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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: kvm-devel <kvm@vger.kernel.org>
Subject: Re: KVM: x86: stop IO emulation cycle if instruction pointer is modified
Date: Mon, 8 Jul 2013 18:16:35 -0300	[thread overview]
Message-ID: <20130708211635.GA11148@amt.cnet> (raw)
In-Reply-To: <20130706074112.GA26728@redhat.com>

On Sat, Jul 06, 2013 at 10:41:12AM +0300, Gleb Natapov wrote:
> On Fri, Jul 05, 2013 at 04:16:55PM -0300, Marcelo Tosatti wrote:
> > 
> > MMIO/PIO emulation should be interrupted if the system is restarted.
> > Otherwise in progress IO emulation continues at the instruction pointer,
> > even after vcpus' IP has been modified by KVM_SET_REGS.
> > 
> > Use IP change as an indicator to reset MMIO/PIO emulation state.
> > 
> Userspace has to return to the kernel to complete pending IO operation.
> This is documented in Documentation/virtual/kvm/api.txt. If this is not
> what program does it is a bug. What userspace you see the problem with?

You're right, this patch should not be necessary.


      reply	other threads:[~2013-07-08 21:23 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-05 19:16 KVM: x86: stop IO emulation cycle if instruction pointer is modified Marcelo Tosatti
2013-07-06  7:41 ` Gleb Natapov
2013-07-08 21:16   ` Marcelo Tosatti [this message]

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