On Fri, Jun 18, 2021 at 02:55:14PM -0600, Alex Williamson wrote: > PCIe Address Translation Services (ATS) provides a mechanism for a > device to provide an on-device caching translation agent (device > iotlb). We already have a means to disable support for this feature > via the pci=noats option. For untrusted and externally facing > devices, we not only disable ATS support for the device, but we use > Access Control Services (ACS) Transaction Blocking to actively > prevent devices from sending TLPs with non-default AT field values. > > Extend pci=noats to also make use of PCI_ACS_TB so that not only is > ATS disabled at the device, but blocked at the downstream ports. > This provides a means to further lock-down ATS for cases such as > device assignment, where it may not be the hardware configuration of > the device that makes it untrusted, but the driver running on the > device. > > Cc: Rajat Jain <rajatja@xxxxxxxxxx> > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> Applied to pci/virtualization for v5.15, thanks! > --- > drivers/pci/pci.c | 4 ++-- > drivers/pci/quirks.c | 2 +- > 2 files changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index 68f57d86b243..5aa1bb2ddd80 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -915,8 +915,8 @@ static void pci_std_enable_acs(struct pci_dev *dev) > /* Upstream Forwarding */ > ctrl |= (cap & PCI_ACS_UF); > > - /* Enable Translation Blocking for external devices */ > - if (dev->external_facing || dev->untrusted) > + /* Enable Translation Blocking for external devices and noats */ > + if (pci_ats_disabled() || dev->external_facing || dev->untrusted) > ctrl |= (cap & PCI_ACS_TB); > > pci_write_config_word(dev, pos + PCI_ACS_CTRL, ctrl); > diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c > index 6d74386eadc2..d541076c083a 100644 > --- a/drivers/pci/quirks.c > +++ b/drivers/pci/quirks.c > @@ -5031,7 +5031,7 @@ static int pci_quirk_enable_intel_spt_pch_acs(struct pci_dev *dev) > ctrl |= (cap & PCI_ACS_CR); > ctrl |= (cap & PCI_ACS_UF); > > - if (dev->external_facing || dev->untrusted) > + if (pci_ats_disabled() || dev->external_facing || dev->untrusted) > ctrl |= (cap & PCI_ACS_TB); > > pci_write_config_dword(dev, pos + INTEL_SPT_ACS_CTRL, ctrl); > >
