Hi Baolu,
On Thu, Mar 12, 2020 at 09:44:16AM +0800, Lu Baolu wrote:
> Hi Jean,
>
> On 2020/3/11 20:45, Jean-Philippe Brucker wrote:
> > The pci_ats_supported() function checks if a device supports ATS and is
> > allowed to use it.
> >
> > Signed-off-by: Jean-Philippe Brucker <jean-philippe@xxxxxxxxxx>
> > ---
> > drivers/iommu/intel-iommu.c | 9 +++------
> > 1 file changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> > index 6fa6de2b6ad5..17208280ef5c 100644
> > --- a/drivers/iommu/intel-iommu.c
> > +++ b/drivers/iommu/intel-iommu.c
> > @@ -1454,8 +1454,7 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info)
> > !pci_reset_pri(pdev) && !pci_enable_pri(pdev, 32))
> > info->pri_enabled = 1;
> > #endif
> > - if (!pdev->untrusted && info->ats_supported &&
> > - pci_ats_page_aligned(pdev) &&
> > + if (info->ats_supported && pci_ats_page_aligned(pdev) &&
> > !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {
> > info->ats_enabled = 1;
> > domain_update_iotlb(info->domain);
> > @@ -2611,10 +2610,8 @@ static struct dmar_domain *dmar_insert_one_dev_info(struct intel_iommu *iommu,
> > if (dev && dev_is_pci(dev)) {
> > struct pci_dev *pdev = to_pci_dev(info->dev);
> > - if (!pdev->untrusted &&
> > - !pci_ats_disabled() &&
>
> The pci_ats_disabled() couldn't be replaced by pci_ats_supported(). Even
> pci_ats_supported() returns true, user still can disable it. Or move
> ats_disabled into pci_ats_supported()?
It is already there, but hidden behind the "if (!dev->ats_cap)":
pci_ats_init() only sets dev->ats_cap after checking that
pci_ats_disabled() returns false.
Thanks,
Jean
>
> Best regards,
> baolu
>
> > - ecap_dev_iotlb_support(iommu->ecap) &&
> > - pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS) &&
> > + if (ecap_dev_iotlb_support(iommu->ecap) &&
> > + pci_ats_supported(pdev) &&
> > dmar_find_matched_atsr_unit(pdev))
> > info->ats_supported = 1;
