Re: [Xen-devel] [RFC Patch v3 18/18] x86/hvm: Always set pending event injection when loading VMC[BS] state.

[Tim Deegan <tim@xxxxxxx>]

At 10:06 -0500 on 10 Sep (1410340016), Aravind Gopalakrishnan wrote:
> Hi,
> You mention that this 'fix' is just copied for svm. But you have not 
> seen the problem of "VM_ENTRY_INTR_INFO may be valid" (whose svm 
> equivalent is "vmcb->eventinj.bytes is valid").
> My concern is that we should test colo mode for svm first, since, if the 
> problem is never really seen on svm, then fix may not be _necessary_

I think it's obvious by inspection of the code (and indeed the patch)
that SVM has the equivalent bug.

> At this point, my problems are with test setups. I can help testing 
> scenarios, but as Wen had mentioned, 'colo testing' might be the way to 
> test.
> So, if I can get some pointers to how I can reproduce the issue at hand, 
> then it would be very helpful.
> 
> (Tim had mentioned we could try to simulate it by running a guest that 
> takes lot of faults and save-restore another guest over it. However,
> I am not having much luck following this route. I got a hvm guest to 
> continuously take SW exceptions on all vcpus and tried to save-restore.
> I can't see vmcb->eventinj.bytes containing any valid info.)

Although I think that getting COLO running on SVM is a gret idea, it
shouldn't block acceptance of this fix.  I've attached a program
that tests for the bug.  Run it against any HVM guest (and then
destroy the guest because the test will have corrupted its state).

Cheers,

Tim.

Attachment: injectiontest.c
Description: Text Data

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel