[libvirt] [PATCH 6/6] qemu: Make save/restore with USB devices usable

[Daniel P. Berrange]

On Thu, Oct 11, 2012 at 11:42:50AM +0200, Jiri Denemark wrote:
> On Wed, Oct 10, 2012 at 16:40:59 +0100, Daniel P. Berrange wrote:
> > On Tue, Oct 09, 2012 at 02:13:27PM +0200, Jiri Denemark wrote:
> > > @@ -12072,6 +12079,9 @@ virDomainHostdevSourceFormat(virBufferPtr buf,
> > >          policy = virDomainStartupPolicyTypeToString(def->startupPolicy);
> > >          virBufferAsprintf(buf, " startupPolicy='%s'", policy);
> > >      }
> > > +    if (def->source.subsys.u.usb.autoAddress &&
> > > +        (flags & VIR_DOMAIN_XML_MIGRATABLE))
> > > +        virBufferAddLit(buf, " autoAddress='yes'");
> > >      virBufferAddLit(buf, ">\n");
> > >  
> > >      virBufferAdjustIndent(buf, 2);
> > 
> > Do we really need to add a new attribute for this. IMHO if the user
> > has specified a vendor+product, then it is always auto-address, even
> > if they have also given a dev+address.
> 
> We do need it. If both vendor/product and bus/dev are specified, the code
> doesn't try to find the device at different address. See the following code
> snippet from usbDeviceSearch:
> 
>         if ((flags & USB_DEVICE_FIND_BY_VENDOR) &&
>             (found_prod != product || found_vend != vendor))
>             continue;
> 
>         if (flags & USB_DEVICE_FIND_BY_BUS) {
>             if (found_bus != bus || found_devno != devno)
>                 continue;
>             found = true;
>         }
> 
> And it also make sense because if there are more devices with the same
> vendor/product id, we require bus/dev to be configured so that we can assign
> the right device and don't mess with other similar devices. However, if the
> address was autofilled by libvirt, we can try to look at other addresses if
> the device cannot be found at its original address (i.e., it was unplugged and
> plugged again).

Ok, ACK to the patch

Daniel
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