Re: [Qemu-devel] [PATCH for-1.4] *-user: Don't reset X86CPU again

[Andreas Färber]

Am 21.01.2013 16:54, schrieb Igor Mammedov:
> On Sun, 20 Jan 2013 08:39:35 +0100
> Andreas Färber <address@hidden> wrote:
> Subj could be more specific, something along the lines:
>   Fix broken breakpoints duplication for i386-{bds,linux}-user
> 
>> Since commit 65dee38052597b6285eb208125369f01b29ba6c1 (target-i386:
>> move cpu_reset and reset callback to cpu.c) the x86 CPU is reset through
>> cpu_init() but was still reset immediately after in linux-user and
>> bsd-user. Similarly it was reset again in linux-user after cpu_copy(),
>> defeating its very purpose. Clean this up.
>>
>> Fixing the ppc and sparc cases of cpu_copy() and overhauling its
>> implementation is left for another day.
> Before b55a37c98 cpu_reset() was called at the end of cpu_init() and copying
> CPUState/duplicating breakpoints afterwards in cpu_copy() worked, BUT commit
> b4558d7481 breaks it, by positioning cpu_reset() call after copying
> CPUState/duplicating breakpoints. That should break as minimum breakpoints
> handling since they all should be duplicated on all CPUs and cpu_reset()
> deletes them explicitly.
> 
> From my POV patch fixes bug introduced by b4558d7481, Perhaps you should
> update commit message to mention this commit at least and what this patch
> fixes beside cleanups.
> 
> It would be nice though to get confirmation from Blue that all I've said above
> is not total nonsense.

I believe your analysis wrt breakpoints and watchpoints is incorrect
since the memset() in cpu_reset() handlers only goes up to
offset(CPUArchState, breakpoints), i.e. not including the breakpoints.

But as discussed with Peter I've posted a v2 that first fixes the reset
bug and then cleans up the now-superfluous x86 reset.

Regards,
Andreas

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