From: Marcelo Tosatti <mtosatti@redhat.com>
To: Zachary Amsden <zamsden@redhat.com>
Cc: kvm@vger.kernel.org, Avi Kivity <avi@redhat.com>,
Glauber Costa <glommer@redhat.com>,
linux-kernel@vger.kernel.org
Subject: Re: [KVM TSC trapping / migration 2/2] Add TSC KHZ MSR
Date: Fri, 7 Jan 2011 08:48:59 -0200 [thread overview]
Message-ID: <20110107104859.GA12056@amt.cnet> (raw)
In-Reply-To: <1294308645-31113-3-git-send-email-zamsden@redhat.com>
On Thu, Jan 06, 2011 at 12:10:45AM -1000, Zachary Amsden wrote:
> Use an MSR to allow "soft" migration to hosts which do not support
> TSC trapping. Rather than make this a required element of any
> migration protocol, we allow the TSC rate to be exported as a data
> field (useful in its own right), but we also allow a one time write
> of the MSR during VM creation. The result is that for the common
> use case, no protocol change is required to communicate TSC rate
> to the receiving host.
Migration to hosts which do not support the feature can be achieved by
saving/restoring the TSC rate + flags in a subsection. A subsection
seems more appropriate than an MSR for this.
> This allows administrative tools to configure migration policy
> as they see appropriate. Rather than dictate this policy with the
> KVM implementation, we properly allow migration to hosts which both
> do and do not support setting of the TSC rate on the receiving end.
> If it is wished to not support migration to a host which lacks
> support for the TSC rate feature, that can be coordinated externally.
>
> Signed-off-by: Zachary Amsden <zamsden@redhat.com>
next prev parent reply other threads:[~2011-01-07 10:48 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-06 10:10 KVM TSC trapping Zachary Amsden
2011-01-06 10:10 ` [KVM TSC trapping / migration 1/2] Add TSC trapping for SVM and VMX Zachary Amsden
2011-01-06 10:10 ` Zachary Amsden
2011-01-06 10:41 ` Alexander Graf
2011-01-06 11:30 ` Zachary Amsden
2011-01-06 11:38 ` Alexander Graf
2011-01-06 20:24 ` Zachary Amsden
2011-01-06 22:38 ` Alexander Graf
2011-01-07 3:10 ` Zachary Amsden
2011-01-06 11:32 ` Avi Kivity
2011-01-06 20:03 ` Zachary Amsden
2011-01-07 11:23 ` Marcelo Tosatti
2011-01-09 8:05 ` Zachary Amsden
2011-01-10 11:52 ` Joerg Roedel
2011-01-06 10:10 ` [KVM TSC trapping / migration 2/2] Add TSC KHZ MSR Zachary Amsden
2011-01-06 10:34 ` Alexander Graf
2011-01-06 11:27 ` Zachary Amsden
2011-01-06 11:40 ` Alexander Graf
2011-01-06 20:34 ` Zachary Amsden
2011-01-07 10:48 ` Marcelo Tosatti [this message]
2011-01-07 20:44 ` Zachary Amsden
2011-01-10 13:50 ` Marcelo Tosatti
2011-01-14 11:00 ` Juan Quintela
2011-01-18 15:47 ` Zachary Amsden
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