Hi Jacob, On 7/1/20 5:33 PM, Jacob Pan wrote: > DevTLB flush can be used for both DMA request with and without PASIDs. > The former uses PASID#0 (RID2PASID), latter uses non-zero PASID for SVA > usage. > > This patch adds a check for PASID value such that devTLB flush with > PASID is used for SVA case. This is more efficient in that multiple > PASIDs can be used by a single device, when tearing down a PASID entry > we shall flush only the devTLB specific to a PASID. > > Fixes: 6f7db75e1c46 ("iommu/vt-d: Add second level page table") > Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com> Reviewed-by: Eric Auger <eric.au...@redhat.com>
Thanks Eric > --- > drivers/iommu/intel/pasid.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c > index c81f0f17c6ba..fa0154cce537 100644 > --- a/drivers/iommu/intel/pasid.c > +++ b/drivers/iommu/intel/pasid.c > @@ -486,7 +486,16 @@ devtlb_invalidation_with_pasid(struct intel_iommu *iommu, > qdep = info->ats_qdep; > pfsid = info->pfsid; > > - qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 - VTD_PAGE_SHIFT); > + /* > + * When PASID 0 is used, it indicates RID2PASID(DMA request w/o PASID), > + * devTLB flush w/o PASID should be used. For non-zero PASID under > + * SVA usage, device could do DMA with multiple PASIDs. It is more > + * efficient to flush devTLB specific to the PASID. > + */ > + if (pasid == PASID_RID2PASID) > + qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 - > VTD_PAGE_SHIFT); > + else > + qi_flush_dev_iotlb_pasid(iommu, sid, pfsid, pasid, qdep, 0, 64 > - VTD_PAGE_SHIFT); > } > > void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct device > *dev, > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu