linux-kernel - [PATCH v5 4/7] iommu/vt-d: Handle non-page aligned address

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Date:   Wed, 22 Jul 2020 12:26:24 -0700
From:   Jacob Pan <jacob.jun.pan@...ux.intel.com>
To:     iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>,
        "Lu Baolu" <baolu.lu@...ux.intel.com>,
        Joerg Roedel <joro@...tes.org>,
        David Woodhouse <dwmw2@...radead.org>
Cc:     Yi Liu <yi.l.liu@...el.com>, "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>,
        Eric Auger <eric.auger@...hat.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>
Subject: [PATCH v5 4/7] iommu/vt-d: Handle non-page aligned address

From: Liu Yi L <yi.l.liu@...el.com>

Address information for device TLB invalidation comes from userspace
when device is directly assigned to a guest with vIOMMU support.
VT-d requires page aligned address. This patch checks and enforce
address to be page aligned, otherwise reserved bits can be set in the
invalidation descriptor. Unrecoverable fault will be reported due to
non-zero value in the reserved bits.

Fixes: 61a06a16e36d8 ("iommu/vt-d: Support flushing more translation
cache types")
Acked-by: Lu Baolu <baolu.lu@...ux.intel.com>
Signed-off-by: Liu Yi L <yi.l.liu@...el.com>
Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Reviewed-by: Eric Auger <eric.auger@...hat.com>
---
 drivers/iommu/intel/dmar.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c
index 9be08b9400ee..6038d02c5066 100644
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1456,9 +1456,25 @@ void qi_flush_dev_iotlb_pasid(struct intel_iommu *iommu, u16 sid, u16 pfsid,
 	 * Max Invs Pending (MIP) is set to 0 for now until we have DIT in
 	 * ECAP.
 	 */
-	desc.qw1 |= addr & ~mask;
-	if (size_order)
+	if (addr & GENMASK_ULL(size_order + VTD_PAGE_SHIFT, 0))
+		pr_warn_ratelimited("Invalidate non-aligned address %llx, order %d\n", addr, size_order);
+
+	/* Take page address */
+	desc.qw1 = QI_DEV_EIOTLB_ADDR(addr);
+
+	if (size_order) {
+		/*
+		 * Existing 0s in address below size_order may be the least
+		 * significant bit, we must set them to 1s to avoid having
+		 * smaller size than desired.
+		 */
+		desc.qw1 |= GENMASK_ULL(size_order + VTD_PAGE_SHIFT - 1,
+					VTD_PAGE_SHIFT);
+		/* Clear size_order bit to indicate size */
+		desc.qw1 &= ~mask;
+		/* Set the S bit to indicate flushing more than 1 page */
 		desc.qw1 |= QI_DEV_EIOTLB_SIZE;
+	}
 
 	qi_submit_sync(iommu, &desc, 1, 0);
 }
-- 
2.7.4