From: David Woodhouse <dwmw2@infradead.org>
To: Paul Durrant <Paul.Durrant@citrix.com>,
"xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: Eslam Elnikety <elnikety@amazon.de>,
Andrew Cooper <Andrew.Cooper3@citrix.com>,
Shan Haitao <haitao.shan@intel.com>,
Jan Beulich <jbeulich@suse.com>
Subject: Re: [PATCH v2] x86/hvm: re-work viridian APIC assist code
Date: Wed, 05 Sep 2018 11:45:00 +0100 [thread overview]
Message-ID: <1536144300.31549.63.camel@infradead.org> (raw)
In-Reply-To: <c8285b35d7454faeb8bae5d558807522@AMSPEX02CL03.citrite.net>
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On Wed, 2018-09-05 at 10:40 +0000, Paul Durrant wrote:
>
> Actually the neatest approach would be to get information into the
> vlapic code as to whether APIC assist is suitable for the given
> vector so that the code there can selectively enable it, and then Xen
> would know it was safe to avoid fully emulating an EOI for anything
> that did have assist enabled.
I'm not sure I understand why an assisted EOI should be any different
from "normal" EOI.
The global lock and indirect function calls and all that stuff that
hvm_dpci_msi_eoi() does are *expensive*, for a rare case.
Why not bypass all that when it's not needed, for "normal" EOI and
APIC-assisted EOI alike? Why have a distinction between the two?
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next prev parent reply other threads:[~2018-09-05 10:45 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-18 15:10 [PATCH v2] x86/hvm: re-work viridian APIC assist code Paul Durrant
2018-01-18 16:21 ` Jan Beulich
2018-01-18 16:27 ` Paul Durrant
2018-08-24 23:38 ` David Woodhouse
2018-09-03 10:12 ` Paul Durrant
2018-09-04 20:31 ` David Woodhouse
2018-09-05 9:36 ` Paul Durrant
2018-09-05 9:40 ` David Woodhouse
2018-09-05 9:43 ` Paul Durrant
2018-09-05 10:40 ` Paul Durrant
2018-09-05 10:45 ` David Woodhouse [this message]
2018-09-05 10:48 ` Paul Durrant
2020-08-11 13:25 ` [Xen-devel] " David Woodhouse
2020-08-12 13:43 ` Roger Pau Monné
2020-08-13 8:10 ` Paul Durrant
2020-08-13 9:45 ` Roger Pau Monné
2020-08-14 14:13 ` David Woodhouse
2020-08-14 14:41 ` Roger Pau Monné
2020-08-19 7:12 ` Jan Beulich
2020-08-19 8:26 ` Roger Pau Monné
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