; |
|
vq->packed.desc_extra[curr].flags = |
|
le16_to_cpu(flags); |
|
} |
|
prev = curr; |
|
curr = vq->packed.desc_state[curr].next; |
|
|
|
if ((unlikely(++i >= vq->packed.vring.num))) { |
|
i = 0; |
|
vq->packed.avail_used_flags ^= |
|
1 << VRING_PACKED_DESC_F_AVAIL | |
|
1 << VRING_PACKED_DESC_F_USED; |
|
} |
|
} |
|
} |
|
|
|
if (i < head) |
|
vq->packed.avail_wrap_counter ^= 1; |
|
|
|
/* We're using some buffers from the free list. */ |
|
vq->vq.num_free -= descs_used; |
|
|
|
/* Update free pointer */ |
|
vq->packed.next_avail_idx = i; |
|
vq->free_head = curr; |
|
|
|
/* Store token. */ |
|
vq->packed.desc_state[id].num = descs_used; |
|
vq->packed.desc_state[id].data = data; |
|
vq->packed.desc_state[id].indir_desc = ctx; |
|
vq->packed.desc_state[id].last = prev; |
|
|
|
/* |
|
* A driver MUST NOT make the first descriptor in the list |
|
* available before all subsequent descriptors comprising |
|
* the list are made available. |
|
*/ |
|
virtio_wmb(vq->weak_barriers); |
|
vq->packed.vring.desc[head].flags = head_flags; |
|
vq->num_added += descs_used; |
|
|
|
pr_debug("Added buffer head %i to %p\n", head, vq); |
|
END_USE(vq); |
|
|
|
return 0; |
|
|
|
unmap_release: |
|
err_idx = i; |
|
i = head; |
|
|
|
vq->packed.avail_used_flags = avail_used_flags; |
|
|
|
for (n = 0; n < total_sg; n++) { |
|
if (i == err_idx) |
|
break; |
|
vring_unmap_desc_packed(vq, &desc[i]); |
|
i++; |
|
if (i >= vq->packed.vring.num) |
|
i = 0; |
|
} |
|
|
|
END_USE(vq); |
|
return -EIO; |
|
} |
|
|
|
static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
u16 new, old, off_wrap, flags, wrap_counter, event_idx; |
|
bool needs_kick; |
|
union { |
|
struct { |
|
__le16 off_wrap; |
|
__le16 flags; |
|
}; |
|
u32 u32; |
|
} snapshot; |
|
|
|
START_USE(vq); |
|
|
|
/* |
|
* We need to expose the new flags value before checking notification |
|
* suppressions. |
|
*/ |
|
virtio_mb(vq->weak_barriers); |
|
|
|
old = vq->packed.next_avail_idx - vq->num_added; |
|
new = vq->packed.next_avail_idx; |
|
vq->num_added = 0; |
|
|
|
snapshot.u32 = *(u32 *)vq->packed.vring.device; |
|
flags = le16_to_cpu(snapshot.flags); |
|
|
|
LAST_ADD_TIME_CHECK(vq); |
|
LAST_ADD_TIME_INVALID(vq); |
|
|
|
if (flags != VRING_PACKED_EVENT_FLAG_DESC) { |
|
needs_kick = (flags != VRING_PACKED_EVENT_FLAG_DISABLE); |
|
goto out; |
|
} |
|
|
|
off_wrap = le16_to_cpu(snapshot.off_wrap); |
|
|
|
wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR; |
|
event_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR); |
|
if (wrap_counter != vq->packed.avail_wrap_counter) |
|
event_idx -= vq->packed.vring.num; |
|
|
|
needs_kick = vring_need_event(event_idx, new, old); |
|
out: |
|
END_USE(vq); |
|
return needs_kick; |
|
} |
|
|
|
static void detach_buf_packed(struct vring_virtqueue *vq, |
|
unsigned int id, void **ctx) |
|
{ |
|
struct vring_desc_state_packed *state = NULL; |
|
struct vring_packed_desc *desc; |
|
unsigned int i, curr; |
|
|
|
state = &vq->packed.desc_state[id]; |
|
|
|
/* Clear data ptr. */ |
|
state->data = NULL; |
|
|
|
vq->packed.desc_state[state->last].next = vq->free_head; |
|
vq->free_head = id; |
|
vq->vq.num_free += state->num; |
|
|
|
if (unlikely(vq->use_dma_api)) { |
|
curr = id; |
|
for (i = 0; i < state->num; i++) { |
|
vring_unmap_state_packed(vq, |
|
&vq->packed.desc_extra[curr]); |
|
curr = vq->packed.desc_state[curr].next; |
|
} |
|
} |
|
|
|
if (vq->indirect) { |
|
u32 len; |
|
|
|
/* Free the indirect table, if any, now that it's unmapped. */ |
|
desc = state->indir_desc; |
|
if (!desc) |
|
return; |
|
|
|
if (vq->use_dma_api) { |
|
len = vq->packed.desc_extra[id].len; |
|
for (i = 0; i < len / sizeof(struct vring_packed_desc); |
|
i++) |
|
vring_unmap_desc_packed(vq, &desc[i]); |
|
} |
|
kfree(desc); |
|
state->indir_desc = NULL; |
|
} else if (ctx) { |
|
*ctx = state->indir_desc; |
|
} |
|
} |
|
|
|
static inline bool is_used_desc_packed(const struct vring_virtqueue *vq, |
|
u16 idx, bool used_wrap_counter) |
|
{ |
|
bool avail, used; |
|
u16 flags; |
|
|
|
flags = le16_to_cpu(vq->packed.vring.desc[idx].flags); |
|
avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL)); |
|
used = !!(flags & (1 << VRING_PACKED_DESC_F_USED)); |
|
|
|
return avail == used && used == used_wrap_counter; |
|
} |
|
|
|
static inline bool more_used_packed(const struct vring_virtqueue *vq) |
|
{ |
|
return is_used_desc_packed(vq, vq->last_used_idx, |
|
vq->packed.used_wrap_counter); |
|
} |
|
|
|
static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, |
|
unsigned int *len, |
|
void **ctx) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
u16 last_used, id; |
|
void *ret; |
|
|
|
START_USE(vq); |
|
|
|
if (unlikely(vq->broken)) { |
|
END_USE(vq); |
|
return NULL; |
|
} |
|
|
|
if (!more_used_packed(vq)) { |
|
pr_debug("No more buffers in queue\n"); |
|
END_USE(vq); |
|
return NULL; |
|
} |
|
|
|
/* Only get used elements after they have been exposed by host. */ |
|
virtio_rmb(vq->weak_barriers); |
|
|
|
last_used = vq->last_used_idx; |
|
id = le16_to_cpu(vq->packed.vring.desc[last_used].id); |
|
*len = le32_to_cpu(vq->packed.vring.desc[last_used].len); |
|
|
|
if (unlikely(id >= vq->packed.vring.num)) { |
|
BAD_RING(vq, "id %u out of range\n", id); |
|
return NULL; |
|
} |
|
if (unlikely(!vq->packed.desc_state[id].data)) { |
|
BAD_RING(vq, "id %u is not a head!\n", id); |
|
return NULL; |
|
} |
|
|
|
/* detach_buf_packed clears data, so grab it now. */ |
|
ret = vq->packed.desc_state[id].data; |
|
detach_buf_packed(vq, id, ctx); |
|
|
|
vq->last_used_idx += vq->packed.desc_state[id].num; |
|
if (unlikely(vq->last_used_idx >= vq->packed.vring.num)) { |
|
vq->last_used_idx -= vq->packed.vring.num; |
|
vq->packed.used_wrap_counter ^= 1; |
|
} |
|
|
|
/* |
|
* If we expect an interrupt for the next entry, tell host |
|
* by writing event index and flush out the write before |
|
* the read in the next get_buf call. |
|
*/ |
|
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DESC) |
|
virtio_store_mb(vq->weak_barriers, |
|
&vq->packed.vring.driver->off_wrap, |
|
cpu_to_le16(vq->last_used_idx | |
|
(vq->packed.used_wrap_counter << |
|
VRING_PACKED_EVENT_F_WRAP_CTR))); |
|
|
|
LAST_ADD_TIME_INVALID(vq); |
|
|
|
END_USE(vq); |
|
return ret; |
|
} |
|
|
|
static void virtqueue_disable_cb_packed(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (vq->packed.event_flags_shadow != VRING_PACKED_EVENT_FLAG_DISABLE) { |
|
vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE; |
|
vq->packed.vring.driver->flags = |
|
cpu_to_le16(vq->packed.event_flags_shadow); |
|
} |
|
} |
|
|
|
static unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
START_USE(vq); |
|
|
|
/* |
|
* We optimistically turn back on interrupts, then check if there was |
|
* more to do. |
|
*/ |
|
|
|
if (vq->event) { |
|
vq->packed.vring.driver->off_wrap = |
|
cpu_to_le16(vq->last_used_idx | |
|
(vq->packed.used_wrap_counter << |
|
VRING_PACKED_EVENT_F_WRAP_CTR)); |
|
/* |
|
* We need to update event offset and event wrap |
|
* counter first before updating event flags. |
|
*/ |
|
virtio_wmb(vq->weak_barriers); |
|
} |
|
|
|
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) { |
|
vq->packed.event_flags_shadow = vq->event ? |
|
VRING_PACKED_EVENT_FLAG_DESC : |
|
VRING_PACKED_EVENT_FLAG_ENABLE; |
|
vq->packed.vring.driver->flags = |
|
cpu_to_le16(vq->packed.event_flags_shadow); |
|
} |
|
|
|
END_USE(vq); |
|
return vq->last_used_idx | ((u16)vq->packed.used_wrap_counter << |
|
VRING_PACKED_EVENT_F_WRAP_CTR); |
|
} |
|
|
|
static bool virtqueue_poll_packed(struct virtqueue *_vq, u16 off_wrap) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
bool wrap_counter; |
|
u16 used_idx; |
|
|
|
wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR; |
|
used_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR); |
|
|
|
return is_used_desc_packed(vq, used_idx, wrap_counter); |
|
} |
|
|
|
static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
u16 used_idx, wrap_counter; |
|
u16 bufs; |
|
|
|
START_USE(vq); |
|
|
|
/* |
|
* We optimistically turn back on interrupts, then check if there was |
|
* more to do. |
|
*/ |
|
|
|
if (vq->event) { |
|
/* TODO: tune this threshold */ |
|
bufs = (vq->packed.vring.num - vq->vq.num_free) * 3 / 4; |
|
wrap_counter = vq->packed.used_wrap_counter; |
|
|
|
used_idx = vq->last_used_idx + bufs; |
|
if (used_idx >= vq->packed.vring.num) { |
|
used_idx -= vq->packed.vring.num; |
|
wrap_counter ^= 1; |
|
} |
|
|
|
vq->packed.vring.driver->off_wrap = cpu_to_le16(used_idx | |
|
(wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR)); |
|
|
|
/* |
|
* We need to update event offset and event wrap |
|
* counter first before updating event flags. |
|
*/ |
|
virtio_wmb(vq->weak_barriers); |
|
} |
|
|
|
if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) { |
|
vq->packed.event_flags_shadow = vq->event ? |
|
VRING_PACKED_EVENT_FLAG_DESC : |
|
VRING_PACKED_EVENT_FLAG_ENABLE; |
|
vq->packed.vring.driver->flags = |
|
cpu_to_le16(vq->packed.event_flags_shadow); |
|
} |
|
|
|
/* |
|
* We need to update event suppression structure first |
|
* before re-checking for more used buffers. |
|
*/ |
|
virtio_mb(vq->weak_barriers); |
|
|
|
if (is_used_desc_packed(vq, |
|
vq->last_used_idx, |
|
vq->packed.used_wrap_counter)) { |
|
END_USE(vq); |
|
return false; |
|
} |
|
|
|
END_USE(vq); |
|
return true; |
|
} |
|
|
|
static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
unsigned int i; |
|
void *buf; |
|
|
|
START_USE(vq); |
|
|
|
for (i = 0; i < vq->packed.vring.num; i++) { |
|
if (!vq->packed.desc_state[i].data) |
|
continue; |
|
/* detach_buf clears data, so grab it now. */ |
|
buf = vq->packed.desc_state[i].data; |
|
detach_buf_packed(vq, i, NULL); |
|
END_USE(vq); |
|
return buf; |
|
} |
|
/* That should have freed everything. */ |
|
BUG_ON(vq->vq.num_free != vq->packed.vring.num); |
|
|
|
END_USE(vq); |
|
return NULL; |
|
} |
|
|
|
static struct virtqueue *vring_create_virtqueue_packed( |
|
unsigned int index, |
|
unsigned int num, |
|
unsigned int vring_align, |
|
struct virtio_device *vdev, |
|
bool weak_barriers, |
|
bool may_reduce_num, |
|
bool context, |
|
bool (*notify)(struct virtqueue *), |
|
void (*callback)(struct virtqueue *), |
|
const char *name) |
|
{ |
|
struct vring_virtqueue *vq; |
|
struct vring_packed_desc *ring; |
|
struct vring_packed_desc_event *driver, *device; |
|
dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr; |
|
size_t ring_size_in_bytes, event_size_in_bytes; |
|
unsigned int i; |
|
|
|
ring_size_in_bytes = num * sizeof(struct vring_packed_desc); |
|
|
|
ring = vring_alloc_queue(vdev, ring_size_in_bytes, |
|
&ring_dma_addr, |
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); |
|
if (!ring) |
|
goto err_ring; |
|
|
|
event_size_in_bytes = sizeof(struct vring_packed_desc_event); |
|
|
|
driver = vring_alloc_queue(vdev, event_size_in_bytes, |
|
&driver_event_dma_addr, |
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); |
|
if (!driver) |
|
goto err_driver; |
|
|
|
device = vring_alloc_queue(vdev, event_size_in_bytes, |
|
&device_event_dma_addr, |
|
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); |
|
if (!device) |
|
goto err_device; |
|
|
|
vq = kmalloc(sizeof(*vq), GFP_KERNEL); |
|
if (!vq) |
|
goto err_vq; |
|
|
|
vq->vq.callback = callback; |
|
vq->vq.vdev = vdev; |
|
vq->vq.name = name; |
|
vq->vq.num_free = num; |
|
vq->vq.index = index; |
|
vq->we_own_ring = true; |
|
vq->notify = notify; |
|
vq->weak_barriers = weak_barriers; |
|
vq->broken = false; |
|
vq->last_used_idx = 0; |
|
vq->num_added = 0; |
|
vq->packed_ring = true; |
|
vq->use_dma_api = vring_use_dma_api(vdev); |
|
#ifdef DEBUG |
|
vq->in_use = false; |
|
vq->last_add_time_valid = false; |
|
#endif |
|
|
|
vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && |
|
!context; |
|
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); |
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) |
|
vq->weak_barriers = false; |
|
|
|
vq->packed.ring_dma_addr = ring_dma_addr; |
|
vq->packed.driver_event_dma_addr = driver_event_dma_addr; |
|
vq->packed.device_event_dma_addr = device_event_dma_addr; |
|
|
|
vq->packed.ring_size_in_bytes = ring_size_in_bytes; |
|
vq->packed.event_size_in_bytes = event_size_in_bytes; |
|
|
|
vq->packed.vring.num = num; |
|
vq->packed.vring.desc = ring; |
|
vq->packed.vring.driver = driver; |
|
vq->packed.vring.device = device; |
|
|
|
vq->packed.next_avail_idx = 0; |
|
vq->packed.avail_wrap_counter = 1; |
|
vq->packed.used_wrap_counter = 1; |
|
vq->packed.event_flags_shadow = 0; |
|
vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL; |
|
|
|
vq->packed.desc_state = kmalloc_array(num, |
|
sizeof(struct vring_desc_state_packed), |
|
GFP_KERNEL); |
|
if (!vq->packed.desc_state) |
|
goto err_desc_state; |
|
|
|
memset(vq->packed.desc_state, 0, |
|
num * sizeof(struct vring_desc_state_packed)); |
|
|
|
/* Put everything in free lists. */ |
|
vq->free_head = 0; |
|
for (i = 0; i < num-1; i++) |
|
vq->packed.desc_state[i].next = i + 1; |
|
|
|
vq->packed.desc_extra = kmalloc_array(num, |
|
sizeof(struct vring_desc_extra_packed), |
|
GFP_KERNEL); |
|
if (!vq->packed.desc_extra) |
|
goto err_desc_extra; |
|
|
|
memset(vq->packed.desc_extra, 0, |
|
num * sizeof(struct vring_desc_extra_packed)); |
|
|
|
/* No callback? Tell other side not to bother us. */ |
|
if (!callback) { |
|
vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE; |
|
vq->packed.vring.driver->flags = |
|
cpu_to_le16(vq->packed.event_flags_shadow); |
|
} |
|
|
|
list_add_tail(&vq->vq.list, &vdev->vqs); |
|
return &vq->vq; |
|
|
|
err_desc_extra: |
|
kfree(vq->packed.desc_state); |
|
err_desc_state: |
|
kfree(vq); |
|
err_vq: |
|
vring_free_queue(vdev, event_size_in_bytes, device, device_event_dma_addr); |
|
err_device: |
|
vring_free_queue(vdev, event_size_in_bytes, driver, driver_event_dma_addr); |
|
err_driver: |
|
vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr); |
|
err_ring: |
|
return NULL; |
|
} |
|
|
|
|
|
/* |
|
* Generic functions and exported symbols. |
|
*/ |
|
|
|
static inline int virtqueue_add(struct virtqueue *_vq, |
|
struct scatterlist *sgs[], |
|
unsigned int total_sg, |
|
unsigned int out_sgs, |
|
unsigned int in_sgs, |
|
void *data, |
|
void *ctx, |
|
gfp_t gfp) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? virtqueue_add_packed(_vq, sgs, total_sg, |
|
out_sgs, in_sgs, data, ctx, gfp) : |
|
virtqueue_add_split(_vq, sgs, total_sg, |
|
out_sgs, in_sgs, data, ctx, gfp); |
|
} |
|
|
|
/** |
|
* virtqueue_add_sgs - expose buffers to other end |
|
* @_vq: the struct virtqueue we're talking about. |
|
* @sgs: array of terminated scatterlists. |
|
* @out_sgs: the number of scatterlists readable by other side |
|
* @in_sgs: the number of scatterlists which are writable (after readable ones) |
|
* @data: the token identifying the buffer. |
|
* @gfp: how to do memory allocations (if necessary). |
|
* |
|
* Caller must ensure we don't call this with other virtqueue operations |
|
* at the same time (except where noted). |
|
* |
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
|
*/ |
|
int virtqueue_add_sgs(struct virtqueue *_vq, |
|
struct scatterlist *sgs[], |
|
unsigned int out_sgs, |
|
unsigned int in_sgs, |
|
void *data, |
|
gfp_t gfp) |
|
{ |
|
unsigned int i, total_sg = 0; |
|
|
|
/* Count them first. */ |
|
for (i = 0; i < out_sgs + in_sgs; i++) { |
|
struct scatterlist *sg; |
|
|
|
for (sg = sgs[i]; sg; sg = sg_next(sg)) |
|
total_sg++; |
|
} |
|
return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs, |
|
data, NULL, gfp); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_add_sgs); |
|
|
|
/** |
|
* virtqueue_add_outbuf - expose output buffers to other end |
|
* @vq: the struct virtqueue we're talking about. |
|
* @sg: scatterlist (must be well-formed and terminated!) |
|
* @num: the number of entries in @sg readable by other side |
|
* @data: the token identifying the buffer. |
|
* @gfp: how to do memory allocations (if necessary). |
|
* |
|
* Caller must ensure we don't call this with other virtqueue operations |
|
* at the same time (except where noted). |
|
* |
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
|
*/ |
|
int virtqueue_add_outbuf(struct virtqueue *vq, |
|
struct scatterlist *sg, unsigned int num, |
|
void *data, |
|
gfp_t gfp) |
|
{ |
|
return virtqueue_add(vq, &sg, num, 1, 0, data, NULL, gfp); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); |
|
|
|
/** |
|
* virtqueue_add_inbuf - expose input buffers to other end |
|
* @vq: the struct virtqueue we're talking about. |
|
* @sg: scatterlist (must be well-formed and terminated!) |
|
* @num: the number of entries in @sg writable by other side |
|
* @data: the token identifying the buffer. |
|
* @gfp: how to do memory allocations (if necessary). |
|
* |
|
* Caller must ensure we don't call this with other virtqueue operations |
|
* at the same time (except where noted). |
|
* |
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
|
*/ |
|
int virtqueue_add_inbuf(struct virtqueue *vq, |
|
struct scatterlist *sg, unsigned int num, |
|
void *data, |
|
gfp_t gfp) |
|
{ |
|
return virtqueue_add(vq, &sg, num, 0, 1, data, NULL, gfp); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf); |
|
|
|
/** |
|
* virtqueue_add_inbuf_ctx - expose input buffers to other end |
|
* @vq: the struct virtqueue we're talking about. |
|
* @sg: scatterlist (must be well-formed and terminated!) |
|
* @num: the number of entries in @sg writable by other side |
|
* @data: the token identifying the buffer. |
|
* @ctx: extra context for the token |
|
* @gfp: how to do memory allocations (if necessary). |
|
* |
|
* Caller must ensure we don't call this with other virtqueue operations |
|
* at the same time (except where noted). |
|
* |
|
* Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). |
|
*/ |
|
int virtqueue_add_inbuf_ctx(struct virtqueue *vq, |
|
struct scatterlist *sg, unsigned int num, |
|
void *data, |
|
void *ctx, |
|
gfp_t gfp) |
|
{ |
|
return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx); |
|
|
|
/** |
|
* virtqueue_kick_prepare - first half of split virtqueue_kick call. |
|
* @_vq: the struct virtqueue |
|
* |
|
* Instead of virtqueue_kick(), you can do: |
|
* if (virtqueue_kick_prepare(vq)) |
|
* virtqueue_notify(vq); |
|
* |
|
* This is sometimes useful because the virtqueue_kick_prepare() needs |
|
* to be serialized, but the actual virtqueue_notify() call does not. |
|
*/ |
|
bool virtqueue_kick_prepare(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? virtqueue_kick_prepare_packed(_vq) : |
|
virtqueue_kick_prepare_split(_vq); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_kick_prepare); |
|
|
|
/** |
|
* virtqueue_notify - second half of split virtqueue_kick call. |
|
* @_vq: the struct virtqueue |
|
* |
|
* This does not need to be serialized. |
|
* |
|
* Returns false if host notify failed or queue is broken, otherwise true. |
|
*/ |
|
bool virtqueue_notify(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (unlikely(vq->broken)) |
|
return false; |
|
|
|
/* Prod other side to tell it about changes. */ |
|
if (!vq->notify(_vq)) { |
|
vq->broken = true; |
|
return false; |
|
} |
|
return true; |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_notify); |
|
|
|
/** |
|
* virtqueue_kick - update after add_buf |
|
* @vq: the struct virtqueue |
|
* |
|
* After one or more virtqueue_add_* calls, invoke this to kick |
|
* the other side. |
|
* |
|
* Caller must ensure we don't call this with other virtqueue |
|
* operations at the same time (except where noted). |
|
* |
|
* Returns false if kick failed, otherwise true. |
|
*/ |
|
bool virtqueue_kick(struct virtqueue *vq) |
|
{ |
|
if (virtqueue_kick_prepare(vq)) |
|
return virtqueue_notify(vq); |
|
return true; |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_kick); |
|
|
|
/** |
|
* virtqueue_get_buf - get the next used buffer |
|
* @_vq: the struct virtqueue we're talking about. |
|
* @len: the length written into the buffer |
|
* @ctx: extra context for the token |
|
* |
|
* If the device wrote data into the buffer, @len will be set to the |
|
* amount written. This means you don't need to clear the buffer |
|
* beforehand to ensure there's no data leakage in the case of short |
|
* writes. |
|
* |
|
* Caller must ensure we don't call this with other virtqueue |
|
* operations at the same time (except where noted). |
|
* |
|
* Returns NULL if there are no used buffers, or the "data" token |
|
* handed to virtqueue_add_*(). |
|
*/ |
|
void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, |
|
void **ctx) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) : |
|
virtqueue_get_buf_ctx_split(_vq, len, ctx); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx); |
|
|
|
void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) |
|
{ |
|
return virtqueue_get_buf_ctx(_vq, len, NULL); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_buf); |
|
/** |
|
* virtqueue_disable_cb - disable callbacks |
|
* @_vq: the struct virtqueue we're talking about. |
|
* |
|
* Note that this is not necessarily synchronous, hence unreliable and only |
|
* useful as an optimization. |
|
* |
|
* Unlike other operations, this need not be serialized. |
|
*/ |
|
void virtqueue_disable_cb(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (vq->packed_ring) |
|
virtqueue_disable_cb_packed(_vq); |
|
else |
|
virtqueue_disable_cb_split(_vq); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_disable_cb); |
|
|
|
/** |
|
* virtqueue_enable_cb_prepare - restart callbacks after disable_cb |
|
* @_vq: the struct virtqueue we're talking about. |
|
* |
|
* This re-enables callbacks; it returns current queue state |
|
* in an opaque unsigned value. This value should be later tested by |
|
* virtqueue_poll, to detect a possible race between the driver checking for |
|
* more work, and enabling callbacks. |
|
* |
|
* Caller must ensure we don't call this with other virtqueue |
|
* operations at the same time (except where noted). |
|
*/ |
|
unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? virtqueue_enable_cb_prepare_packed(_vq) : |
|
virtqueue_enable_cb_prepare_split(_vq); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare); |
|
|
|
/** |
|
* virtqueue_poll - query pending used buffers |
|
* @_vq: the struct virtqueue we're talking about. |
|
* @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare). |
|
* |
|
* Returns "true" if there are pending used buffers in the queue. |
|
* |
|
* This does not need to be serialized. |
|
*/ |
|
bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (unlikely(vq->broken)) |
|
return false; |
|
|
|
virtio_mb(vq->weak_barriers); |
|
return vq->packed_ring ? virtqueue_poll_packed(_vq, last_used_idx) : |
|
virtqueue_poll_split(_vq, last_used_idx); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_poll); |
|
|
|
/** |
|
* virtqueue_enable_cb - restart callbacks after disable_cb. |
|
* @_vq: the struct virtqueue we're talking about. |
|
* |
|
* This re-enables callbacks; it returns "false" if there are pending |
|
* buffers in the queue, to detect a possible race between the driver |
|
* checking for more work, and enabling callbacks. |
|
* |
|
* Caller must ensure we don't call this with other virtqueue |
|
* operations at the same time (except where noted). |
|
*/ |
|
bool virtqueue_enable_cb(struct virtqueue *_vq) |
|
{ |
|
unsigned last_used_idx = virtqueue_enable_cb_prepare(_vq); |
|
|
|
return !virtqueue_poll(_vq, last_used_idx); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb); |
|
|
|
/** |
|
* virtqueue_enable_cb_delayed - restart callbacks after disable_cb. |
|
* @_vq: the struct virtqueue we're talking about. |
|
* |
|
* This re-enables callbacks but hints to the other side to delay |
|
* interrupts until most of the available buffers have been processed; |
|
* it returns "false" if there are many pending buffers in the queue, |
|
* to detect a possible race between the driver checking for more work, |
|
* and enabling callbacks. |
|
* |
|
* Caller must ensure we don't call this with other virtqueue |
|
* operations at the same time (except where noted). |
|
*/ |
|
bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? virtqueue_enable_cb_delayed_packed(_vq) : |
|
virtqueue_enable_cb_delayed_split(_vq); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed); |
|
|
|
/** |
|
* virtqueue_detach_unused_buf - detach first unused buffer |
|
* @_vq: the struct virtqueue we're talking about. |
|
* |
|
* Returns NULL or the "data" token handed to virtqueue_add_*(). |
|
* This is not valid on an active queue; it is useful only for device |
|
* shutdown. |
|
*/ |
|
void *virtqueue_detach_unused_buf(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? virtqueue_detach_unused_buf_packed(_vq) : |
|
virtqueue_detach_unused_buf_split(_vq); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf); |
|
|
|
static inline bool more_used(const struct vring_virtqueue *vq) |
|
{ |
|
return vq->packed_ring ? more_used_packed(vq) : more_used_split(vq); |
|
} |
|
|
|
irqreturn_t vring_interrupt(int irq, void *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (!more_used(vq)) { |
|
pr_debug("virtqueue interrupt with no work for %p\n", vq); |
|
return IRQ_NONE; |
|
} |
|
|
|
if (unlikely(vq->broken)) |
|
return IRQ_HANDLED; |
|
|
|
pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback); |
|
if (vq->vq.callback) |
|
vq->vq.callback(&vq->vq); |
|
|
|
return IRQ_HANDLED; |
|
} |
|
EXPORT_SYMBOL_GPL(vring_interrupt); |
|
|
|
/* Only available for split ring */ |
|
struct virtqueue *__vring_new_virtqueue(unsigned int index, |
|
struct vring vring, |
|
struct virtio_device *vdev, |
|
bool weak_barriers, |
|
bool context, |
|
bool (*notify)(struct virtqueue *), |
|
void (*callback)(struct virtqueue *), |
|
const char *name) |
|
{ |
|
unsigned int i; |
|
struct vring_virtqueue *vq; |
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) |
|
return NULL; |
|
|
|
vq = kmalloc(sizeof(*vq), GFP_KERNEL); |
|
if (!vq) |
|
return NULL; |
|
|
|
vq->packed_ring = false; |
|
vq->vq.callback = callback; |
|
vq->vq.vdev = vdev; |
|
vq->vq.name = name; |
|
vq->vq.num_free = vring.num; |
|
vq->vq.index = index; |
|
vq->we_own_ring = false; |
|
vq->notify = notify; |
|
vq->weak_barriers = weak_barriers; |
|
vq->broken = false; |
|
vq->last_used_idx = 0; |
|
vq->num_added = 0; |
|
vq->use_dma_api = vring_use_dma_api(vdev); |
|
#ifdef DEBUG |
|
vq->in_use = false; |
|
vq->last_add_time_valid = false; |
|
#endif |
|
|
|
vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) && |
|
!context; |
|
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); |
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM)) |
|
vq->weak_barriers = false; |
|
|
|
vq->split.queue_dma_addr = 0; |
|
vq->split.queue_size_in_bytes = 0; |
|
|
|
vq->split.vring = vring; |
|
vq->split.avail_flags_shadow = 0; |
|
vq->split.avail_idx_shadow = 0; |
|
|
|
/* No callback? Tell other side not to bother us. */ |
|
if (!callback) { |
|
vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; |
|
if (!vq->event) |
|
vq->split.vring.avail->flags = cpu_to_virtio16(vdev, |
|
vq->split.avail_flags_shadow); |
|
} |
|
|
|
vq->split.desc_state = kmalloc_array(vring.num, |
|
sizeof(struct vring_desc_state_split), GFP_KERNEL); |
|
if (!vq->split.desc_state) { |
|
kfree(vq); |
|
return NULL; |
|
} |
|
|
|
/* Put everything in free lists. */ |
|
vq->free_head = 0; |
|
for (i = 0; i < vring.num-1; i++) |
|
vq->split.vring.desc[i].next = cpu_to_virtio16(vdev, i + 1); |
|
memset(vq->split.desc_state, 0, vring.num * |
|
sizeof(struct vring_desc_state_split)); |
|
|
|
list_add_tail(&vq->vq.list, &vdev->vqs); |
|
return &vq->vq; |
|
} |
|
EXPORT_SYMBOL_GPL(__vring_new_virtqueue); |
|
|
|
struct virtqueue *vring_create_virtqueue( |
|
unsigned int index, |
|
unsigned int num, |
|
unsigned int vring_align, |
|
struct virtio_device *vdev, |
|
bool weak_barriers, |
|
bool may_reduce_num, |
|
bool context, |
|
bool (*notify)(struct virtqueue *), |
|
void (*callback)(struct virtqueue *), |
|
const char *name) |
|
{ |
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) |
|
return vring_create_virtqueue_packed(index, num, vring_align, |
|
vdev, weak_barriers, may_reduce_num, |
|
context, notify, callback, name); |
|
|
|
return vring_create_virtqueue_split(index, num, vring_align, |
|
vdev, weak_barriers, may_reduce_num, |
|
context, notify, callback, name); |
|
} |
|
EXPORT_SYMBOL_GPL(vring_create_virtqueue); |
|
|
|
/* Only available for split ring */ |
|
struct virtqueue *vring_new_virtqueue(unsigned int index, |
|
unsigned int num, |
|
unsigned int vring_align, |
|
struct virtio_device *vdev, |
|
bool weak_barriers, |
|
bool context, |
|
void *pages, |
|
bool (*notify)(struct virtqueue *vq), |
|
void (*callback)(struct virtqueue *vq), |
|
const char *name) |
|
{ |
|
struct vring vring; |
|
|
|
if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED)) |
|
return NULL; |
|
|
|
vring_init(&vring, num, pages, vring_align); |
|
return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context, |
|
notify, callback, name); |
|
} |
|
EXPORT_SYMBOL_GPL(vring_new_virtqueue); |
|
|
|
void vring_del_virtqueue(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
if (vq->we_own_ring) { |
|
if (vq->packed_ring) { |
|
vring_free_queue(vq->vq.vdev, |
|
vq->packed.ring_size_in_bytes, |
|
vq->packed.vring.desc, |
|
vq->packed.ring_dma_addr); |
|
|
|
vring_free_queue(vq->vq.vdev, |
|
vq->packed.event_size_in_bytes, |
|
vq->packed.vring.driver, |
|
vq->packed.driver_event_dma_addr); |
|
|
|
vring_free_queue(vq->vq.vdev, |
|
vq->packed.event_size_in_bytes, |
|
vq->packed.vring.device, |
|
vq->packed.device_event_dma_addr); |
|
|
|
kfree(vq->packed.desc_state); |
|
kfree(vq->packed.desc_extra); |
|
} else { |
|
vring_free_queue(vq->vq.vdev, |
|
vq->split.queue_size_in_bytes, |
|
vq->split.vring.desc, |
|
vq->split.queue_dma_addr); |
|
} |
|
} |
|
if (!vq->packed_ring) |
|
kfree(vq->split.desc_state); |
|
list_del(&_vq->list); |
|
kfree(vq); |
|
} |
|
EXPORT_SYMBOL_GPL(vring_del_virtqueue); |
|
|
|
/* Manipulates transport-specific feature bits. */ |
|
void vring_transport_features(struct virtio_device *vdev) |
|
{ |
|
unsigned int i; |
|
|
|
for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { |
|
switch (i) { |
|
case VIRTIO_RING_F_INDIRECT_DESC: |
|
break; |
|
case VIRTIO_RING_F_EVENT_IDX: |
|
break; |
|
case VIRTIO_F_VERSION_1: |
|
break; |
|
case VIRTIO_F_ACCESS_PLATFORM: |
|
break; |
|
case VIRTIO_F_RING_PACKED: |
|
break; |
|
case VIRTIO_F_ORDER_PLATFORM: |
|
break; |
|
default: |
|
/* We don't understand this bit. */ |
|
__virtio_clear_bit(vdev, i); |
|
} |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(vring_transport_features); |
|
|
|
/** |
|
* virtqueue_get_vring_size - return the size of the virtqueue's vring |
|
* @_vq: the struct virtqueue containing the vring of interest. |
|
* |
|
* Returns the size of the vring. This is mainly used for boasting to |
|
* userspace. Unlike other operations, this need not be serialized. |
|
*/ |
|
unsigned int virtqueue_get_vring_size(struct virtqueue *_vq) |
|
{ |
|
|
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num; |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_vring_size); |
|
|
|
bool virtqueue_is_broken(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
return vq->broken; |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_is_broken); |
|
|
|
/* |
|
* This should prevent the device from being used, allowing drivers to |
|
* recover. You may need to grab appropriate locks to flush. |
|
*/ |
|
void virtio_break_device(struct virtio_device *dev) |
|
{ |
|
struct virtqueue *_vq; |
|
|
|
list_for_each_entry(_vq, &dev->vqs, list) { |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
vq->broken = true; |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(virtio_break_device); |
|
|
|
dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
BUG_ON(!vq->we_own_ring); |
|
|
|
if (vq->packed_ring) |
|
return vq->packed.ring_dma_addr; |
|
|
|
return vq->split.queue_dma_addr; |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr); |
|
|
|
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
BUG_ON(!vq->we_own_ring); |
|
|
|
if (vq->packed_ring) |
|
return vq->packed.driver_event_dma_addr; |
|
|
|
return vq->split.queue_dma_addr + |
|
((char *)vq->split.vring.avail - (char *)vq->split.vring.desc); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr); |
|
|
|
dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) |
|
{ |
|
struct vring_virtqueue *vq = to_vvq(_vq); |
|
|
|
BUG_ON(!vq->we_own_ring); |
|
|
|
if (vq->packed_ring) |
|
return vq->packed.device_event_dma_addr; |
|
|
|
return vq->split.queue_dma_addr + |
|
((char *)vq->split.vring.used - (char *)vq->split.vring.desc); |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_used_addr); |
|
|
|
/* Only available for split ring */ |
|
const struct vring *virtqueue_get_vring(struct virtqueue *vq) |
|
{ |
|
return &to_vvq(vq)->split.vring; |
|
} |
|
EXPORT_SYMBOL_GPL(virtqueue_get_vring); |
|
|
|
MODULE_LICENSE("GPL");
|
|
|