Commit 72c14e00 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
Browse files

KVM: x86: Formalize blocking of nested pending exceptions 



Capture nested_run_pending as block_pending_exceptions so that the logic
of why exceptions are blocked only needs to be documented once instead of
at every place that employs the logic.

No functional change intended.

Signed-off-by: default avatarSean Christopherson <seanjc@google.com>
Reviewed-by: default avatarMaxim Levitsky <mlevitsk@redhat.com>
Link: https://lore.kernel.org/r/20220830231614.3580124-16-seanjc@google.com


Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent d4963e31

arch/x86/kvm/svm/nested.c

+16 −10
Original line number Diff line number Diff line
@@ -1360,10 +1360,22 @@ static inline bool nested_exit_on_init(struct vcpu_svm *svm) 


static int svm_check_nested_events(struct kvm_vcpu *vcpu)

{

	struct vcpu_svm *svm = to_svm(vcpu);

	bool block_nested_events =

		kvm_event_needs_reinjection(vcpu) || svm->nested.nested_run_pending;

	struct kvm_lapic *apic = vcpu->arch.apic;

	struct vcpu_svm *svm = to_svm(vcpu);

	/*

	 * Only a pending nested run blocks a pending exception.  If there is a

	 * previously injected event, the pending exception occurred while said

	 * event was being delivered and thus needs to be handled.

	 */

	bool block_nested_exceptions = svm->nested.nested_run_pending;

	/*

	 * New events (not exceptions) are only recognized at instruction

	 * boundaries.  If an event needs reinjection, then KVM is handling a

	 * VM-Exit that occurred _during_ instruction execution; new events are

	 * blocked until the instruction completes.

	 */

	bool block_nested_events = block_nested_exceptions ||

				   kvm_event_needs_reinjection(vcpu);



	if (lapic_in_kernel(vcpu) &&

	    test_bit(KVM_APIC_INIT, &apic->pending_events)) {
@@ -1376,13 +1388,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu) 
	}



	if (vcpu->arch.exception.pending) {

		/*

		 * Only a pending nested run can block a pending exception.

		 * Otherwise an injected NMI/interrupt should either be

		 * lost or delivered to the nested hypervisor in the EXITINTINFO

		 * vmcb field, while delivering the pending exception.

		 */

		if (svm->nested.nested_run_pending)

		if (block_nested_exceptions)

                        return -EBUSY;

		if (!nested_exit_on_exception(svm))

			return 0;

arch/x86/kvm/vmx/nested.c

+17 −10
Original line number Diff line number Diff line
@@ -3945,11 +3945,23 @@ static bool nested_vmx_preemption_timer_pending(struct kvm_vcpu *vcpu) 


static int vmx_check_nested_events(struct kvm_vcpu *vcpu)

{

	struct kvm_lapic *apic = vcpu->arch.apic;

	struct vcpu_vmx *vmx = to_vmx(vcpu);

	unsigned long exit_qual;

	bool block_nested_events =

	    vmx->nested.nested_run_pending || kvm_event_needs_reinjection(vcpu);

	struct kvm_lapic *apic = vcpu->arch.apic;

	/*

	 * Only a pending nested run blocks a pending exception.  If there is a

	 * previously injected event, the pending exception occurred while said

	 * event was being delivered and thus needs to be handled.

	 */

	bool block_nested_exceptions = vmx->nested.nested_run_pending;

	/*

	 * New events (not exceptions) are only recognized at instruction

	 * boundaries.  If an event needs reinjection, then KVM is handling a

	 * VM-Exit that occurred _during_ instruction execution; new events are

	 * blocked until the instruction completes.

	 */

	bool block_nested_events = block_nested_exceptions ||

				   kvm_event_needs_reinjection(vcpu);



	if (lapic_in_kernel(vcpu) &&

		test_bit(KVM_APIC_INIT, &apic->pending_events)) {
@@ -3988,15 +4000,10 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu) 
	 * for TSS T flag #DBs).  KVM also doesn't save/restore pending MTF

	 * across SMI/RSM as it should; that needs to be addressed in order to

	 * prioritize SMI over MTF and trap-like #DBs.

	 *

	 * Note that only a pending nested run can block a pending exception.

	 * Otherwise an injected NMI/interrupt should either be

	 * lost or delivered to the nested hypervisor in the IDT_VECTORING_INFO,

	 * while delivering the pending exception.

	 */

	if (vcpu->arch.exception.pending &&

	    !(vmx_get_pending_dbg_trap(vcpu) & ~DR6_BT)) {

		if (vmx->nested.nested_run_pending)

		if (block_nested_exceptions)

			return -EBUSY;

		if (!nested_vmx_check_exception(vcpu, &exit_qual))

			goto no_vmexit;
@@ -4013,7 +4020,7 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu) 
	}



	if (vcpu->arch.exception.pending) {

		if (vmx->nested.nested_run_pending)

		if (block_nested_exceptions)

			return -EBUSY;

		if (!nested_vmx_check_exception(vcpu, &exit_qual))

			goto no_vmexit;