lkml.org 
[lkml]   [2021]   [Dec]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v2 1/5] KVM: nSVM: deal with L1 hypervisor that intercepts interrupts but lets L2 control EFLAGS.IF
From
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

\
 
 \ /
  Last update: 2021-12-13 14:16    [W:0.065 / U:1.648 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site