Re: [Qemu-devel] [PATCH] thread-win32: fix GetThreadContext() permanently fails

[Peter Maydell]

On 23 June 2015 at 11:46, Paolo Bonzini <address@hidden> wrote:
> SuspendThread was pretty much the only way to emulate signals.
> Initially I used SetThreadContext to redirect execution to cpu_signal;
> that was more complicated, but in retrospect it would have avoided the
> problems with memory barriers and with asynchronous SuspendThread.  It
> certainly would have saved the AdaCore people a lot of debugging time. :(
>
> For 2.5, however, I wonder if SuspendThread/ResumeThread is needed at
> all now that cpu_exit doesn't have to undo block chaining anymore.  Even
> on POSIX platforms the signal might not be necessary anymore.

Yeah, I was wondering that too. All we're really doing is setting
three flag variables, so the suspend/resume or signal is just getting
us atomicity of those flag changes. It might be possible to redesign
things a bit to not require the atomicity part.

-- PMM