From: Avi Kivity <avi@redhat.com>
To: Andre Przywara <andre.przywara@amd.com>
Cc: kvm@vger.kernel.org
Subject: Re: [PATCH] kvm: always set accessed bit in VMCS segment selectors
Date: Fri, 09 Jan 2009 19:57:13 +0200 [thread overview]
Message-ID: <49678FF9.2040404@redhat.com> (raw)
In-Reply-To: <1231502556706-git-send-email-andre.przywara@amd.com>
Andre Przywara wrote:
> Intel manual 22.3.1.2 demands that the accessed bit (bit 0 in type field)
> must be set when on DS,ES,FS and GS when the selector is usable.
> This fixes cross vendor migration from AMD to Intel.
>
> I am not sure what the real purpose of this check is, so I put this
> in the VMX path and not in the SVM one. If someone has an explanation
> which justifies a move, I am happy to do this.
>
If I understand correctly, loading a segment should set the accessed bit
in the descriptor table (without virtualization there is now way to have
the accessed bit clear in the segment cache), so it looks like the
correct fix is to adjust svm (we already have a couple of similar fixes
there).
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
next prev parent reply other threads:[~2009-01-09 17:56 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-09 12:02 [PATCH] kvm: always set accessed bit in VMCS segment selectors Andre Przywara
2009-01-09 17:57 ` Avi Kivity [this message]
2009-01-09 21:27 ` [PATCH] set accessed bit for VMCB " Andre Przywara
2009-01-10 5:17 ` Amit Shah
2009-01-11 21:39 ` [PATCH] kvm: " Andre Przywara
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