[libvirt] [PATCH]: Make Xen VT-d PCI attach/detach work
All, The Xen code for making HVM VT-d PCI passthrough attach and detach is currently not properly working. There are 2 problems: 1) In xenDaemonAttachDevice(), we were always trying to reconfigure a PCI passthrough device, even the first time we added it. This was because the code in virDomainXMLDevID() was not checking xenstore for the existence of the device, and always returning 0 (meaning that the device already existed). 2) In xenDaemonDetachDevice(), we were trying to use "device_destroy" to detach a PCI device. While you would think that is the right method to call, it's actually wrong for PCI devices. In particular, in upstream Xen (and soon in RHEL-5 Xen), device_configure is actually used to destroy a PCI device. The attached patch fixes both of these problems. To fix the attach problem I add a lookup into xenstore to see if the device we are trying to attach already exists. To fix the detach problem I change it so that for PCI detach (only), we use device_configure with the appropriate sxpr to do the detachment. Tested by me on RHEL-5 on a VT-d capable machine, and, in combination with the RHEL-5 xen patch, fixes the problem for me in testing. (note: this solves https://bugzilla.redhat.com/show_bug.cgi?id=546671) Signed-off-by: Chris Lalancette <clalance@redhat.com>
On Fri, Dec 11, 2009 at 05:33:15PM +0100, Chris Lalancette wrote:
All, The Xen code for making HVM VT-d PCI passthrough attach and detach is currently not properly working. There are 2 problems:
1) In xenDaemonAttachDevice(), we were always trying to reconfigure a PCI passthrough device, even the first time we added it. This was because the code in virDomainXMLDevID() was not checking xenstore for the existence of the device, and always returning 0 (meaning that the device already existed).
2) In xenDaemonDetachDevice(), we were trying to use "device_destroy" to detach a PCI device. While you would think that is the right method to call, it's actually wrong for PCI devices. In particular, in upstream Xen (and soon in RHEL-5 Xen), device_configure is actually used to destroy a PCI device.
The attached patch fixes both of these problems. To fix the attach problem I add a lookup into xenstore to see if the device we are trying to attach already exists. To fix the detach problem I change it so that for PCI detach (only), we use device_configure with the appropriate sxpr to do the detachment.
Tested by me on RHEL-5 on a VT-d capable machine, and, in combination with the RHEL-5 xen patch, fixes the problem for me in testing.
(note: this solves https://bugzilla.redhat.com/show_bug.cgi?id=546671)
Signed-off-by: Chris Lalancette <clalance@redhat.com>
Okay, not trivial to debug and test, looks fine to me, ACK, pushed, Daniel -- Daniel Veillard | libxml Gnome XML XSLT toolkit http://xmlsoft.org/ daniel@veillard.com | Rpmfind RPM search engine http://rpmfind.net/ http://veillard.com/ | virtualization library http://libvirt.org/
participants (2)
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Chris Lalancette -
Daniel Veillard