1 /* SPDX-License-Identifier: GPL-2.0-only */
2 #ifndef SELFTEST_KVM_FLDS_EMULATION_H
3 #define SELFTEST_KVM_FLDS_EMULATION_H
4 
5 #include "kvm_util.h"
6 
7 #define FLDS_MEM_EAX ".byte 0xd9, 0x00"
8 
9 /*
10  * flds is an instruction that the KVM instruction emulator is known not to
11  * support. This can be used in guest code along with a mechanism to force
12  * KVM to emulate the instruction (e.g. by providing an MMIO address) to
13  * exercise emulation failures.
14  */
15 static inline void flds(uint64_t address)
16 {
17 	__asm__ __volatile__(FLDS_MEM_EAX :: "a"(address));
18 }
19 
20 static inline void handle_flds_emulation_failure_exit(struct kvm_vcpu *vcpu)
21 {
22 	struct kvm_run *run = vcpu->run;
23 	struct kvm_regs regs;
24 	uint8_t *insn_bytes;
25 	uint64_t flags;
26 
27 	TEST_ASSERT(run->exit_reason == KVM_EXIT_INTERNAL_ERROR,
28 		    "Unexpected exit reason: %u (%s)",
29 		    run->exit_reason,
30 		    exit_reason_str(run->exit_reason));
31 
32 	TEST_ASSERT(run->emulation_failure.suberror == KVM_INTERNAL_ERROR_EMULATION,
33 		    "Unexpected suberror: %u",
34 		    run->emulation_failure.suberror);
35 
36 	flags = run->emulation_failure.flags;
37 	TEST_ASSERT(run->emulation_failure.ndata >= 3 &&
38 		    flags & KVM_INTERNAL_ERROR_EMULATION_FLAG_INSTRUCTION_BYTES,
39 		    "run->emulation_failure is missing instruction bytes");
40 
41 	TEST_ASSERT(run->emulation_failure.insn_size >= 2,
42 		    "Expected a 2-byte opcode for 'flds', got %d bytes",
43 		    run->emulation_failure.insn_size);
44 
45 	insn_bytes = run->emulation_failure.insn_bytes;
46 	TEST_ASSERT(insn_bytes[0] == 0xd9 && insn_bytes[1] == 0,
47 		    "Expected 'flds [eax]', opcode '0xd9 0x00', got opcode 0x%02x 0x%02x\n",
48 		    insn_bytes[0], insn_bytes[1]);
49 
50 	vcpu_regs_get(vcpu, &regs);
51 	regs.rip += 2;
52 	vcpu_regs_set(vcpu, &regs);
53 }
54 
55 #endif /* !SELFTEST_KVM_FLDS_EMULATION_H */
56