Re: [Qemu-devel] [PATCH] pci: fixes to allow booting from extra root pci buses.

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Jun 11, 2015 at 03:41:35PM +0300, Marcel Apfelbaum wrote:
> The PXB device exposes a new pci root bridge with the
> fw path:  /pci-root@4/..., in which 4 is the root bus number.
> Before this patch the fw path was wrongly computed:
>     /pci-root@1/pci@i0cf8/...
> Fix the above issues: Correct the bus number and remove the
> extra host bridge description.
> 
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>

I would like a unit test for various paths, they
are part of guest ABI so we can never change them.
Could you add a unit test please?

Also can you please quote the open firmware spec text
that says this is the correct format?

> ---
> Laszlo worked on supporting pxb for OVMF and discovered
> that there is a problem when booting devices from a PXB.
> 
> This is a link to the latest QEMU series:
>     https://www.mail-archive.com/qemu-devel@nongnu.org/msg302493.html
> 
> Thanks,
> Marcel
> 
>  src/boot.c   | 1 -
>  src/hw/pci.c | 2 +-
>  2 files changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/src/boot.c b/src/boot.c
> index ec59c37..a3bb13b 100644
> --- a/src/boot.c
> +++ b/src/boot.c
> @@ -114,7 +114,6 @@ build_pci_path(char *buf, int max, const char *devname, struct pci_device *pci)
>      } else {
>          if (pci->rootbus)
>              p += snprintf(p, max, "/pci-root@%x", pci->rootbus);
> -        p += snprintf(p, buf+max-p, "%s", FW_PCI_DOMAIN);
>      }
>  
>      int dev = pci_bdf_to_dev(pci->bdf), fn = pci_bdf_to_fn(pci->bdf);
> diff --git a/src/hw/pci.c b/src/hw/pci.c
> index 0379b55..9e77af4 100644
> --- a/src/hw/pci.c
> +++ b/src/hw/pci.c
> @@ -133,7 +133,7 @@ pci_probe_devices(void)
>                  if (bus != lastbus)
>                      rootbuses++;
>                  lastbus = bus;
> -                rootbus = rootbuses;
> +                rootbus = bus;
>                  if (bus > MaxPCIBus)
>                      MaxPCIBus = bus;
>              } else {
> -- 
> 2.1.0