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Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*.
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*. |
Date: |
Thu, 18 Dec 2014 17:55:21 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 |
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
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., (continued)
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Mark Burton, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Alexander Graf, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Dr. David Alan Gilbert, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Paolo Bonzini, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Mark Burton, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Mark Burton, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Alexander Graf, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Mark Burton, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Alexander Graf, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Mark Burton, 2014/12/18
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*.,
Paolo Bonzini <=
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Mark Burton, 2014/12/17
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Dr. David Alan Gilbert, 2014/12/17
- Re: [Qemu-devel] [RFC PATCH] target-arm: protect cpu_exclusive_*., Peter Maydell, 2014/12/17