From: Muli Ben-Yehuda <muli@il.ibm.com>
To: Avi Kivity <avi@qumranet.com>
Cc: Amit Shah <amit.shah@qumranet.com>,
Byron Stanoszek <bstanoszek@comtime.com>,
kvm@vger.kernel.org
Subject: Re: VT-d support for device assignment
Date: Fri, 22 Aug 2008 22:09:17 +0300 [thread overview]
Message-ID: <20080822190917.GK6885@il.ibm.com> (raw)
In-Reply-To: <48AF075C.7050904@qumranet.com>
On Fri, Aug 22, 2008 at 09:37:16PM +0300, Avi Kivity wrote:
> > Actually, with direct-mmio we bypass QEMU and get a nice boost in
> > performance, and it should be possible to bypass QEMU for (most)
> > PIO's too.
>
> Since there is no pio remapping, there's no way to ensure there's a
> free pio range where the guest maps its ports.
True, and we also need to trap pio's for things like configuration
space accesses that the host needs to know about, such as BAR
re-mappings. Hence my (parenthetical) comment with regards to
"most". It's not at all clear that the gain will be worth the
complexity to decide which pio's to trap and which to let through
directly.
Cheers,
Muli
--
Workshop on I/O Virtualization (WIOV '08)
Co-located with OSDI '08, Dec 2008, San Diego, CA
http://www.usenix.org/wiov08
next prev parent reply other threads:[~2008-08-22 19:09 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-22 7:10 VT-d support for device assignment Amit Shah
2008-08-22 7:10 ` [PATCH] VT-d: changes to support KVM Amit Shah
2008-08-22 7:10 ` [PATCH] KVM: Device Assignment with VT-d Amit Shah
2008-08-23 16:21 ` [PATCH] VT-d: changes to support KVM Jesse Barnes
2008-08-22 13:54 ` VT-d support for device assignment Byron Stanoszek
2008-08-22 15:32 ` Amit Shah
2008-08-22 18:29 ` Muli Ben-Yehuda
2008-08-22 18:37 ` Avi Kivity
2008-08-22 19:09 ` Muli Ben-Yehuda [this message]
2008-08-22 16:08 ` Muli Ben-Yehuda
2008-08-22 18:12 ` Avi Kivity
2008-08-22 18:23 ` Muli Ben-Yehuda
2008-08-22 18:21 ` Avi Kivity
2008-08-22 18:28 ` Muli Ben-Yehuda
2008-08-23 9:12 ` Amit Shah
2008-08-23 9:33 ` Avi Kivity
2008-08-23 9:49 ` Amit Shah
2008-08-24 10:01 ` Avi Kivity
2008-08-23 9:50 ` Muli Ben-Yehuda
2008-08-23 9:55 ` Muli Ben-Yehuda
2008-08-24 10:02 ` Avi Kivity
2008-08-23 9:57 ` Muli Ben-Yehuda
2008-08-23 10:25 ` Amit Shah
2008-08-23 10:40 ` Muli Ben-Yehuda
2008-08-23 11:11 ` Amit Shah
2008-08-23 12:11 ` Muli Ben-Yehuda
2008-08-23 14:01 ` Amit Shah
2008-09-01 13:08 ` Joerg Roedel
-- strict thread matches above, loose matches on Subject: below --
2008-09-09 15:37 Amit Shah
2008-09-14 0:46 ` Avi Kivity
2008-09-23 18:57 ` Jesse Barnes
2008-09-09 14:44 Amit Shah
2008-09-09 13:50 Han, Weidong
2008-08-26 8:55 Amit Shah
2008-08-26 9:10 ` Avi Kivity
2008-08-26 14:11 ` Amit Shah
2008-08-26 14:38 ` Avi Kivity
2008-08-21 11:10 Ben-Ami Yassour
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