From: Jeremy Fitzhardinge <jeremy@xensource.com>
Date: Wed, 18 Jul 2007 01:37:05 +0000 (-0700)
Subject: xen: event channels
X-Git-Tag: v2.6.23-rc1~498^2~23
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e46cdb66c8fc1c8d61cfae0f219ff47ac4b9d531;p=pandora-kernel.git

xen: event channels

Xen implements interrupts in terms of event channels.  Each guest
domain gets 1024 event channels which can be used for a variety of
purposes, such as Xen timer events, inter-domain events,
inter-processor events (IPI) or for real hardware IRQs.

Within the kernel, we map the event channels to IRQs, and implement
the whole interrupt handling using a Xen irq_chip.

Rather than setting NR_IRQ to 1024 under PARAVIRT in order to
accomodate Xen, we create a dynamic mapping between event channels and
IRQs.  Ideally, Linux will eventually move towards dynamically
allocating per-irq structures, and we can use a 1:1 mapping between
event channels and irqs.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Eric W. Biederman <ebiederm@xmission.com>
---

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