[libvirt] PATCH: Always reset PCI devices

Daniel P. Berrange berrange at redhat.com
Mon Mar 2 18:27:17 UTC 2009

Mark's patches added a attribute  managed='yes|no' for PCI <hostdev> 
configuration. This allows the caller app to indicate  who is responsible
for attaching/detaching the PCI device from the host drivers. When using
managed=yes, libvirt does it, while using managed=no, the someone else
should do it - typically blacklist the devices in /etc/modprobe.conf

Before launching a guest though the devices need to be reset. Mark made
the reset operation conditional on managed=yes, which was not what I
had intended. libvirtd should always reset the devices so they are in
a sane state before booting, regardless of who manages the host driver
binding. The forthcoming PCI passthrough suppor in the Xen driver will
work in this way - we'll only support managed=no, but XenD will still
always do the reset of devices

I also add a comment to remind us that we should add validation that
the PCI device is not still in use in the non-managed case.


Index: src/qemu_conf.c
RCS file: /data/cvs/libvirt/src/qemu_conf.c,v
retrieving revision 1.132
diff -u -p -u -p -r1.132 qemu_conf.c
--- src/qemu_conf.c	2 Mar 2009 16:40:31 -0000	1.132
+++ src/qemu_conf.c	2 Mar 2009 18:23:07 -0000
@@ -1411,7 +1411,9 @@ int qemudBuildCommandLine(virConnectPtr 
                 pciFreeDevice(conn, dev);
-            }
+            } /* else {
+                XXX validate that non-managed device isn't in use
+            } */
@@ -1421,8 +1423,7 @@ int qemudBuildCommandLine(virConnectPtr 
         virDomainHostdevDefPtr hostdev = vm->def->hostdevs[i];
         pciDevice *dev;
-        if (!hostdev->managed ||
-            hostdev->mode != VIR_DOMAIN_HOSTDEV_MODE_SUBSYS ||
+        if (hostdev->mode != VIR_DOMAIN_HOSTDEV_MODE_SUBSYS ||
             hostdev->source.subsys.type != VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_PCI)

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