RE: [PATCH v5 13/15] vfio/pci: Expose PCIe PASID capability to guest

[Liu, Yi L]

Hi Eric,

> From: Auger Eric <eric.auger@xxxxxxxxxx>
> Sent: Monday, July 20, 2020 8:35 PM
> 
> Yi,
> 
> On 7/12/20 1:21 PM, Liu Yi L wrote:
> > This patch exposes PCIe PASID capability to guest for assigned devices.
> > Existing vfio_pci driver hides it from guest by setting the capability
> > length as 0 in pci_ext_cap_length[].
> >
> > And this patch only exposes PASID capability for devices which has PCIe
> > PASID extended struture in its configuration space. So VFs, will will
> s/will//

got it.

> > not see PASID capability on VFs as VF doesn't implement PASID extended
> suggested rewording: VFs will not expose the PASID capability as they do
> not implement the PASID extended structure in their config space?

make sense. will modify it.

> > structure in its configuration space. For VF, it is a TODO in future.
> > Related discussion can be found in below link:
> >
> > https://lkml.org/lkml/2020/4/7/693
> 
> >
> > Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> > CC: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> > Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
> > Cc: Eric Auger <eric.auger@xxxxxxxxxx>
> > Cc: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> > Cc: Joerg Roedel <joro@xxxxxxxxxx>
> > Cc: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> > Signed-off-by: Liu Yi L <yi.l.liu@xxxxxxxxx>
> > ---
> > v1 -> v2:
> > *) added in v2, but it was sent in a separate patchseries before
> > ---
> >  drivers/vfio/pci/vfio_pci_config.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/vfio/pci/vfio_pci_config.c b/drivers/vfio/pci/vfio_pci_config.c
> > index d98843f..07ff2e6 100644
> > --- a/drivers/vfio/pci/vfio_pci_config.c
> > +++ b/drivers/vfio/pci/vfio_pci_config.c
> > @@ -95,7 +95,7 @@ static const u16 pci_ext_cap_length[PCI_EXT_CAP_ID_MAX +
> 1] = {
> >  	[PCI_EXT_CAP_ID_LTR]	=	PCI_EXT_CAP_LTR_SIZEOF,
> >  	[PCI_EXT_CAP_ID_SECPCI]	=	0,	/* not yet */
> >  	[PCI_EXT_CAP_ID_PMUX]	=	0,	/* not yet */
> > -	[PCI_EXT_CAP_ID_PASID]	=	0,	/* not yet */
> > +	[PCI_EXT_CAP_ID_PASID]	=	PCI_EXT_CAP_PASID_SIZEOF,
> >  };
> >
> >  /*
> >
> Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>

thanks.

Regards,
Yi Liu

> Thanks
> 
> Eric