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Message-Id: <20240806023941.93454-2-baolu.lu@linux.intel.com>
Date: Tue, 6 Aug 2024 10:39:35 +0800
From: Lu Baolu <baolu.lu@...ux.intel.com>
To: Joerg Roedel <joro@...tes.org>,
Will Deacon <will@...nel.org>,
Robin Murphy <robin.murphy@....com>,
Jason Gunthorpe <jgg@...pe.ca>,
Kevin Tian <kevin.tian@...el.com>
Cc: iommu@...ts.linux.dev,
linux-kernel@...r.kernel.org,
Lu Baolu <baolu.lu@...ux.intel.com>
Subject: [PATCH v3 1/7] iommu/vt-d: Require DMA domain if hardware not support passthrough
The iommu core defines the def_domain_type callback to query the iommu
driver about hardware capability and quirks. The iommu driver should
declare IOMMU_DOMAIN_DMA requirement for hardware lacking pass-through
capability.
Earlier VT-d hardware implementations did not support pass-through
translation mode. The iommu driver relied on a paging domain with all
physical system memory addresses identically mapped to the same IOVA
to simulate pass-through translation before the def_domain_type was
introduced and it has been kept until now. It's time to adjust it now
to make the Intel iommu driver follow the def_domain_type semantics.
Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
---
drivers/iommu/intel/iommu.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 9ff8b83c19a3..90ad794a1be7 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2149,6 +2149,16 @@ static bool device_rmrr_is_relaxable(struct device *dev)
static int device_def_domain_type(struct device *dev)
{
+ struct device_domain_info *info = dev_iommu_priv_get(dev);
+ struct intel_iommu *iommu = info->iommu;
+
+ /*
+ * Hardware does not support the passthrough translation mode.
+ * Always use a dynamaic mapping domain.
+ */
+ if (!ecap_pass_through(iommu->ecap))
+ return IOMMU_DOMAIN_DMA;
+
if (dev_is_pci(dev)) {
struct pci_dev *pdev = to_pci_dev(dev);
--
2.34.1
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