Commit 78f2145c authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: nSVM: avoid loss of pending IRQ/NMI before entering L2 



This patch reproduces for nSVM the change that was made for nVMX in
commit b5861e5c ("KVM: nVMX: Fix loss of pending IRQ/NMI before
entering L2").  While I do not have a test that breaks without it, I
cannot see why it would not be necessary since all events are unblocked
by VMRUN's setting of GIF back to 1.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent b518ba9f

arch/x86/kvm/svm.c

+18 −0
Original line number Diff line number Diff line
@@ -3576,6 +3576,10 @@ static bool nested_vmcb_checks(struct vmcb *vmcb) 
static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,

				 struct vmcb *nested_vmcb, struct kvm_host_map *map)

{

	bool evaluate_pending_interrupts =

		is_intercept(svm, INTERCEPT_VINTR) ||

		is_intercept(svm, INTERCEPT_IRET);



	if (kvm_get_rflags(&svm->vcpu) & X86_EFLAGS_IF)

		svm->vcpu.arch.hflags |= HF_HIF_MASK;

	else
@@ -3662,7 +3666,21 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, 


	svm->nested.vmcb = vmcb_gpa;



	/*

	 * If L1 had a pending IRQ/NMI before executing VMRUN,

	 * which wasn't delivered because it was disallowed (e.g.

	 * interrupts disabled), L0 needs to evaluate if this pending

	 * event should cause an exit from L2 to L1 or be delivered

	 * directly to L2.

	 *

	 * Usually this would be handled by the processor noticing an

	 * IRQ/NMI window request.  However, VMRUN can unblock interrupts

	 * by implicitly setting GIF, so force L0 to perform pending event

	 * evaluation by requesting a KVM_REQ_EVENT.

	 */

	enable_gif(svm);

	if (unlikely(evaluate_pending_interrupts))

		kvm_make_request(KVM_REQ_EVENT, &svm->vcpu);



	mark_all_dirty(svm->vmcb);

}

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