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KVM: x86: Unexport x86_emulate_instruction()

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Allowing x86_emulate_instruction() to be called directly has led to
subtle bugs being introduced, e.g. not setting EMULTYPE_NO_REEXECUTE
in the emulation type.  While most of the blame lies on re-execute
being opt-out, exporting x86_emulate_instruction() also exposes its
cr2 parameter, which may have contributed to commit d391f12070
("x86/kvm/vmx: do not use vm-exit instruction length for fast MMIO
when running nested") using x86_emulate_instruction() instead of
emulate_instruction() because "hey, I have a cr2!", which in turn
introduced its EMULTYPE_NO_REEXECUTE bug.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This commit is contained in:
Sean Christopherson
2018-08-23 13:56:53 -07:00
committed by Radim Krčmář
parent 0ce97a2b62
commit c60658d1d9
3 changed files with 18 additions and 15 deletions
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17
arch/x86/include/asm/kvm_host.h
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@@ -1240,20 +1240,9 @@ enum emulation_result {
#define EMULTYPE_ALLOW_RETRY (1 << 3)
#define EMULTYPE_NO_UD_ON_FAIL (1 << 4)
#define EMULTYPE_VMWARE (1 << 5)
int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
int emulation_type, void *insn, int insn_len);
static inline int kvm_emulate_instruction(struct kvm_vcpu *vcpu,
int emulation_type)
{
return x86_emulate_instruction(vcpu, 0, emulation_type, NULL, 0);
}
static inline int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
void *insn, int insn_len)
{
return x86_emulate_instruction(vcpu, 0, 0, insn, insn_len);
}
int kvm_emulate_instruction(struct kvm_vcpu *vcpu, int emulation_type);
int kvm_emulate_instruction_from_buffer(struct kvm_vcpu *vcpu,
void *insn, int insn_len);
void kvm_enable_efer_bits(u64);
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);