iommu/vt-d: Add a check for 1GB page support

Add a check to verify IOMMU 1GB page support. If the CPU supports 1GB
pages but the IOMMU does not support it then disable SVM by not
allocating PASID tables.

Signed-off-by: Sohil Mehta <sohil.mehta@intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

2 files changed, 5 insertions, 0 deletions

diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
index 6643277e321e..e9a56ad09a76 100644
--- a/drivers/iommu/intel-svm.c
+++ b/drivers/iommu/intel-svm.c
@@ -41,6 +41,10 @@ int intel_svm_alloc_pasid_tables(struct intel_iommu *iommu)
         struct page *pages;
         int order;
 
+        if (cpu_feature_enabled(X86_FEATURE_GBPAGES) &&
+                        !cap_fl1gp_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 f3274d9f46a2..a56bab114f39 100644
--- a/include/linux/intel-iommu.h
+++ b/include/linux/intel-iommu.h
@@ -84,6 +84,7 @@
  * Decoding Capability Register
  */
 #define cap_pi_support(c)       (((c) >> 59) & 1)
+#define cap_fl1gp_support(c)    (((c) >> 56) & 1)
 #define cap_read_drain(c)       (((c) >> 55) & 1)
 #define cap_write_drain(c)      (((c) >> 54) & 1)
 #define cap_max_amask_val(c)    (((c) >> 48) & 0x3f)