Re: [Xen-devel] [PATCH] pci: treat class 0 devices as endpoints

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 08/05/18 10:33, Roger Pau Monne wrote:
> Class 0 devices are legacy pre PCI 2.0 devices that didn't have a
> class code. Treat them as endpoints, so that they can be handled by
> the IOMMU and properly passed-through to the hardware domain.
>
> Such device has been seen on a Super Micro server, lspci -vv reports:
>
> 00:13.0 Non-VGA unclassified device: Intel Corporation Device a135 (rev 31)
>       Subsystem: Super Micro Computer Inc Device 0931
>       Flags: bus master, fast devsel, latency 0, IRQ 11
>       Memory at df222000 (64-bit, non-prefetchable) [size=4K]
>       Capabilities: [80] Power Management version 3
>
> Arguably this is not a legacy device (since this is a new server), but
> in any case Xen needs to deal with it.
>
> Suggested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>

FWIW, An updated lspci reports:

00:13.0 Non-VGA unclassified device: Intel Corporation Sunrise Point-H 
Integrated Sensor Hub (rev 31)
        Subsystem: Super Micro Computer Inc Device 0931

~Andrew

> ---
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> ---
>  xen/drivers/passthrough/pci.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
> index 1db69d5b99..c4890a4295 100644
> --- a/xen/drivers/passthrough/pci.c
> +++ b/xen/drivers/passthrough/pci.c
> @@ -927,10 +927,11 @@ enum pdev_type pdev_type(u16 seg, u8 bus, u8 devfn)
>      case PCI_CLASS_BRIDGE_HOST:
>          return DEV_TYPE_PCI_HOST_BRIDGE;
>  
> -    case 0x0000: case 0xffff:
> +    case 0xffff:
>          return DEV_TYPE_PCI_UNKNOWN;
>      }
>  
> +    /* NB: treat legacy pre PCI 2.0 devices (class_device == 0) as 
> endpoints. */
>      return pos ? DEV_TYPE_PCIe_ENDPOINT : DEV_TYPE_PCI;
>  }
>  


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