[PATCH 3/4] iommu/vt-d: Add a check for 5-level paging support

[Sohil Mehta]

Add a check to verify IOMMU 5-level paging support. If the CPU supports
supports 5-level paging but the IOMMU does not support it then disable
SVM by not allocating PASID tables.

Signed-off-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
---
 drivers/iommu/intel-svm.c   | 4 ++++
 include/linux/intel-iommu.h | 1 +
 2 files changed, 5 insertions(+)

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index fcab440..4072a18 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -45,6 +45,10 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
 			!cap_fl1gp_support(iommu->cap))
 		return -EINVAL;
 
+	if (cpu_feature_enabled(X86_FEATURE_LA57) &&
+			!cap_5lp_support(iommu->cap))
+		return -EINVAL;
+
 	/* Start at 2 because it's defined as 2^(1+PSS) */
 	iommu->pasid_max = 2 << ecap_pss(iommu->ecap);
 
diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
index a56bab1..8dad3dd 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -83,6 +83,7 @@
 /*
  * Decoding Capability Register
  */
+#define cap_5lp_support(c)	(((c) >> 60) & 1)
 #define cap_pi_support(c)	(((c) >> 59) & 1)
 #define cap_fl1gp_support(c)	(((c) >> 56) & 1)
 #define cap_read_drain(c)	(((c) >> 55) & 1)
-- 
2.7.4