From: Richard Henderson <rth@twiddle.net>
To: Blue Swirl <blauwirbel@gmail.com>
Cc: aurelien@aurel32.net, qemu-devel@nongnu.org,
Nathan Froyd <froydnj@codesourcery.com>
Subject: Re: [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly.
Date: Thu, 25 Mar 2010 11:19:40 -0700 [thread overview]
Message-ID: <4BABA93C.9010305@twiddle.net> (raw)
In-Reply-To: <f43fc5581003251040q1ebe12c3u124baf80c9a92cce@mail.gmail.com>
On 03/25/2010 10:40 AM, Blue Swirl wrote:
> Sparc V8 has two atomic instructions, ldstub and swap.
I know -- but not the CAS operation being discussed here.
As I think about this more and more, the Real Problem is
not with the CAS, but with the memory ordering requirements
of the guest vs the memory ordering of the host. It's easy
to implement things on x86, because of the host's strict
memory ordering. It would be much more difficult to properly
emulate x86 on a relaxed memory ordering host. We'd need to
insert barriers between pairs of qemu_{ld,st} operations.
I may give this some proper thinking this weekend.
r~
next prev parent reply other threads:[~2010-03-25 18:20 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-25 0:24 [Qemu-devel] [PATCH 00/10, v3] target-alpha improvements Richard Henderson
2010-03-12 18:31 ` [Qemu-devel] [PATCH 01/10] target-alpha: Add flags markups to helpers.h Richard Henderson
2010-03-12 19:22 ` [Qemu-devel] [PATCH 02/10] target-alpha: Implement cpys{, n, e} inline Richard Henderson
2010-03-15 14:49 ` [Qemu-devel] [PATCH 03/10] target-alpha: Implement rs/rc properly Richard Henderson
2010-03-15 15:38 ` [Qemu-devel] [PATCH 05/10] target-alpha: Implement cvtlq inline Richard Henderson
2010-03-16 20:04 ` [Qemu-devel] [PATCH 06/10] target-alpha: Use setcond for int comparisons Richard Henderson
2010-03-16 21:44 ` [Qemu-devel] [PATCH 07/10] target-alpha: Use non-inverted arguments to gen_{f}cmov Richard Henderson
2010-03-16 22:10 ` [Qemu-devel] [PATCH 08/10] target-alpha: Emit goto_tb opcodes Richard Henderson
2010-03-19 22:55 ` [Qemu-devel] [PATCH 04/10] target-alpha: Implement cvtql inline Richard Henderson
2010-03-25 0:11 ` [Qemu-devel] [PATCH 09/10] target-alpha: Implement load-locked/store-conditional properly Richard Henderson
2010-03-25 13:39 ` Nathan Froyd
2010-03-25 15:46 ` Richard Henderson
2010-03-25 16:06 ` Nathan Froyd
2010-03-25 16:29 ` Richard Henderson
2010-03-25 16:42 ` Nathan Froyd
2010-03-25 16:50 ` Richard Henderson
2010-03-25 17:40 ` Blue Swirl
2010-03-25 18:19 ` Richard Henderson [this message]
2010-03-26 1:55 ` Jamie Lokier
2010-03-26 2:01 ` Jamie Lokier
2010-03-25 0:13 ` [Qemu-devel] [PATCH 10/10] target-alpha: Enable NPTL Richard Henderson
2010-03-26 1:52 ` [Qemu-devel] [PATCH 00/10, v3] target-alpha improvements Jamie Lokier
2010-03-26 13:37 ` Richard Henderson
2010-04-01 13:44 ` Paul Brook
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