From: Tim Deegan <tim@xen.org>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: xen-devel@lists.xensource.com, keir@xen.org, jbeulich@suse.com
Subject: Re: [PATCH 3 of 4] VIOAPIC: Emulate a version 0x20 IOAPIC
Date: Wed, 8 Feb 2012 17:05:15 +0000 [thread overview]
Message-ID: <20120208170515.GA71900@ocelot.phlegethon.org> (raw)
In-Reply-To: <79bc45a90933c6ecf226.1328719538@andrewcoop.uk.xensource.com>
At 16:45 +0000 on 08 Feb (1328719538), Andrew Cooper wrote:
> Currently, hvm emulates a version 0x11 IOAPIC. However, depending on
> the HVM guests {IO,L}APIC setup, it may take fewer traps into Xen by
> directly using the VIOAPIC EOI register present in version 0x20,
> rather than resorting to the legacy method of flipping the trigger
> mode for the relevent RTE.
>
> Currently, all required functionality is already present in the code,
> except that it is covered by VIOAPIC_IS_IOSAPIC which is never defined.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
This probably ought to introduce a hvm save record to say which kind of
IOAPIC the VM was booted with, so that after a live migration the OS
doesn't get confused. :(
It seems unlikely that any OSes rely on the IOAPIC version (and the
behaviour of that register) being static after boot, but better safe
than sorry - there might be some confusion in resume from S3 or similar.
Tim.
next prev parent reply other threads:[~2012-02-08 17:05 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-08 16:45 [PATCH 0 of 4] Prune outdated/impossible preprocessor symbols, and update VIOAPIC emulation Andrew Cooper
2012-02-08 16:45 ` [PATCH 1 of 4] CONFIG: remove CONFIG_SMP #ifdefs Andrew Cooper
2012-02-08 17:22 ` Andrew Cooper
2012-02-09 10:54 ` Jan Beulich
2012-02-09 11:51 ` Andrew Cooper
2012-02-09 14:56 ` Jan Beulich
2012-02-08 16:45 ` [PATCH 2 of 4] CONFIG: remove smp barrier definitions Andrew Cooper
2012-02-09 10:49 ` Jan Beulich
2012-02-09 12:42 ` Keir Fraser
2012-02-08 16:45 ` [PATCH 3 of 4] VIOAPIC: Emulate a version 0x20 IOAPIC Andrew Cooper
2012-02-08 17:05 ` Tim Deegan [this message]
2012-02-08 9:12 ` Keir Fraser
2012-02-08 17:13 ` Andrew Cooper
2012-02-08 16:45 ` [PATCH 4 of 4] CONFIG: remove #ifdef __ia64__ from the x86 arch tree Andrew Cooper
2012-02-08 17:24 ` Andrew Cooper
2012-02-09 11:03 ` Jan Beulich
2012-02-09 11:52 ` Andrew Cooper
2012-02-09 13:08 ` Andrew Cooper
2012-02-09 14:58 ` Jan Beulich
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