From: Paolo Bonzini <pbonzini@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>,
aliguori@us.ibm.com, aik@ozlabs.ru, rusty@rustcorp.com.au,
qemu-devel@nongnu.org, agraf@suse.de
Subject: Re: [Qemu-devel] [PATCH] virtio: Make memory barriers be memory barriers
Date: Fri, 02 Sep 2011 08:11:29 +0200 [thread overview]
Message-ID: <4E607391.9070804@redhat.com> (raw)
In-Reply-To: <20110902001128.GN11906@yookeroo.fritz.box>
On 09/02/2011 02:11 AM, David Gibson wrote:
>>> > >Why not limit the change to ppc then?
>> >
>> > Because the bug is masked by the x86 memory model, but it is still
>> > there even there conceptually. It is not really true that x86 does
>> > not need memory barriers, though it doesn't in this case:
>> >
>> > http://bartoszmilewski.wordpress.com/2008/11/05/who-ordered-memory-fences-on-an-x86/
> Not to mention that pcc is not the only non-x86 architecture. I don't
> know all their storage models off hand, but the point is that there is
> a required order to these writes, so there should be a memory barrier.
Indeed, I interpreted Michael's question more as "why not limit the
change to non-x86". I think we should cater to all memory models except
perhaps the Alpha's.
Paolo
next prev parent reply other threads:[~2011-09-02 6:11 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-01 6:09 [Qemu-devel] [PATCH] virtio: Make memory barriers be memory barriers David Gibson
2011-09-01 6:47 ` Paolo Bonzini
2011-09-02 0:08 ` David Gibson
2011-09-02 6:49 ` Paolo Bonzini
2011-09-03 11:53 ` Blue Swirl
2011-09-01 7:37 ` Sasha Levin
2011-09-01 7:38 ` Sasha Levin
2011-09-01 7:56 ` Paolo Bonzini
2011-09-02 0:09 ` David Gibson
2011-09-01 15:30 ` Michael S. Tsirkin
2011-09-01 16:14 ` Paolo Bonzini
2011-09-01 16:34 ` Michael S. Tsirkin
2011-09-01 20:31 ` Paolo Bonzini
2011-09-02 15:45 ` Michael S. Tsirkin
2011-09-03 14:46 ` David Gibson
2011-09-04 9:16 ` Michael S. Tsirkin
2011-09-05 4:43 ` David Gibson
2011-09-05 9:19 ` Michael S. Tsirkin
2011-09-06 3:12 ` David Gibson
2011-09-06 6:55 ` Paolo Bonzini
2011-09-06 9:02 ` David Gibson
2011-09-06 9:28 ` Avi Kivity
2011-09-06 9:35 ` Michael S. Tsirkin
2011-09-06 9:38 ` Paolo Bonzini
2011-09-05 7:41 ` Paolo Bonzini
2011-09-05 8:06 ` Michael S. Tsirkin
2011-09-05 9:42 ` Paolo Bonzini
2011-09-03 16:19 ` Paolo Bonzini
2011-09-04 8:47 ` Michael S. Tsirkin
2011-09-02 0:11 ` David Gibson
2011-09-02 6:11 ` Paolo Bonzini [this message]
2011-09-02 15:57 ` Michael S. Tsirkin
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