linux-kernel - [PATCH 2/2] iommu/amd: Do not use IOMMUv2 functionality when SME is active

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Message-Id: <20200824105415.21000-3-joro@8bytes.org>
Date:   Mon, 24 Aug 2020 12:54:15 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     iommu@...ts.linux-foundation.org
Cc:     Joerg Roedel <joro@...tes.org>, jroedel@...e.de,
        Tom Lendacky <thomas.lendacky@....com>,
        Suravee Suthikulpanit <suravee.suthikulpanit@....com>,
        Alexander.Deucher@....com, linux-kernel@...r.kernel.org
Subject: [PATCH 2/2] iommu/amd: Do not use IOMMUv2 functionality when SME is active

From: Joerg Roedel <jroedel@...e.de>

When memory encryption is active the device is likely not in a direct
mapped domain. Forbid using IOMMUv2 functionality for now until finer
grained checks for this have been implemented.

Signed-off-by: Joerg Roedel <jroedel@...e.de>
---
 drivers/iommu/amd/iommu_v2.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/iommu/amd/iommu_v2.c b/drivers/iommu/amd/iommu_v2.c
index c259108ab6dd..0d175aed1d92 100644
--- a/drivers/iommu/amd/iommu_v2.c
+++ b/drivers/iommu/amd/iommu_v2.c
@@ -737,6 +737,13 @@ int amd_iommu_init_device(struct pci_dev *pdev, int pasids)
 
 	might_sleep();
 
+	/*
+	 * When memory encryption is active the device is likely not in a
+	 * direct-mapped domain. Forbid using IOMMUv2 functionality for now.
+	 */
+	if (mem_encrypt_active())
+		return -ENODEV;
+
 	if (!amd_iommu_v2_supported())
 		return -ENODEV;
 
-- 
2.28.0