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-rw-r--r--arch/x86/kvm/x86.c33
1 files changed, 5 insertions, 28 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index dd8016d2efa..8575d85202d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4411,39 +4411,16 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
vcpu->arch.emulate_ctxt.have_exception = false;
vcpu->arch.emulate_ctxt.perm_ok = false;
+ vcpu->arch.emulate_ctxt.only_vendor_specific_insn
+ = emulation_type & EMULTYPE_TRAP_UD;
+
r = x86_decode_insn(&vcpu->arch.emulate_ctxt, insn, insn_len);
trace_kvm_emulate_insn_start(vcpu);
-
- /* Only allow emulation of specific instructions on #UD
- * (namely VMMCALL, sysenter, sysexit, syscall)*/
- if (emulation_type & EMULTYPE_TRAP_UD) {
- if (!c->twobyte)
- return EMULATE_FAIL;
- switch (c->b) {
- case 0x01: /* VMMCALL */
- if (c->modrm_mod != 3 || c->modrm_rm != 1)
- return EMULATE_FAIL;
- break;
- case 0x34: /* sysenter */
- case 0x35: /* sysexit */
- if (c->modrm_mod != 0 || c->modrm_rm != 0)
- return EMULATE_FAIL;
- break;
- case 0x05: /* syscall */
- if (c->modrm_mod != 0 || c->modrm_rm != 0)
- return EMULATE_FAIL;
- break;
- default:
- return EMULATE_FAIL;
- }
-
- if (!(c->modrm_reg == 0 || c->modrm_reg == 3))
- return EMULATE_FAIL;
- }
-
++vcpu->stat.insn_emulation;
if (r) {
+ if (emulation_type & EMULTYPE_TRAP_UD)
+ return EMULATE_FAIL;
if (reexecute_instruction(vcpu, cr2))
return EMULATE_DONE;
if (emulation_type & EMULTYPE_SKIP)