From: Hollis Blanchard <hollisb@us.ibm.com>
To: Anthony Liguori <aliguori@us.ibm.com>
Cc: kvm@vger.kernel.org, Avi Kivity <avi@qumranet.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Alexandre Oliva <aoliva@redhat.com>,
Christian Borntraeger <borntraeger@de.ibm.com>
Subject: Re: [PATCH] Add memory clobber to hypercalls (v2)
Date: Fri, 27 Jun 2008 16:05:00 -0500 [thread overview]
Message-ID: <1214600700.28837.8.camel@localhost.localdomain> (raw)
In-Reply-To: <1214504729-16880-1-git-send-email-aliguori@us.ibm.com>
On Thu, 2008-06-26 at 13:25 -0500, Anthony Liguori wrote:
> Hypercalls can modify arbitrary regions of memory. Make sure to indicate this
> in the clobber list. This fixes a hang when using KVM_GUEST kernel built with
> GCC 4.3.0.
>
> This was originally spotted and analyzed by Marcelo.
>
> Since v1, I've also added a "m" constraint for the inputs to the hypercall.
> This was suggested by Christian since it's not entirely clear whether a memory
> clobber will force the data to be in memory before the asm statement. In the
> very least, it helps to be more conservative.
>
> Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Acked-by: Hollis Blanchard <hollisb@us.ibm.com>
--
Hollis Blanchard
IBM Linux Technology Center
next prev parent reply other threads:[~2008-06-27 21:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-06-26 18:25 [PATCH] Add memory clobber to hypercalls (v2) Anthony Liguori
2008-06-27 21:05 ` Hollis Blanchard [this message]
2008-06-28 3:43 ` Avi Kivity
2008-06-30 14:54 ` Hollis Blanchard
2008-06-30 15:59 ` Avi Kivity
2008-07-01 19:02 ` Hollis Blanchard
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