From: Paolo Bonzini <pbonzini@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>,
kvm@vger.kernel.org, qemu-devel <qemu-devel@nongnu.org>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Juan Quintela" <quintela@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>
Subject: Re: [QEMU PATCH v2] kvmclock: advance clock by time window between vm_stop and pre_save
Date: Thu, 10 Nov 2016 18:57:21 +0100 [thread overview]
Message-ID: <7e62defb-dcbe-492d-3c05-056b13d6699a@redhat.com> (raw)
In-Reply-To: <20161110114826.GA28418@amt.cnet>
On 10/11/2016 12:48, Marcelo Tosatti wrote:
> Destination has to run the following logic:
>
> If (source has KVM_CAP_ADVANCE_CLOCK)
> use KVM_GET_CLOCK value
> Else
> read pvclock from guest
>
> To support migration from older QEMU versions which do not have
> KVM_CAP_ADVANCE_CLOCK (or new QEMU versions running on old
> hosts without KVM_CAP_ADVANCE_CLOCK).
>
> I don't see any clean way to give that information, except changing
> the migration format to pass "host: kvm_cap_advance_clock=true/false"
> information.
If you make it only affect new machine types, you could transmit a dummy
clock value such as -1 if the source does not have KVM_CLOCK_TSC_STABLE.
Paolo
next prev parent reply other threads:[~2016-11-10 17:57 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-04 9:43 [QEMU PATCH] kvmclock: advance clock by time window between vm_stop and pre_save Marcelo Tosatti
2016-11-04 12:28 ` Juan Quintela
2016-11-04 12:35 ` Marcelo Tosatti
2016-11-04 14:00 ` Marcelo Tosatti
2016-11-04 15:25 ` Radim Krčmář
2016-11-04 15:33 ` Paolo Bonzini
2016-11-04 15:48 ` Radim Krčmář
2016-11-04 15:57 ` Paolo Bonzini
2016-11-04 17:16 ` Radim Krčmář
2016-11-04 21:29 ` Paolo Bonzini
2016-11-04 21:47 ` Marcelo Tosatti
2016-11-04 22:35 ` Paolo Bonzini
2016-11-07 14:31 ` Roman Kagan
2016-11-07 19:31 ` Marcelo Tosatti
2016-11-04 16:24 ` Marcelo Tosatti
2016-11-04 17:34 ` Radim Krčmář
2016-11-04 18:29 ` Marcelo Tosatti
2016-11-04 20:07 ` Radim Krčmář
2016-11-04 16:04 ` Marcelo Tosatti
2016-11-04 17:07 ` Marcelo Tosatti
2016-11-04 17:39 ` Radim Krčmář
2016-11-04 18:31 ` Marcelo Tosatti
2016-11-07 13:08 ` Dr. David Alan Gilbert
2016-11-04 16:59 ` [QEMU PATCH v2] " Marcelo Tosatti
2016-11-04 18:57 ` Juan Quintela
2016-11-07 15:46 ` Dr. David Alan Gilbert
2016-11-07 19:41 ` Marcelo Tosatti
2016-11-07 20:03 ` Dr. David Alan Gilbert
2016-11-08 0:06 ` Marcelo Tosatti
2016-11-08 10:22 ` Dr. David Alan Gilbert
2016-11-08 13:32 ` Marcelo Tosatti
2016-11-09 19:32 ` Marcelo Tosatti
2016-11-09 16:23 ` Paolo Bonzini
2016-11-09 16:28 ` Dr. David Alan Gilbert
2016-11-09 16:33 ` Paolo Bonzini
2016-11-10 11:48 ` Marcelo Tosatti
2016-11-10 17:57 ` Paolo Bonzini [this message]
2016-11-11 14:23 ` Marcelo Tosatti
2017-02-07 10:02 ` Wanpeng Li
2017-02-07 12:18 ` Marcelo Tosatti
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