diff options
| -rw-r--r-- | arch/x86/kvm/x86.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1eb495e04fd3..8f108131d85d 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -146,6 +146,9 @@ bool __read_mostly enable_vmware_backdoor = false; module_param(enable_vmware_backdoor, bool, S_IRUGO); EXPORT_SYMBOL_GPL(enable_vmware_backdoor); +static bool __read_mostly force_emulation_prefix = false; +module_param(force_emulation_prefix, bool, S_IRUGO); + #define KVM_NR_SHARED_MSRS 16 struct kvm_shared_msrs_global { @@ -4842,9 +4845,20 @@ EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system); int handle_ud(struct kvm_vcpu *vcpu) { + int emul_type = EMULTYPE_TRAP_UD; enum emulation_result er; + char sig[5]; /* ud2; .ascii "kvm" */ + struct x86_exception e; + + if (force_emulation_prefix && + kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, + kvm_get_linear_rip(vcpu), sig, sizeof(sig), &e) == 0 && + memcmp(sig, "\xf\xbkvm", sizeof(sig)) == 0) { + kvm_rip_write(vcpu, kvm_rip_read(vcpu) + sizeof(sig)); + emul_type = 0; + } - er = emulate_instruction(vcpu, EMULTYPE_TRAP_UD); + er = emulate_instruction(vcpu, emul_type); if (er == EMULATE_USER_EXIT) return 0; if (er != EMULATE_DONE) |