Re: [Qemu-devel] [RFC v9 14/18] vfio: improve vfio_pci_hot_reset to support more case

[Chen Fan]

On 06/10/2015 05:24 AM, Alex Williamson wrote:
> On Tue, 2015-06-09 at 11:37 +0800, Chen Fan wrote:
> > the vfio_pci_hot_reset differentiate the single and multi in-used
> > devices for reset. but sometimes we own the group without any devices,
> > that also should support hot reset.
> Nope, did you try it?  It can be done, but the group still needs to be
> connected to a container for isolation.
I'm sorry for that. because I have no such host in hand. but I think if
we can keep connect container for each affected group, we also able
to use this method to do host bus reset.

Thanks,
Chen
> > Signed-off-by: Chen Fan <address@hidden>
> > ---
> >   hw/vfio/pci.c | 11 +++++++++++
> >   1 file changed, 11 insertions(+)
> >
> > diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> > index a4e8658..6507f39 100644
> > --- a/hw/vfio/pci.c
> > +++ b/hw/vfio/pci.c
> > @@ -3398,6 +3398,7 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool 
> > single)
> >           PCIHostDeviceAddress host;
> >           VFIOPCIDevice *tmp;
> >           VFIODevice *vbasedev_iter;
> > +        bool found;
> >   
> >           host.domain = devices[i].segment;
> >           host.bus = devices[i].bus;
> > @@ -3427,6 +3428,7 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool 
> > single)
> >               goto out;
> >           }
> >   
> > +        found = false;
> >           /* Prep dependent devices for reset and clear our marker. */
> >           QLIST_FOREACH(vbasedev_iter, &group->device_list, next) {
> >               if (vbasedev_iter->type != VFIO_DEVICE_TYPE_PCI) {
> > @@ -3438,12 +3440,21 @@ static int vfio_pci_hot_reset(VFIOPCIDevice *vdev, bool 
> > single)
> >                       ret = -EINVAL;
> >                       goto out_single;
> >                   }
> > +                found = true;
> >                   vfio_pci_pre_reset(tmp);
> >                   tmp->vbasedev.needs_reset = false;
> >                   multi = true;
> >                   break;
> >               }
> >           }
> > +
> > +        /*
> > +         * If we own the group but does not own the device, we also
> > +         * should call hot reset with multi.
> > +         */
> > +        if (!single && !found) {
> > +            multi = true;
> > +        }
> >       }
> >   
> >       if (!single && !multi) {