Different encodings are used to represent supported PASID bits
and number of PASID table entries.
The current code assigns ecap_pss directly to extended context
table entry PTS which is wrong and could result in writing
non-zero bits to the reserved fields. IOMMU fault reason
11 will be reported when reserved bits are nonzero.
This patch converts ecap_pss to extend context entry pts encoding
based on VT-d spec. Chapter 9.4 as follows:
- number of PASID bits = ecap_pss + 1
- number of PASID table entries = 2^(pts + 5)
Software assigned limit of pasid_max value is also respected to
match the allocation limitation of PASID table.
cc: Mika Kuoppala <mika.kuopp...@linux.intel.com>
cc: Ashok Raj <ashok....@intel.com>
Signed-off-by: Jacob Pan <jacob.jun....@linux.intel.com>
---
drivers/iommu/intel-iommu.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 27596e6..5d9cddc 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5173,6 +5173,25 @@ static void intel_iommu_remove_device(struct device *dev)
}
#ifdef CONFIG_INTEL_IOMMU_SVM
+#define MAX_NR_PASID_BITS (20)
+static inline unsigned long intel_iommu_get_pts(struct intel_iommu *iommu)
+{
+ /*
+ * Convert ecap_pss to extend context entry pts encoding, also
+ * respect the soft pasid_max value set by the iommu.
+ * - number of PASID bits = ecap_pss + 1
+ * - number of PASID table entries = 2^(pts + 5)
+ * Therefore, pts = ecap_pss - 4
+ * e.g. KBL ecap_pss = 0x13, PASID has 20 bits, pts = 15
+ */
+ if (ecap_pss(iommu->ecap) < 5)
+ return 0;
+
+ /* pasid_max is encoded as actual number of entries not the bits */
+ return find_first_bit((unsigned long *)&iommu->pasid_max,
+ MAX_NR_PASID_BITS) - 5;
+}
+
int intel_iommu_enable_pasid(struct intel_iommu *iommu, struct intel_svm_dev
*sdev)
{
struct device_domain_info *info;
@@ -5205,7 +5224,9 @@ int intel_iommu_enable_pasid(struct intel_iommu *iommu,
struct intel_svm_dev *sd
if (!(ctx_lo & CONTEXT_PASIDE)) {
context[1].hi = (u64)virt_to_phys(iommu->pasid_state_table);
- context[1].lo = (u64)virt_to_phys(iommu->pasid_table) |
ecap_pss(iommu->ecap);
+ context[1].lo = (u64)virt_to_phys(iommu->pasid_table) |
+ intel_iommu_get_pts(iommu);
+
wmb();
/* CONTEXT_TT_MULTI_LEVEL and CONTEXT_TT_DEV_IOTLB are both
* extended to permit requests-with-PASID if the PASIDE bit
--
2.7.4
