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Subject[PATCH v2 4/4] iommu/vt-d: Calculate and set flags for handle_mm_fault
Date
Page requests are originated from the user page fault. Therefore, we
shall set FAULT_FLAG_USER. 

FAULT_FLAG_REMOTE indicates that we are walking an mm which is not
guaranteed to be the same as the current->mm and should not be subject
to protection key enforcement. Therefore, we should set FAULT_FLAG_REMOTE
to avoid faults when both SVM and PKEY are used.

References: commit 1b2ee1266ea6 ("mm/core: Do not enforce PKEY permissions on remote mm access")
Reviewed-by: Raj Ashok <ashok.raj@intel.com>
Acked-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
---
drivers/iommu/intel/svm.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index ff7ae7cc17d5..7bfd20a24a60 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -1086,6 +1086,7 @@ static irqreturn_t prq_event_thread(int irq, void *d)
struct intel_iommu *iommu = d;
struct intel_svm *svm = NULL;
int head, tail, handled = 0;
+ unsigned int flags = 0;

/* Clear PPR bit before reading head/tail registers, to
* ensure that we get a new interrupt if needed. */
@@ -1186,9 +1187,11 @@ static irqreturn_t prq_event_thread(int irq, void *d)
if (access_error(vma, req))
goto invalid;

- ret = handle_mm_fault(vma, address,
- req->wr_req ? FAULT_FLAG_WRITE : 0,
- NULL);
+ flags = FAULT_FLAG_USER | FAULT_FLAG_REMOTE;
+ if (req->wr_req)
+ flags |= FAULT_FLAG_WRITE;
+
+ ret = handle_mm_fault(vma, address, flags, NULL);
if (ret & VM_FAULT_ERROR)
goto invalid;

--
2.25.1
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