linux-kernel - [PATCH 4/5] iommu/vt-d: Disallow SVA if devices don't support 64-bit address

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Date:   Tue, 20 Jul 2021 09:38:55 +0800
From:   Lu Baolu <baolu.lu@...ux.intel.com>
To:     Joerg Roedel <joro@...tes.org>,
        Sanjay Kumar <sanjay.k.kumar@...el.com>,
        Kevin Tian <kevin.tian@...el.com>,
        Ashok Raj <ashok.raj@...el.com>,
        Jacob Pan <jacob.jun.pan@...ux.intel.com>,
        Dave Jiang <dave.jiang@...el.com>,
        Liu Yi L <yi.l.liu@...el.com>
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH 4/5] iommu/vt-d: Disallow SVA if devices don't support 64-bit address

When the device and CPU share an address space (such as SVA), the device
must support the same addressing capability as the CPU. The CPU does not
consider the addressing ability of any device when managing the page table
of a process, so the device must have enough addressing ability to bind
the page table of the process.

Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
 drivers/iommu/intel/iommu.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index f45c80ce2381..f3cca1dd384d 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5372,6 +5372,9 @@ static int intel_iommu_enable_sva(struct device *dev)
 	if (!(iommu->flags & VTD_FLAG_SVM_CAPABLE))
 		return -ENODEV;
 
+	if (!dev->dma_mask || *dev->dma_mask != DMA_BIT_MASK(64))
+		return -ENODEV;
+
 	if (intel_iommu_enable_pasid(iommu, dev))
 		return -ENODEV;
 
-- 
2.25.1