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From: Keir Fraser <keir.fraser@eu.citrix.com>
To: James Harper <james.harper@bendigoit.com.au>,
	xen-devel@lists.xensource.com
Subject: Re: Multiple IRQ's in HVM for Windows
Date: Sun, 28 Dec 2008 08:39:00 +0000	[thread overview]
Message-ID: <C57CEBA4.2095F%keir.fraser@eu.citrix.com> (raw)
In-Reply-To: <AEC6C66638C05B468B556EA548C1A77D015500F9@trantor>

On 28/12/2008 03:22, "James Harper" <james.harper@bendigoit.com.au> wrote:

>> Yes, that did occur to me. Might be a nice fallback while still
> allowing
>> up
>> to 16 or whatever devices to have their interrupts distributed across
>> VCPUs.
>> The old mechanism does still need to work, so making it a fallback in
> this
>> new mechanism would be probably not too difficult.
> 
> I've been reading up on APIC's, and it appears that (depending on the
> model) they can support up to 64 interrupts. Is the emulated APIC under
> Xen of the 16 interrupt variety?

The IO-APIC has 48 pins, 16 of which are mapped for legacy ISA, so there are
32 non-legacy pins. Actually we could have more, but that creates
backward-compatibility issues now. 32 should be enough for most uses!

 -- Keir

  reply	other threads:[~2008-12-28  8:39 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-12-26  3:29 Multiple IRQ's in HVM for Windows James Harper
2008-12-26  7:32 ` Keir Fraser
2008-12-26 10:15   ` James Harper
2008-12-26 10:36     ` Keir Fraser
2008-12-26 10:54       ` James Harper
2008-12-26 11:00         ` Keir Fraser
2008-12-27  9:19           ` James Harper
2008-12-27  9:31             ` Keir Fraser
2008-12-27  9:35               ` James Harper
2008-12-27  9:57                 ` Keir Fraser
2008-12-27 10:03                   ` James Harper
2008-12-27 10:22                     ` Keir Fraser
2008-12-27 10:28                       ` James Harper
2008-12-27 10:39                         ` Keir Fraser
2008-12-27 11:18                           ` James Harper
2008-12-28  3:22                           ` James Harper
2008-12-28  8:39                             ` Keir Fraser [this message]
2008-12-31 14:57                         ` Ross Philipson

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