From: Paolo Bonzini <pbonzini@redhat.com>
To: Roman Kagan <rkagan@virtuozzo.com>,
qemu-devel@nongnu.org, Eduardo Habkost <ehabkost@redhat.com>,
Evgeny Yakovlev <eyakovlev@virtuozzo.com>,
"Denis V . Lunev" <den@openvz.org>
Subject: Re: [Qemu-devel] [PATCH 16/23] hyperv: map overlay pages after updating msrs
Date: Wed, 14 Jun 2017 14:11:56 +0200 [thread overview]
Message-ID: <c6f8c40b-6038-3b3a-e78e-a3ea6bc6fc2b@redhat.com> (raw)
In-Reply-To: <20170614115421.GJ2004@rkaganb.sw.ru>
On 14/06/2017 13:54, Roman Kagan wrote:
>> Why not disable the zeroing for host-initiated MSR writes? This is
>> pretty clearly a KVM bug, we can push it to stable kernels too.
>
> The only problem with this is that QEMU will have no reliable way to
> know if the KVM it runs with has this bug fixed or not. Machines
> without vmbus work and even migrate fine with the current KVM despite
> this bug (the only user of those pages currently is synic timers which
> re-arm themselves and post messages regardless of zeroing). Now
> updating QEMU to a vmbus-enabled version without updating the kernel
> will make the migrations cause guest hangs.
Return 2 from KVM_CHECK_EXTENSION(KVM_CAP_HYPERV_SYNIC)? Then you can
make new QEMU refuse to enable synic if a new kernel is not available.
Paolo
next prev parent reply other threads:[~2017-06-14 12:12 UTC|newest]
Thread overview: 76+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-06 18:19 [Qemu-devel] [PATCH 00/23] hyperv fixes and enhancements Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 01/23] hyperv: add header with protocol definitions Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 02/23] update-linux-headers: prepare for hyperv.h removal Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 03/23] hyperv: set partition-wide MSRs only on first vcpu Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 04/23] hyperv: ensure msrs are inited properly Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 05/23] hyperv: ensure VP index equal to QEMU cpu_index Roman Kagan
2017-06-13 18:57 ` Eduardo Habkost
2017-06-14 11:25 ` Roman Kagan
2017-06-14 11:26 ` Paolo Bonzini
2017-06-14 13:00 ` Igor Mammedov
2017-06-15 12:41 ` Roman Kagan
2017-06-15 13:22 ` Paolo Bonzini
2017-06-15 13:27 ` Igor Mammedov
2017-06-15 16:05 ` Roman Kagan
2017-06-18 15:29 ` Eduardo Habkost
2017-06-14 13:01 ` Eduardo Habkost
2017-06-14 13:11 ` Igor Mammedov
2017-06-14 13:17 ` Paolo Bonzini
2017-06-14 13:22 ` Eduardo Habkost
2017-06-14 13:37 ` Paolo Bonzini
2017-06-14 13:38 ` Igor Mammedov
2017-06-14 13:45 ` Eduardo Habkost
2017-06-14 18:40 ` Roman Kagan
2017-06-14 18:59 ` Eduardo Habkost
2017-06-15 8:26 ` Paolo Bonzini
2017-06-15 11:40 ` Roman Kagan
2017-06-15 11:42 ` Paolo Bonzini
2017-06-15 12:03 ` Roman Kagan
2017-06-14 13:19 ` Eduardo Habkost
2017-06-14 13:00 ` Eduardo Habkost
2017-06-14 13:24 ` Igor Mammedov
2017-06-14 13:35 ` Eduardo Habkost
2017-06-14 15:31 ` Igor Mammedov
2017-06-06 18:19 ` [Qemu-devel] [PATCH 06/23] hyperv: helper to find vcpu by VP index Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 07/23] hyperv_testdev: refactor for readability Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 08/23] hyperv: cosmetic: g_malloc -> g_new Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 09/23] hyperv: synic: only setup ack notifier if there's a callback Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 10/23] hyperv: allow passing arbitrary data to sint ack callback Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 12/23] hyperv: make HvSintRoute reference-counted Roman Kagan
2017-06-14 13:53 ` Eduardo Habkost
2017-06-14 16:23 ` Roman Kagan
2017-06-23 12:44 ` Eduardo Habkost
2017-06-06 18:19 ` [Qemu-devel] [PATCH 13/23] hyperv: qdev-ify SynIC Roman Kagan
2017-06-13 18:34 ` Eduardo Habkost
2017-06-14 9:58 ` Roman Kagan
2017-06-14 12:46 ` Eduardo Habkost
2017-06-14 15:11 ` Roman Kagan
2017-06-14 15:21 ` Eduardo Habkost
2017-06-06 18:19 ` [Qemu-devel] [PATCH 14/23] kvm-all: make async_safe_run_on_cpu safe on kvm too Roman Kagan
2017-06-08 14:47 ` Paolo Bonzini
2017-06-06 18:19 ` [Qemu-devel] [PATCH 15/23] hyperv: make overlay pages for SynIC Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 16/23] hyperv: map overlay pages after updating msrs Roman Kagan
2017-06-14 11:12 ` Paolo Bonzini
2017-06-14 11:54 ` Roman Kagan
2017-06-14 12:11 ` Paolo Bonzini [this message]
2017-06-14 12:41 ` Roman Kagan
2017-06-14 12:46 ` Paolo Bonzini
2017-06-06 18:19 ` [Qemu-devel] [PATCH 17/23] hyperv: add synic message delivery Roman Kagan
2017-06-14 15:08 ` Paolo Bonzini
2017-06-14 15:28 ` Roman Kagan
2017-06-14 15:32 ` Paolo Bonzini
2017-06-14 15:39 ` Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 18/23] hyperv: add synic event flag signaling Roman Kagan
2017-06-14 15:07 ` Paolo Bonzini
2017-06-06 18:19 ` [Qemu-devel] [PATCH 19/23] hyperv: process SIGNAL_EVENT hypercall Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 20/23] hyperv: process POST_MESSAGE hypercall Roman Kagan
2017-06-14 11:19 ` Paolo Bonzini
2017-06-14 14:20 ` Roman Kagan
2017-06-14 14:30 ` Paolo Bonzini
2017-06-06 18:19 ` [Qemu-devel] [PATCH 21/23] hyperv_testdev: add SynIC message and event testmodes Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 22/23] MAINTAINERS: add myself and eyakovlev@ for hyperv* Roman Kagan
2017-06-06 18:19 ` [Qemu-devel] [PATCH 23/23] hyperv: update copyright notices Roman Kagan
[not found] ` <20170606181948.16238-12-rkagan@virtuozzo.com>
2017-06-13 19:02 ` [Qemu-devel] [PATCH 11/23] hyperv: address HvSintRoute by X86CPU pointer Eduardo Habkost
2017-06-14 11:08 ` Paolo Bonzini
2017-06-14 12:14 ` Roman Kagan
2017-06-14 12:17 ` Paolo Bonzini
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