Re: [Qemu-devel] [PULL v3 14/15] virtio-pci: fix migration for pci bus master

[Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>]

Hi Alex/Peter,

The below patch is already been picked in master and ppc-next and has
broken pseries booting from virtio-blk device

Greg Kurz <gkurz@linux.vnet.ibm.com> writes:
> On Tue, 23 Sep 2014 07:26:32 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
>
>> > 
>> > This commit prevents pseries to boot. SLOF complains with the following messages:
>> > 
>> > Trying to load:  from: /pci@800000020000000/scsi@0 ... virtioblk_read failed! status = 255
>> > virtioblk_read failed! status = 255
>> > virtioblk_read failed! status = 255
>> > ...
>> > 
>> > I'll try to debug some more.
>> > 

>> > > @@ -480,13 +469,18 @@ static void virtio_write_config(PCIDevice *pci_dev, uint32_t address,
>> > >      VirtIOPCIProxy *proxy = DO_UPCAST(VirtIOPCIProxy, pci_dev, pci_dev);
>> > >      VirtIODevice *vdev = virtio_bus_get_device(&proxy->bus);
>> > > 
>> > > +    uint8_t cmd = proxy->pci_dev.config[PCI_COMMAND];
>> > > +
>> > >      pci_default_write_config(pci_dev, address, val, len);
>> > > 
>> > >      if (range_covers_byte(address, len, PCI_COMMAND) &&
>> > >          !(pci_dev->config[PCI_COMMAND] & PCI_COMMAND_MASTER) &&
>> > > -        !(proxy->flags & VIRTIO_PCI_FLAG_BUS_MASTER_BUG)) {
>> > > +        (cmd & PCI_COMMAND_MASTER)) {
>> > > +        /* Bus driver disables bus mastering - make it act
>> > > +         * as a kind of reset to render the device quiescent. */
>> > >          virtio_pci_stop_ioeventfd(proxy);
>> > > -        virtio_set_status(vdev, vdev->status & ~VIRTIO_CONFIG_S_DRIVER_OK);
>> > > +        virtio_reset(vdev);
>> > > +        msix_unuse_all_vectors(&proxy->pci_dev);
>> > >      }
>> > >  }
>> > > 
>> 

Regards
Nikunj