From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Emilio G. Cota" <cota@braap.org>
Subject: Re: [PATCH 11/35] target/i386: access
 cpu->interrupt_request with atomics
Date: Wed, 19 Sep 2018 11:02:20 -0400
Message-ID: <20180919150220.GA28724@flamenco>
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	<681e812b-43f2-04b2-f015-489b6154fec8@twiddle.net>
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Cc: Paolo Bonzini <pbonzini@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>,
	qemu-devel@nongnu.org, kvm@vger.kernel.org,
	Eduardo Habkost <ehabkost@redhat.com>
To: Richard Henderson <rth@twiddle.net>
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On Tue, Sep 18, 2018 at 14:04:35 -0700, Richard Henderson wrote:
> On 9/17/18 9:30 AM, Emilio G. Cota wrote:
> >      cpu_reset(cs);
> > -    cs->interrupt_request = sipi;
> > +    atomic_mb_set(&cs->interrupt_request, sipi);
> >      memcpy(&env->start_init_save, &save->start_init_save,
> 
> Why does this need a memory barrier?
>
> Anyway, I think a bare mechanical conversion would be best
> for the first patch and then extra barriers added separately
> and with a description of why.

Almost no corresponding read has a barrier so it's hard to
justify this one. I'll drop it.

Thanks,

		Emilio