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From: Gerhard Wiesinger <lists@wiesinger.com>
To: Paolo Bonzini <pbonzini@redhat.com>, kvm@vger.kernel.org
Subject: Re: [PATCH] Fixed KVM problems with old DOS programs. Compatibility can be forced by module parameter.
Date: Thu, 5 Nov 2015 17:07:39 +0100	[thread overview]
Message-ID: <563B7ECB.9030504@wiesinger.com> (raw)
In-Reply-To: <563A80F4.6090204@redhat.com>

On 04.11.2015 23:04, Paolo Bonzini wrote:
>
> On 04/11/2015 22:33, Gerhard Wiesinger wrote:
>>> What is the problem you are seeing?  KVM can emulate task switches; the
>>> intercept is set here because of a processor erratum that can mess them
>>> up even though, in theory, AMD supports task switching from guest mode.
>> See old thread:
>> https://lists.nongnu.org/archive/html/qemu-devel/2012-04/msg01506.html
> Can you obtain the traces you were asked for at the time?

./trace-cmd record -b 20000 -e kvm
./trace-cmd report | grep -i task_switch
  qemu-system-x86-6024  [001] 792774.719297: kvm_exit: reason 
task_switch rip 0x4883 info 158 4000000000

But I can't interpret it. But I know my patch works well. Since it is 
just a module parameter it is fully backward compatible by default and 
because of the one liner no side effects are possible. So a intergration 
would be good.

Ciao,
Gerhard


  reply	other threads:[~2015-11-05 16:07 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-04 19:33 [PATCH] Fixed KVM problems with old DOS programs. Compatibility can be forced by module parameter Gerhard Wiesinger
2015-11-04 21:27 ` Paolo Bonzini
2015-11-04 21:33   ` Gerhard Wiesinger
2015-11-04 22:04     ` Paolo Bonzini
2015-11-05 16:07       ` Gerhard Wiesinger [this message]
2015-11-05 16:15         ` Paolo Bonzini
2015-11-05 16:19           ` Paolo Bonzini

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