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Date: Mon, 07 Oct 2013 16:49:38 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] ChrEMU - Virtualization in the Browser
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To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Peter Maydell <peter.maydell@linaro.org>, =?ISO-8859-1?Q?Alex_Benn=E9?= =?ISO-8859-1?Q?e?= <alex.bennee@linaro.org>, qemu-devel <qemu-devel@nongnu.org>, Anthony Liguori <anthony@codemonkey.ws>, Joey Carlini <moocow1452@gmail.com>

Il 25/09/2013 16:02, Stefan Hajnoczi ha scritto:
>>>> >>> I'm pretty sure coroutines would provide difficult to port too.
>>> >>
>>> >> The gthread backend should work since it doesn't use stack-switching.
>> >
>> > ...except that the gthread backend doesn't work for anything
>> > except some nebulous testing scenarios.
> If someone really needs the gthread backend, they can make it work.
> 
> In a NaCl world, you don't have POSIX signals anyway so the signal
> mask issue with the gthread backend is moot.

If you don't have signals, you also don't have a way to interrupt the
VCPU thread.  After all the work on making memory dispatch more
thread-friendly is completed, it shouldn't be _that_ hard to run the TCG
VCPU threads outside the big QEMU lock.  But until that is done, you
need POSIX signals to interrupt the VCPU thread (Windows uses the debug
API instead, which is even worse and probably doesn't have a NaCl
equivalent either).

Paolo