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Commit 1051778f authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Handle emulation failure directly in kvm_task_switch() 



Consolidate the reporting of emulation failure into kvm_task_switch()
so that it can return EMULATE_USER_EXIT.  This helps pave the way for
removing EMULATE_FAIL altogether.

This also fixes a theoretical bug where task switch interception could
suppress an EMULATE_USER_EXIT return.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 738fece4

arch/x86/kvm/svm.c

+2 −9
Original line number Diff line number Diff line
@@ -3892,17 +3892,10 @@ static int task_switch_interception(struct vcpu_svm *svm) 
	if (int_type != SVM_EXITINTINFO_TYPE_SOFT)

		int_vec = -1;



	if (kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,

				has_error_code, error_code) == EMULATE_FAIL)

		goto fail;



	return 1;



fail:

	svm->vcpu.run->exit_reason = KVM_EXIT_INTERNAL_ERROR;

	svm->vcpu.run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;

	svm->vcpu.run->internal.ndata = 0;

	return 0;

	return kvm_task_switch(&svm->vcpu, tss_selector, int_vec, reason,

			       has_error_code, error_code) != EMULATE_USER_EXIT;

}



static int cpuid_interception(struct vcpu_svm *svm)

arch/x86/kvm/vmx/vmx.c

+3 −11
Original line number Diff line number Diff line
@@ -5074,21 +5074,13 @@ static int handle_task_switch(struct kvm_vcpu *vcpu) 
		       type != INTR_TYPE_NMI_INTR))

		skip_emulated_instruction(vcpu);



	if (kvm_task_switch(vcpu, tss_selector,

			    type == INTR_TYPE_SOFT_INTR ? idt_index : -1, reason,

			    has_error_code, error_code) == EMULATE_FAIL) {

		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;

		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;

		vcpu->run->internal.ndata = 0;

		return 0;

	}



	/*

	 * TODO: What about debug traps on tss switch?

	 *       Are we supposed to inject them and update dr6?

	 */



	return 1;

	return kvm_task_switch(vcpu, tss_selector,

			       type == INTR_TYPE_SOFT_INTR ? idt_index : -1,

			       reason, has_error_code, error_code) != EMULATE_USER_EXIT;

}



static int handle_ept_violation(struct kvm_vcpu *vcpu)

arch/x86/kvm/x86.c

+6 −3
Original line number Diff line number Diff line
@@ -8693,9 +8693,12 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index, 


	ret = emulator_task_switch(ctxt, tss_selector, idt_index, reason,

				   has_error_code, error_code);



	if (ret)

		return EMULATE_FAIL;

	if (ret) {

		vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR;

		vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_EMULATION;

		vcpu->run->internal.ndata = 0;

		return EMULATE_USER_EXIT;

	}



	kvm_rip_write(vcpu, ctxt->eip);

	kvm_set_rflags(vcpu, ctxt->eflags);