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

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This patch reproduces for nSVM the change that was made for nVMX in
commit b5861e5cf2 ("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: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Paolo Bonzini 2020-03-04 17:05:44 -05:00
parent b518ba9fa6
commit 78f2145c4d
1 changed files with 18 additions and 0 deletions
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18
arch/x86/kvm/svm.c
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@ -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);
}