lkml.org 
[lkml]   [2018]   [Mar]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/1] iommu/vt-d: Use real PASID for flush in caching mode
Date
If caching mode is supported, the hardware will cache
none-present or erroneous translation entries. Hence,
software should explicitly invalidate the PASID cache
after a PASID table entry becomes present. We should
issue such invalidation with the PASID value that we
have changed. PASID 0 is not reserved for this case.

Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Kevin Tian <kevin.tian@intel.com>
Cc: Sankaran Rajesh <rajesh.sankaran@intel.com>
Suggested-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
drivers/iommu/intel-svm.c | 16 ++++++----------
1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 99bc9bd..b7b88b5 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -422,17 +422,13 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
iommu->pasid_table[svm->pasid].val = pasid_entry_val;

wmb();
- /* In caching mode, we still have to flush with PASID 0 when
- * a PASID table entry becomes present. Not entirely clear
- * *why* that would be the case — surely we could just issue
- * a flush with the PASID value that we've changed? The PASID
- * is the index into the table, after all. It's not like domain
- * IDs in the case of the equivalent context-entry change in
- * caching mode. And for that matter it's not entirely clear why
- * a VMM would be in the business of caching the PASID table
- * anyway. Surely that can be left entirely to the guest? */
+
+ /*
+ * Flush PASID cache when a PASID table entry becomes
+ * present.
+ */
if (cap_caching_mode(iommu->cap))
- intel_flush_pasid_dev(svm, sdev, 0);
+ intel_flush_pasid_dev(svm, sdev, svm->pasid);
}
list_add_rcu(&sdev->list, &svm->devs);

--
2.7.4
\
 
 \ /
  Last update: 2018-03-16 05:39    [W:0.032 / U:3.520 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site