On Thu, 10 Sep 2020 03:45:30 -0700 Liu Yi L <yi.l.liu@xxxxxxxxx> 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[]. This exposes the PASID capability, but it's still read-only, so this largely just helps userspace know where to emulate the capability, right? Thanks, Alex > And this patch only exposes PASID capability for devices which has PCIe > PASID extended struture in its configuration space. VFs will not expose > the PASID capability as they do not implement the PASID extended structure > in their config space. It is a TODO in future. Related discussion can be > found in below link: > > https://lore.kernel.org/kvm/20200407095801.648b1371@xxxxxxxxx/ > > 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> > Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx> > --- > v5 -> v6: > *) add review-by from Eric Auger. > > 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, > }; > > /*
