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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/tools/testing/selftests/kvm/x86/flds_emulation.h
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/* SPDX-License-Identifier: GPL-2.0-only */

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#ifndef SELFTEST_KVM_FLDS_EMULATION_H

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#define SELFTEST_KVM_FLDS_EMULATION_H

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#include "kvm_util.h"

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#define FLDS_MEM_EAX ".byte 0xd9, 0x00"

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/*

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 * flds is an instruction that the KVM instruction emulator is known not to

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 * support. This can be used in guest code along with a mechanism to force

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 * KVM to emulate the instruction (e.g. by providing an MMIO address) to

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 * exercise emulation failures.

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 */

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static inline void flds(uint64_t address)

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{

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	__asm__ __volatile__(FLDS_MEM_EAX :: "a"(address));

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}

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static inline void handle_flds_emulation_failure_exit(struct kvm_vcpu *vcpu)

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{

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	struct kvm_run *run = vcpu->run;

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	struct kvm_regs regs;

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	uint8_t *insn_bytes;

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	uint64_t flags;

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	TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTERNAL_ERROR);

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	TEST_ASSERT(run->emulation_failure.suberror == KVM_INTERNAL_ERROR_EMULATION,

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		    "Unexpected suberror: %u",

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		    run->emulation_failure.suberror);

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	flags = run->emulation_failure.flags;

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	TEST_ASSERT(run->emulation_failure.ndata >= 3 &&

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		    flags & KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES,

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		    "run->emulation_failure is missing instruction bytes");

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	TEST_ASSERT(run->emulation_failure.insn_size >= 2,

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		    "Expected a 2-byte opcode for 'flds', got %d bytes",

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		    run->emulation_failure.insn_size);

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	insn_bytes = run->emulation_failure.insn_bytes;

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	TEST_ASSERT(insn_bytes[0] == 0xd9 && insn_bytes[1] == 0,

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		    "Expected 'flds [eax]', opcode '0xd9 0x00', got opcode 0x%02x 0x%02x",

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		    insn_bytes[0], insn_bytes[1]);

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	vcpu_regs_get(vcpu, &regs);

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	regs.rip += 2;

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	vcpu_regs_set(vcpu, &regs);

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}

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#endif /* !SELFTEST_KVM_FLDS_EMULATION_H */

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