> On 28 Aug 2019, at 0:40, Sean Christopherson <sean.j.christopherson@xxxxxxxxx> wrote:
>
> Immediately inject a #GP when VMware emulation fails and return
> EMULATE_DONE instead of propagating EMULATE_FAIL up the stack. This
> helps pave the way for removing EMULATE_FAIL altogether.
>
> Rename EMULTYPE_VMWARE to EMULTYPE_VMWARE_GP to document that the x86
> emulator is called to handle VMware #GP interception, e.g. why a #GP
> is injected on emulation failure for EMULTYPE_VMWARE_GP.
>
> Drop EMULTYPE_NO_UD_ON_FAIL as a standalone type. The "no #UD on fail"
> is used only in the VMWare case and is obsoleted by having the emulator
> itself reinject #GP.
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_host.h | 3 +--
> arch/x86/kvm/svm.c | 10 ++--------
> arch/x86/kvm/vmx/vmx.c | 10 ++--------
> arch/x86/kvm/x86.c | 14 +++++++++-----
> 4 files changed, 14 insertions(+), 23 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 44a5ce57a905..d1d5b5ca1195 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -1318,8 +1318,7 @@ enum emulation_result {
> #define EMULTYPE_TRAP_UD (1 << 1)
> #define EMULTYPE_SKIP (1 << 2)
> #define EMULTYPE_ALLOW_RETRY (1 << 3)
> -#define EMULTYPE_NO_UD_ON_FAIL (1 << 4)
> -#define EMULTYPE_VMWARE (1 << 5)
> +#define EMULTYPE_VMWARE_GP (1 << 5)
> 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);
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 7242142573d6..c4b72db48bc5 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -2768,7 +2768,6 @@ static int gp_interception(struct vcpu_svm *svm)
> {
> struct kvm_vcpu *vcpu = &svm->vcpu;
> u32 error_code = svm->vmcb->control.exit_info_1;
> - int er;
>
> WARN_ON_ONCE(!enable_vmware_backdoor);
>
> @@ -2780,13 +2779,8 @@ static int gp_interception(struct vcpu_svm *svm)
> kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
> return 1;
> }
> - er = kvm_emulate_instruction(vcpu,
> - EMULTYPE_VMWARE | EMULTYPE_NO_UD_ON_FAIL);
> - if (er == EMULATE_USER_EXIT)
> - return 0;
> - else if (er != EMULATE_DONE)
> - kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
> - return 1;
> + return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP) !=
> + EMULATE_USER_EXIT;
> }
>
> static bool is_erratum_383(void)
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 8a65e1122376..c6ba452296e3 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -4492,7 +4492,6 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
> u32 intr_info, ex_no, error_code;
> unsigned long cr2, rip, dr6;
> u32 vect_info;
> - enum emulation_result er;
>
> vect_info = vmx->idt_vectoring_info;
> intr_info = vmx->exit_intr_info;
> @@ -4519,13 +4518,8 @@ static int handle_exception_nmi(struct kvm_vcpu *vcpu)
> kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
> return 1;
> }
> - er = kvm_emulate_instruction(vcpu,
> - EMULTYPE_VMWARE | EMULTYPE_NO_UD_ON_FAIL);
> - if (er == EMULATE_USER_EXIT)
> - return 0;
> - else if (er != EMULATE_DONE)
> - kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
> - return 1;
> + return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP) !=
> + EMULATE_USER_EXIT;
> }
>
> /*
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index fe847f8eb947..228ca71d5b01 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -6210,8 +6210,10 @@ static int handle_emulation_failure(struct kvm_vcpu *vcpu, int emulation_type)
> ++vcpu->stat.insn_emulation_fail;
> trace_kvm_emulate_insn_failed(vcpu);
>
> - if (emulation_type & EMULTYPE_NO_UD_ON_FAIL)
> - return EMULATE_FAIL;
> + if (emulation_type & EMULTYPE_VMWARE_GP) {
> + kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
> + return EMULATE_DONE;
> + }
>
> kvm_queue_exception(vcpu, UD_VECTOR);
>
> @@ -6543,9 +6545,11 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
> }
> }
>
> - if ((emulation_type & EMULTYPE_VMWARE) &&
> - !is_vmware_backdoor_opcode(ctxt))
> - return EMULATE_FAIL;
> + if ((emulation_type & EMULTYPE_VMWARE_GP) &&
> + !is_vmware_backdoor_opcode(ctxt)) {
> + kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
> + return EMULATE_DONE;
> + }
>
> if (emulation_type & EMULTYPE_SKIP) {
> kvm_rip_write(vcpu, ctxt->_eip);
> --
> 2.22.0
>
