linux-kernel - Re: [PATCH 00/24] KVM: nSVM: event fixes and migration support

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Date:   Wed, 20 May 2020 22:42:11 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     Maxim Levitsky <mlevitsk@...hat.com>, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     vkuznets@...hat.com, Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH 00/24] KVM: nSVM: event fixes and migration support

On 20/05/20 21:24, Maxim Levitsky wrote:
> Patch 24 doesn't apply cleanly on top of kvm/queue, I appplied it manually,
> due to missing KVM_STATE_NESTED_MTF_PENDING bit
> 
> Also patch 22 needes ALIGN_UP which is not on mainline.
> Probably in linux-next?

Just replace it with ALIGN.  (I tested it with memzero_user in
arch/x86/kvm/ for convenience, and the lib/ patch ended up out of sync
with the actual code).

> With these fixes, I don't see #DE exceptions on a nested guest I try to run
> however it still hangs, right around the time it tries to access PS/2 keyboard/mouse.

IIRC you said that the bug appeared with the vintr rework, and then went
from hang to #DE and now back to hang?  And the hang is reported by L2,
not L1?

In order to debug the hang, a good start would be to understand if it
also happens with vgif=0.  This is because with vgif=1 we use VINTR
intercepts even while GIF=0, so the whole thing is a bit more complicated.

Paolo