Re: [SeaBIOS] [Qemu-devel] [PATCH] boot: fix path pattern of scsi device

[Amos Kong]

On Tue, May 28, 2013 at 10:06:51AM +0200, Paolo Bonzini wrote:
> Il 28/05/2013 09:40, Amos Kong ha scritto:
> > bootindex parameter of scsi device doesn't work, it causes
> > by wrong pattern in seabios.
> >
> > qemu passes the following firmware dev_path to seabios:
> >  /pci@i0cf8/scsi@4/virtio-scsi-device/channel@0/disk@0,0
>
> No, this is another unexpected change due to the virtio refactoring in
> QEMU.  The right fix is in QEMU, by adding a get_fw_dev_path
> implementation in hw/virtio/virtio-bus.c.

Hi Paolo,

We could not fix this by implementing get_fw_dev_path in
hw/virtio/virtio-bus.c

virtio-bus is the parent bus of scsi-bus, scsibus_get_fw_dev_path()
will be called after called virtio_bus_get_fw_dev_path().

str0 = returns of parents of virtio-bus  /* eg: /pci@i0cf8/scsi@4  */
str1 = return of virtio_bus_get_fw_dev_path() /* eg: .. */
str2 = scsibus_get_fw_dev_path() /* eg: channel@0/disk@0,0 */

The final fw_dev_path should be $str0/$str1/$str2

| static int qdev_get_fw_dev_path_helper(DeviceState *dev, char *p, int size)
| {
|     int l = 0;
| 
|     if (dev && dev->parent_bus) {
|         char *d;
|         l = qdev_get_fw_dev_path_helper(dev->parent_bus->parent, p, size);
|         d = bus_get_fw_dev_path(dev->parent_bus, dev);
|         if (d) {
|             l += snprintf(p + l, size - l, "%s", d);
|             g_free(d);

if we implement virtio_bus_get_fw_dev_path(), the return value will be set to $str1

|         } else {
|             l += snprintf(p + l, size - l, "%s", object_get_typename(OBJECT(dev)));

Currently we didn't implement virtio_bus_get_fw_dev_path(), so 'virtio-scsi-device' was set to $str1

|         }
|

However, we need to change the pattern.

Amos.
> We fixed it already for migration paths, it should be easy to do the
> same for this.
>
> Please Cc [e-mail] when sending the QEMU patch.
>
> Thanks,
>
> Paolo
> > Signed-off-by: Amos Kong
> >
> > src/boot.c | 5 +++--
> >  1 file changed, 3 insertions(+), 2 deletions(-)
> >
> > diff --git a/src/boot.c b/src/boot.c
> > index c308602..cd9d784 100644
> > --- a/src/boot.c
> > +++ b/src/boot.c
> > @@ -138,10 +138,11 @@ int bootprio_find_scsi_device(struct pci_device *pci, int target, int lun)
> >      if (!pci)
> >          // support only pci machine for now
> >          return -1;
> > // Find scsi drive - for example: /pci@i0cf8/scsi@5/channel@0/disk@1,0
> > /* Find scsi drive - for example:
> >   /pci@i0cf8/scsi@5/virtio-scsi-device/channel@0/disk@1,0 */
> > char desc[256], *p;
> >    p = build_pci_path(desc, sizeof(desc), "*", pci);
> > snprintf(p, desc+sizeof(desc)-p, "/*@0/*@%d,%d", target, lun);
> > snprintf(p, desc+sizeof(desc)-p, "/*/*@0/*@%d,%d", target, lun);
> > return find_prio(desc);
> >
> > }