Messages in this thread | | | Date | Mon, 13 Dec 2021 14:15:51 +0100 | Subject | Re: [PATCH v2 1/5] KVM: nSVM: deal with L1 hypervisor that intercepts interrupts but lets L2 control EFLAGS.IF | From | Paolo Bonzini <> |
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On 12/13/21 14:07, Maxim Levitsky wrote: >> Right, another case is when CLGI is not trapped and the guest therefore >> runs with GIF=0. I think that means that a similar change has to be >> done in all the *_allowed functions. > > I think that SVM sets real GIF to 1 on VMentry regardless if it is trapped or not.
Yes, the issue is only when CLGI is not trapped (and vGIF is disabled).
> However if not trapped, and neither EFLAGS.IF is trapped, one could enter a guest > that has EFLAGS.IF == 0, then the guest could disable GIF, enable EFLAGS.IF, > and then enable GIF, but then GIF enablement should trigger out interrupt window > VINTR as well.
While GIF=0 you have svm_nmi_blocked returning true and svm_nmi_allowed returning -EBUSY; that's wrong isn't it?
Paolo
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