KVM: x86: Remove emulation_result enums, EMULATE_{DONE,FAIL,USER_EXIT}

Deferring emulation failure handling (in some cases) to the caller of
x86_emulate_instruction() has proven fragile, e.g. multiple instances of
KVM not setting run->exit_reason on EMULATE_FAIL, largely due to it
being difficult to discern what emulation types can return what result,
and which combination of types and results are handled where.

Now that x86_emulate_instruction() always handles emulation failure,
i.e. EMULATION_FAIL is only referenced in callers, remove the
emulation_result enums entirely.  Per KVM's existing exit handling
conventions, return '0' and '1' for "exit to userspace" and "resume
guest" respectively.  Doing so cleans up many callers, e.g. they can
return kvm_emulate_instruction() directly instead of having to interpret
its result.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 9 insertions, 13 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 69e53aa3969d..cb7ad362e9b9 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -787,7 +787,7 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu)
 	kvm_rip_write(vcpu, svm->next_rip);
 	svm_set_interrupt_shadow(vcpu, 0);
 
-	return EMULATE_DONE;
+	return 1;
 }
 
 static void svm_queue_exception(struct kvm_vcpu *vcpu)
@@ -2779,8 +2779,7 @@ static int gp_interception(struct vcpu_svm *svm)
 		kvm_queue_exception_e(vcpu, GP_VECTOR, error_code);
 		return 1;
 	}
-	return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP) !=
-						EMULATE_USER_EXIT;
+	return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP);
 }
 
 static bool is_erratum_383(void)
@@ -2878,7 +2877,7 @@ static int io_interception(struct vcpu_svm *svm)
 	string = (io_info & SVM_IOIO_STR_MASK) != 0;
 	in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
 	if (string)
-		return kvm_emulate_instruction(vcpu, 0) == EMULATE_DONE;
+		return kvm_emulate_instruction(vcpu, 0);
 
 	port = io_info >> 16;
 	size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT;
@@ -3885,17 +3884,15 @@ static int task_switch_interception(struct vcpu_svm *svm)
 	    int_type == SVM_EXITINTINFO_TYPE_SOFT ||
 	    (int_type == SVM_EXITINTINFO_TYPE_EXEPT &&
 	     (int_vec == OF_VECTOR || int_vec == BP_VECTOR))) {
-		if (skip_emulated_instruction(&svm->vcpu) == EMULATE_USER_EXIT)
+		if (!skip_emulated_instruction(&svm->vcpu))
 			return 0;
 	}
 
 	if (int_type != SVM_EXITINTINFO_TYPE_SOFT)
 		int_vec = -1;
 
-
-
 	return kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,
-			       has_error_code, error_code) != EMULATE_USER_EXIT;
+			       has_error_code, error_code);
 }
 
 static int cpuid_interception(struct vcpu_svm *svm)
@@ -3916,7 +3913,7 @@ static int iret_interception(struct vcpu_svm *svm)
 static int invlpg_interception(struct vcpu_svm *svm)
 {
 	if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
-		return kvm_emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE;
+		return kvm_emulate_instruction(&svm->vcpu, 0);
 
 	kvm_mmu_invlpg(&svm->vcpu, svm->vmcb->control.exit_info_1);
 	return kvm_skip_emulated_instruction(&svm->vcpu);
@@ -3924,13 +3921,12 @@ static int invlpg_interception(struct vcpu_svm *svm)
 
 static int emulate_on_interception(struct vcpu_svm *svm)
 {
-	return kvm_emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE;
+	return kvm_emulate_instruction(&svm->vcpu, 0);
 }
 
 static int rsm_interception(struct vcpu_svm *svm)
 {
-	return kvm_emulate_instruction_from_buffer(&svm->vcpu,
-					rsm_ins_bytes, 2) == EMULATE_DONE;
+	return kvm_emulate_instruction_from_buffer(&svm->vcpu, rsm_ins_bytes, 2);
 }
 
 static int rdpmc_interception(struct vcpu_svm *svm)
@@ -4719,7 +4715,7 @@ static int avic_unaccelerated_access_interception(struct vcpu_svm *svm)
 		ret = avic_unaccel_trap_write(svm);
 	} else {
 		/* Handling Fault */
-		ret = (kvm_emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE);
+		ret = kvm_emulate_instruction(&svm->vcpu, 0);
 	}
 
 	return ret;