From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexander Graf <agraf@suse.de>, Mark Burton <mark.burton@greensocs.com>
Cc: mttcg@listserver.greensocs.com,
"Peter Maydell" <peter.maydell@linaro.org>,
"KONRAD Frédéric" <fred.konrad@greensocs.com>,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Lluís Vilanova" <vilanova@ac.upc.edu>
Subject: Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*.
Date: Thu, 18 Dec 2014 17:55:21 +0100 [thread overview]
Message-ID: <549306F9.2010505@redhat.com> (raw)
In-Reply-To: <5492ED45.5040300@suse.de>
On 18/12/2014 16:05, Alexander Graf wrote:
> Yeah, the semantics should be tied to what TM would give you. We can
> always be more safe than TM in our fallback implementation, but I
> wouldn't want to see semantic optimizations tied to the MMIO
> implementation put in.
>
> This is mostly theory though, try to write the code and see where things
> fall apart, then we'll be in a much better position to rationalize on
> where to do things differently.
Yeah, this is why I think LL/SC ops for TCG are more interesting and
important than CMPXCHG. Also because x86 doesn't have just CMPXCHG, it
also has XADD which you'd have to implement anyway as a LL/SC or CMPXCHG
loop, so CMPXCHG doesn't get you all the way.
Paolo
next prev parent reply other threads:[~2014-12-18 16:55 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-16 9:13 [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_* fred.konrad
2014-12-16 9:31 ` Paolo Bonzini
2014-12-16 9:36 ` Frederic Konrad
2014-12-16 9:49 ` Paolo Bonzini
2014-12-16 9:54 ` Frederic Konrad
2014-12-16 16:37 ` Peter Maydell
2014-12-17 10:27 ` Frederic Konrad
2014-12-17 10:28 ` Alexander Graf
2014-12-17 10:31 ` Mark Burton
2014-12-17 10:45 ` Alexander Graf
2014-12-17 11:12 ` Mark Burton
2014-12-17 11:18 ` Alexander Graf
2014-12-17 11:25 ` Paolo Bonzini
2014-12-17 11:36 ` Peter Maydell
2014-12-17 16:17 ` Mark Burton
2014-12-17 16:27 ` Peter Maydell
2014-12-17 16:29 ` Mark Burton
2014-12-17 16:39 ` Peter Maydell
2014-12-17 16:51 ` Peter Maydell
2014-12-18 9:12 ` Mark Burton
2014-12-18 12:24 ` Alexander Graf
2014-12-18 12:35 ` Dr. David Alan Gilbert
2014-12-18 13:28 ` Paolo Bonzini
2014-12-18 13:56 ` Mark Burton
2014-12-18 14:20 ` Mark Burton
2014-12-18 14:44 ` Alexander Graf
2014-12-18 14:51 ` Mark Burton
2014-12-18 15:05 ` Alexander Graf
2014-12-18 15:09 ` Mark Burton
2014-12-18 16:55 ` Paolo Bonzini [this message]
2014-12-17 15:52 ` Mark Burton
2014-12-17 16:20 ` Dr. David Alan Gilbert
2014-12-17 11:19 ` Peter Maydell
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