[libvirt] [RFC PATCH] qemu: Add suport for pci-assign.configfd option

[Chris Wright]

* Alex Williamson (alex.williamson at redhat.com) wrote:
> On Wed, 2010-05-19 at 22:34 -0700, Chris Wright wrote:
> > * Alex Williamson (alex.williamson at redhat.com) wrote:
> > > @@ -1378,6 +1420,9 @@ int qemudExtractVersionInfo(const char *qemu,
> > >                            &version, &is_kvm, &kvm_version) == -1)
> > >          goto cleanup2;
> > >  
> > > +    if (flags & QEMUD_CMD_FLAG_DEVICE)
> > > +        qemudParsePCIDeviceStrs(qemu, &flags);
> > > +
> > 
> > looks like this is called early enough for both cmdline and monitor
> > interface
> 
> Yes, it should be.
> 
> > > +    /* XXX don't hard code segment */
> > 
> > You don't need to, just...
> > 
> > > +    if (virAsprintf(&path, "/sys/bus/pci/devices/0000:%02x:%02x.%01x/config",
> >                                                    /
> > s/0000/%04x/ --------------------------------------
> > 
> > > +                    dev->source.subsys.u.pci.bus, dev->source.subsys.u.pci.slot,
> > 
> > and add dev->source.subsys.u.pci.domain 
> 
> Oh good, I meant to look, but obviously forgot.  Fixed.
> 
> > > +                    dev->source.subsys.u.pci.function) < 0) {
> > > +        virReportOOMError();
> > > +        return -1;
> > > +    }
> > > +
> > > +    configfd = open(path, O_RDWR, 0);
> > 
> > Should probably report an open failure to aid debugging.
> 
> Done.
> 
> > > --- a/src/qemu/qemu_driver.c
> > > +++ b/src/qemu/qemu_driver.c
> > > @@ -7567,7 +7567,7 @@ static int qemudDomainAttachHostPciDevice(struct qemud_driver *driver,
> > >          if (qemuDomainPCIAddressEnsureAddr(priv->pciaddrs, &hostdev->info) < 0)
> > >              goto error;
> > >  
> > > -        if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev)))
> > > +        if (!(devstr = qemuBuildPCIHostdevDevStr(hostdev, -1)))
> > 
> > Looks like this is dynamically assigning host PCI device to running guest,
> > we should still be able to pass fd here.  That will complicate the qemu
> > side to be able to accept the fd.
> 
> We could certainly open the file and pass an fd, but I don't know how to
> let qemu make use of it after it's been spawned, so I reverted to
> existing behavior here.  Thanks,

that needs to call to MonitorWriteWithFD or whatever the heck its
called.  and qemu can recv the fd w/ do_getfd path.  however this will
take more work on the qemu side

thanks,
-chris