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KVM: x86: Invert emulation re-execute behavior to make it opt-in

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Re-execution of an instruction after emulation decode failure is
intended to be used only when emulating shadow page accesses.  Invert
the flag to make allowing re-execution opt-in since that behavior is
by far in the minority.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
This commit is contained in:
Sean Christopherson 2018-08-23 13:56:48 -07:00 committed by Radim Krčmář
parent 35be0aded7
commit 8065dbd1ee
3 changed files with 5 additions and 7 deletions
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8
arch/x86/include/asm/kvm_host.h
View File

@ -1238,7 +1238,7 @@ enum emulation_result {
#define EMULTYPE_TRAP_UD (1 << 1)
#define EMULTYPE_SKIP (1 << 2)
#define EMULTYPE_RETRY (1 << 3)
#define EMULTYPE_NO_REEXECUTE (1 << 4)
#define EMULTYPE_ALLOW_REEXECUTE (1 << 4)
#define EMULTYPE_NO_UD_ON_FAIL (1 << 5)
#define EMULTYPE_VMWARE (1 << 6)
int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
@ -1247,15 +1247,13 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, unsigned long cr2,
static inline int emulate_instruction(struct kvm_vcpu *vcpu,
int emulation_type)
{
return x86_emulate_instruction(vcpu, 0,
emulation_type | EMULTYPE_NO_REEXECUTE, NULL, 0);
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, EMULTYPE_NO_REEXECUTE,
insn, insn_len);
return x86_emulate_instruction(vcpu, 0, 0, insn, insn_len);
}
void kvm_enable_efer_bits(u64);

2
arch/x86/kvm/mmu.c
View File

@ -5217,7 +5217,7 @@ static int make_mmu_pages_available(struct kvm_vcpu *vcpu)
int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u64 error_code,
void *insn, int insn_len)
{
int r, emulation_type = EMULTYPE_RETRY;
int r, emulation_type = EMULTYPE_RETRY | EMULTYPE_ALLOW_REEXECUTE;
enum emulation_result er;
bool direct = vcpu->arch.mmu.direct_map;

2
arch/x86/kvm/x86.c
View File

@ -5870,7 +5870,7 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gva_t cr2,
gpa_t gpa = cr2;
kvm_pfn_t pfn;
if (emulation_type & EMULTYPE_NO_REEXECUTE)
if (!(emulation_type & EMULTYPE_ALLOW_REEXECUTE))
return false;
if (!vcpu->arch.mmu.direct_map) {