From: Avi Kivity <avi@redhat.com>
To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>, kvm <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [PATCH v2][uq/master] kvm: x86: Save/restore FPU OP, IP and DP
Date: Sun, 19 Jun 2011 15:58:53 +0300 [thread overview]
Message-ID: <4DFDF28D.3030206@redhat.com> (raw)
In-Reply-To: <4DF8B0E6.1080806@siemens.com>
On 06/15/2011 04:17 PM, Jan Kiszka wrote:
> These FPU states are properly maintained by KVM but not yet by TCG. So
> far we unconditionally set them to 0 in the guest which may cause
> state corruptions, though not with modern guests.
>
> To avoid breaking backward migration, use a conditional subsection that
> is only written if any of the three fields is non-zero. The guest's
> FNINIT clears them frequently, and cleared IA32_MISC_ENABLE MSR[2]
> reduces the probability of non-zero values further so that this
> subsection is not expected to restrict migration in any common scenario.
Thanks, applied to uq/master. A test migration showed that the
subsection in fact did not show up.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-06-19 12:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-11 9:23 [Qemu-devel] [PATCH][uq/master] kvm: x86: Save/restore FPU OP, IP and DP Jan Kiszka
2011-06-13 8:45 ` Avi Kivity
2011-06-14 6:10 ` Jan Kiszka
2011-06-14 8:23 ` Avi Kivity
2011-06-14 8:28 ` Jan Kiszka
2011-06-15 9:10 ` Avi Kivity
2011-06-15 10:20 ` Jan Kiszka
2011-06-15 10:39 ` Jan Kiszka
2011-06-15 11:26 ` Avi Kivity
2011-06-15 11:32 ` Jan Kiszka
2011-06-15 11:33 ` Avi Kivity
2011-06-15 11:45 ` Jan Kiszka
2011-06-15 13:17 ` [Qemu-devel] [PATCH v2][uq/master] " Jan Kiszka
2011-06-16 9:42 ` Christophe Fergeau
2011-06-19 12:58 ` Avi Kivity [this message]
2011-06-16 9:35 ` [Qemu-devel] [PATCH][uq/master] " Christophe Fergeau
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