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SubjectRe: [PATCH 0/2] KVM: SVM: Implement check_nested_events for NMI
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Cathy Avery <cavery@redhat.com> writes:

> Moved nested NMI exit to new check_nested_events.
> The second patch fixes the NMI pending race condition that now occurs.
>
> Cathy Avery (2):
> KVM: SVM: Implement check_nested_events for NMI
> KVM: x86: check_nested_events if there is an injectable NMI
>

Not directly related to this series but I just noticed that we have the
following comment in inject_pending_event():

/* try to inject new event if pending */
if (vcpu->arch.exception.pending) {
...
if (vcpu->arch.exception.nr == DB_VECTOR) {
/*
* This code assumes that nSVM doesn't use
* check_nested_events(). If it does, the
* DR6/DR7 changes should happen before L1
* gets a #VMEXIT for an intercepted #DB in
* L2. (Under VMX, on the other hand, the
* DR6/DR7 changes should not happen in the
* event of a VM-exit to L1 for an intercepted
* #DB in L2.)
*/
kvm_deliver_exception_payload(vcpu);
if (vcpu->arch.dr7 & DR7_GD) {
vcpu->arch.dr7 &= ~DR7_GD;
kvm_update_dr7(vcpu);
}
}

kvm_x86_ops.queue_exception(vcpu);
}

As we already implement check_nested_events() on SVM, do we need to do
anything here? CC: Jim who added the guardian (f10c729ff9652).

> arch/x86/kvm/svm/nested.c | 21 +++++++++++++++++++++
> arch/x86/kvm/svm/svm.c | 2 +-
> arch/x86/kvm/svm/svm.h | 15 ---------------
> arch/x86/kvm/x86.c | 15 +++++++++++----
> 4 files changed, 33 insertions(+), 20 deletions(-)

--
Vitaly

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