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Date: Thu, 25 Feb 2010 13:50:56 +0100
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Subject: [Qemu-devel] Re: [PATCH v2 2/2] get rid of hostregs_helper.h
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Blue Swirl <blauwirbel@gmail.com>, qemu-devel@nongnu.org

On 02/25/2010 12:40 PM, Michael S. Tsirkin wrote:
> On Thu, Feb 18, 2010 at 11:28:14PM +0200, Blue Swirl wrote:
>>>      /* restore global registers */
>>> -#include "hostregs_helper.h"
>>> +    asm("");
>>> +    env = (void *) saved_env_reg;
>>>
>
> Is this sufficient?
> I see __asm__ __volatile__("": : :"memory") in virtio.
> Is memory clobber implied? What about volatile?

All asms without colons ("old-style") are volatile.  Clobbering memory 
is not necessary since we are only caring about blocking assignments of 
"env", which is by definition in a register (hostregs_helper.h wasn't 
clobbering memory either).

Paolo