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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>,
	aarcange@redhat.com, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 3/5] x86: fill high bits of mtrr mask
Date: Fri, 17 Jun 2016 14:51:50 +0100	[thread overview]
Message-ID: <20160617135150.GH2273@work-vm> (raw)
In-Reply-To: <4371f52c-335b-95dd-0a50-432d876f0784@redhat.com>

* Paolo Bonzini (pbonzini@redhat.com) wrote:

> Note that the failure mode is pretty brutal since KVM reports an
> internal error right after restarting on the destination, and who knows
> what used to happen before the assertion was introduced.  All MSRs after
> MTRRs would be ignored by KVM!

I think we got lucky because the MTRRs were close to the last MSRs
in the list, there was only some MCG/MCE stuff after it which probably
wouldn't have been missed;  if the MTRR wasn't set I'm guessing someone
would have just had a behaviour that looked like dreadful performance
after migration perhaps?

Dave

> Migrating and checking the configuration complicates the code and,
> because it's only for a warning, doesn't save you from massaging the
> values to make things work.
> 
> Paolo
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

  parent reply	other threads:[~2016-06-17 13:52 UTC|newest]

Thread overview: 73+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-16 17:12 [Qemu-devel] [PATCH 0/5] x86: Physical address limit patches Dr. David Alan Gilbert (git)
2016-06-16 17:12 ` [Qemu-devel] [PATCH 1/5] BIT_RANGE convenience macro Dr. David Alan Gilbert (git)
2016-06-16 17:23   ` Paolo Bonzini
2016-06-16 17:24     ` Dr. David Alan Gilbert
2016-06-16 18:01   ` Peter Maydell
2016-06-16 18:05     ` Paolo Bonzini
2016-06-20 14:11     ` Dr. David Alan Gilbert
2016-06-20 14:17       ` Peter Maydell
2016-06-16 17:12 ` [Qemu-devel] [PATCH 2/5] x86: Mask mtrr mask based on CPU physical address limits Dr. David Alan Gilbert (git)
2016-06-16 19:59   ` Eduardo Habkost
2016-06-17  8:23     ` Dr. David Alan Gilbert
2016-06-17 12:13     ` Paolo Bonzini
2016-06-16 17:12 ` [Qemu-devel] [PATCH 3/5] x86: fill high bits of mtrr mask Dr. David Alan Gilbert (git)
2016-06-16 20:14   ` Eduardo Habkost
2016-06-17  7:47     ` Paolo Bonzini
2016-06-17 12:46       ` Eduardo Habkost
2016-06-17 13:01         ` Paolo Bonzini
2016-06-17 13:41           ` Eduardo Habkost
2016-06-17 14:25             ` Paolo Bonzini
2016-06-17 15:27               ` Eduardo Habkost
2016-06-17 15:29                 ` Paolo Bonzini
2016-06-17 15:35                   ` Eduardo Habkost
2016-06-17 13:51           ` Dr. David Alan Gilbert [this message]
2016-06-17 14:19             ` Paolo Bonzini
2016-06-17  8:53     ` Dr. David Alan Gilbert
2016-06-16 17:12 ` [Qemu-devel] [PATCH 4/5] x86: Allow physical address bits to be set Dr. David Alan Gilbert (git)
2016-06-16 17:26   ` Paolo Bonzini
2016-06-16 18:09     ` Eduardo Habkost
2016-06-16 20:24   ` Eduardo Habkost
2016-06-17  8:15     ` Dr. David Alan Gilbert
2016-06-17  8:43       ` Paolo Bonzini
2016-06-17  9:17         ` Gerd Hoffmann
2016-06-17  9:52           ` Igor Mammedov
2016-06-17 11:20             ` Gerd Hoffmann
2016-06-17 16:20               ` Laszlo Ersek
2016-06-17 16:07             ` Laszlo Ersek
2016-06-19 16:13               ` Marcel Apfelbaum
2016-06-20 10:42                 ` Igor Mammedov
2016-06-20 11:13                   ` Marcel Apfelbaum
2016-06-17  9:37       ` Dr. David Alan Gilbert
2016-06-17  9:54         ` Paolo Bonzini
2016-06-17 13:18       ` Eduardo Habkost
2016-06-17 13:38         ` Paolo Bonzini
2016-06-17 15:19           ` Eduardo Habkost
2016-06-17 15:28             ` Paolo Bonzini
2016-06-17 15:49               ` Eduardo Habkost
2016-06-21 19:44                 ` [Qemu-devel] Default for phys-addr-bits? (was Re: [PATCH 4/5] x86: Allow physical address bits to be set) Eduardo Habkost
2016-06-22 12:41                   ` Paolo Bonzini
2016-06-22 14:24                     ` Andrea Arcangeli
2016-06-22 14:33                       ` Paolo Bonzini
2016-06-22 14:44                         ` Andrea Arcangeli
2016-06-22 14:48                           ` Paolo Bonzini
2016-06-22 15:02                             ` Andrea Arcangeli
2016-06-22 22:44                       ` Michael S. Tsirkin
2016-06-22 23:23                         ` Andrea Arcangeli
2016-06-22 23:45                           ` Michael S. Tsirkin
2016-06-23  8:40                             ` Gerd Hoffmann
2016-06-23 16:38                               ` Michael S. Tsirkin
2016-06-24  5:55                                 ` Gerd Hoffmann
2016-06-24 23:12                                   ` Michael S. Tsirkin
2016-06-29 16:42                               ` Dr. David Alan Gilbert
2016-06-30  6:10                                 ` Gerd Hoffmann
2016-06-30 10:59                                   ` Dr. David Alan Gilbert
2016-06-30 16:14                                     ` Gerd Hoffmann
2016-06-30 17:12                                       ` Dr. David Alan Gilbert
2016-07-01 19:03                                       ` Dr. David Alan Gilbert
2016-06-22 22:40                     ` Michael S. Tsirkin
2016-06-22 23:15                       ` Andrea Arcangeli
2016-06-19  3:36           ` [Qemu-devel] [PATCH 4/5] x86: Allow physical address bits to be set Michael S. Tsirkin
2016-06-20  7:04             ` Paolo Bonzini
2016-06-17 14:24         ` Marcel Apfelbaum
2016-06-16 17:12 ` [Qemu-devel] [PATCH 5/5] x86: Set physical address bits based on host Dr. David Alan Gilbert (git)
2016-06-17  7:25   ` Igor Mammedov

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