Messages in this thread | | | Date | Mon, 29 Jun 2020 21:57:03 -0700 | From | Jacob Pan <> | Subject | Re: [PATCH 3/7] iommu/vt-d: Fix PASID devTLB invalidation |
| |
On Thu, 25 Jun 2020 15:25:57 +0800 Lu Baolu <baolu.lu@linux.intel.com> wrote:
> On 2020/6/23 23:43, 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.pan@linux.intel.com> > > --- > > 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..3991a24539a1 > > 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) > > How about > > 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); > > ? > > It makes the code more readable and still works even we reassign > another pasid for RID2PASID. > agreed, thanks.
> Best regards, > baolu > > > + qi_flush_dev_iotlb_pasid(iommu, sid, pfsid, pasid, > > qdep, 0, 64 - VTD_PAGE_SHIFT); > > + else > > + qi_flush_dev_iotlb(iommu, sid, pfsid, qdep, 0, 64 > > - VTD_PAGE_SHIFT); } > > > > void intel_pasid_tear_down_entry(struct intel_iommu *iommu, > > struct device *dev,
[Jacob Pan]
| |