release/5.2.40/iommu-vt-d-Match-CPU-and-IOMMU-paging-mode.patch

From a2fb3fd4b28ce8f72cdc87510cf238840b0e02d9 Mon Sep 17 00:00:00 2001
From: Jacob Pan <jacob.jun.pan@linux.intel.com>
Date: Thu, 2 Jan 2020 08:18:04 +0800
Subject: [PATCH] iommu/vt-d: Match CPU and IOMMU paging mode

commit 79db7e1b4cf2a006f556099c13de3b12970fc6e3 upstream.

When setting up first level page tables for sharing with CPU, we need
to ensure IOMMU can support no less than the levels supported by the
CPU.

It is not adequate, as in the current code, to set up 5-level paging
in PASID entry First Level Paging Mode(FLPM) solely based on CPU.

Currently, intel_pasid_setup_first_level() is only used by native SVM
code which already checks paging mode matches. However, future use of
this helper function may not be limited to native SVM.
https://lkml.org/lkml/2019/11/18/1037

Fixes: 437f35e1cd4c8 ("iommu/vt-d: Add first level page table interface")
Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
index fe51d8af457f..9328471d0d01 100644
--- a/drivers/iommu/intel-pasid.c
+++ b/drivers/iommu/intel-pasid.c
@@ -516,8 +516,16 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 	}
 
 #ifdef CONFIG_X86
-	if (cpu_feature_enabled(X86_FEATURE_LA57))
-		pasid_set_flpm(pte, 1);
+	/* Both CPU and IOMMU paging mode need to match */
+	if (cpu_feature_enabled(X86_FEATURE_LA57)) {
+		if (cap_5lp_support(iommu->cap)) {
+			pasid_set_flpm(pte, 1);
+		} else {
+			pr_err("VT-d has no 5-level paging support for CPU\n");
+			pasid_clear_entry(pte);
+			return -EINVAL;
+		}
+	}
 #endif /* CONFIG_X86 */
 
 	pasid_set_domain_id(pte, did);
-- 
2.7.4