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85 lines
2.2 KiB
85 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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// Copyright (C) 2020 Arm Ltd. |
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#include <linux/arm-smccc.h> |
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#include <linux/kvm_host.h> |
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#include <asm/kvm_emulate.h> |
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#include <kvm/arm_hypercalls.h> |
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#define ARM_SMCCC_TRNG_VERSION_1_0 0x10000UL |
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/* Those values are deliberately separate from the generic SMCCC definitions. */ |
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#define TRNG_SUCCESS 0UL |
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#define TRNG_NOT_SUPPORTED ((unsigned long)-1) |
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#define TRNG_INVALID_PARAMETER ((unsigned long)-2) |
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#define TRNG_NO_ENTROPY ((unsigned long)-3) |
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#define TRNG_MAX_BITS64 192 |
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static const uuid_t arm_smc_trng_uuid __aligned(4) = UUID_INIT( |
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0x0d21e000, 0x4384, 0x11eb, 0x80, 0x70, 0x52, 0x44, 0x55, 0x4e, 0x5a, 0x4c); |
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static int kvm_trng_do_rnd(struct kvm_vcpu *vcpu, int size) |
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{ |
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DECLARE_BITMAP(bits, TRNG_MAX_BITS64); |
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u32 num_bits = smccc_get_arg1(vcpu); |
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int i; |
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if (num_bits > 3 * size) { |
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smccc_set_retval(vcpu, TRNG_INVALID_PARAMETER, 0, 0, 0); |
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return 1; |
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} |
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/* get as many bits as we need to fulfil the request */ |
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for (i = 0; i < DIV_ROUND_UP(num_bits, BITS_PER_LONG); i++) |
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bits[i] = get_random_long(); |
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bitmap_clear(bits, num_bits, TRNG_MAX_BITS64 - num_bits); |
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if (size == 32) |
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smccc_set_retval(vcpu, TRNG_SUCCESS, lower_32_bits(bits[1]), |
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upper_32_bits(bits[0]), lower_32_bits(bits[0])); |
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else |
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smccc_set_retval(vcpu, TRNG_SUCCESS, bits[2], bits[1], bits[0]); |
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memzero_explicit(bits, sizeof(bits)); |
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return 1; |
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} |
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int kvm_trng_call(struct kvm_vcpu *vcpu) |
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{ |
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const __le32 *u = (__le32 *)arm_smc_trng_uuid.b; |
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u32 func_id = smccc_get_function(vcpu); |
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unsigned long val = TRNG_NOT_SUPPORTED; |
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int size = 64; |
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switch (func_id) { |
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case ARM_SMCCC_TRNG_VERSION: |
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val = ARM_SMCCC_TRNG_VERSION_1_0; |
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break; |
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case ARM_SMCCC_TRNG_FEATURES: |
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switch (smccc_get_arg1(vcpu)) { |
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case ARM_SMCCC_TRNG_VERSION: |
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case ARM_SMCCC_TRNG_FEATURES: |
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case ARM_SMCCC_TRNG_GET_UUID: |
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case ARM_SMCCC_TRNG_RND32: |
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case ARM_SMCCC_TRNG_RND64: |
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val = TRNG_SUCCESS; |
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} |
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break; |
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case ARM_SMCCC_TRNG_GET_UUID: |
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smccc_set_retval(vcpu, le32_to_cpu(u[0]), le32_to_cpu(u[1]), |
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le32_to_cpu(u[2]), le32_to_cpu(u[3])); |
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return 1; |
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case ARM_SMCCC_TRNG_RND32: |
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size = 32; |
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fallthrough; |
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case ARM_SMCCC_TRNG_RND64: |
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return kvm_trng_do_rnd(vcpu, size); |
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} |
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smccc_set_retval(vcpu, val, 0, 0, 0); |
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return 1; |
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}
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