Re: [Qemu-devel] [PATCH v2 2/2] pci: allow DeviceClass fw_name to override pci_dev_fw_name() if set

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

On Fri, Jun 29, 2018 at 02:56:16PM +0100, Mark Cave-Ayland wrote:
> The current implementation of pci_dev_fw_name() scans through a fixed
> set of PCI class descriptions to determine the firmware device name
> but in some cases this isn't always appropriate, for example with
> the macio device which uses a class code of 0xff (unassigned).
> 
> Rather than add a new entry for the macio device and risk a potential
> clash with another unassigned device later, add a check to
> pcibus_get_fw_dev_path() that will use DeviceClass fw_name if set in
> preference to pci_dev_fw_name().
> 
> This enables PCI devices such as macio to set dc->fw_name as required
> to match the name specified in the firmware.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  hw/pci/pci.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/pci/pci.c b/hw/pci/pci.c
> index 80bc45930d..126dd683dc 100644
> --- a/hw/pci/pci.c
> +++ b/hw/pci/pci.c
> @@ -2411,12 +2411,14 @@ static char *pci_dev_fw_name(DeviceState *dev, char *buf, int len)
>  
>  static char *pcibus_get_fw_dev_path(DeviceState *dev)
>  {
> +    DeviceClass *dc = DEVICE_GET_CLASS(dev);
>      PCIDevice *d = (PCIDevice *)dev;
>      char path[50], name[33];
>      int off;
>  
>      off = snprintf(path, sizeof(path), "%s@%x",
> -                   pci_dev_fw_name(dev, name, sizeof name),
> +                   dc->fw_name ? dc->fw_name :
> +                       pci_dev_fw_name(dev, name, sizeof name),
>                     PCI_SLOT(d->devfn));

So why not put the logic into pci_dev_fw_name then?



>      if (PCI_FUNC(d->devfn))
>          snprintf(path + off, sizeof(path) + off, ",%x", PCI_FUNC(d->devfn));
> -- 
> 2.11.0