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Date: Wed, 31 Aug 2011 09:25:11 +0100
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From: Peter Maydell <peter.maydell@linaro.org>
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Subject: Re: [Qemu-devel] [PATCH] pc: Clean up PIC-to-APIC IRQ path
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To: Jan Kiszka <jan.kiszka@web.de>
Cc: Lucas Meneghel Rodrigues <lmr@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, Marcelo Tosatti <mtosatti@redhat.com>, qemu-devel <qemu-devel@nongnu.org>, Blue Swirl <blauwirbel@gmail.com>, Avi Kivity <avi@redhat.com>, Gerd Hoffmann <kraxel@redhat.com>

On 30 August 2011 20:28, Jan Kiszka <jan.kiszka@web.de> wrote:
> Yes, that's the current state. Once we have bidirectional IRQ links in
> place (pushing downward, querying upward - required to skip IRQ routers
> for fast, lockless deliveries), that should change again.

Can you elaborate a bit more on this? I don't think anybody has
proposed links with their own internal state before in the qdev/qom
discussions...

Also a good solid use case for a bidirectional link is worth
discussing because it influences whether we want to make all
links bidi-by-default or try to do it as a special case.

(OTOH your argument does hold for why reset should be two-phase.)

thanks
-- PMM