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From: Lu Baolu <baolu.lu@linux.intel.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: ashok.raj@intel.com, jacob.jun.pan@linux.intel.com,
	kevin.tian@intel.com,
	Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>,
	iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	Daniel Drake <drake@endlessm.com>,
	Derrick Jonathan <jonathan.derrick@intel.com>,
	Jerry Snitselaar <jsnitsel@redhat.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Christoph Hellwig <hch@lst.de>,
	Lu Baolu <baolu.lu@linux.intel.com>
Subject: [PATCH v2 4/6] iommu/vt-d: Don't force PCI sub-hierarchy to use DMA domain
Date: Sat, 14 Mar 2020 09:07:03 +0800	[thread overview]
Message-ID: <20200314010705.30711-5-baolu.lu@linux.intel.com> (raw)
In-Reply-To: <20200314010705.30711-1-baolu.lu@linux.intel.com>

Before commit fa954e6831789 ("iommu/vt-d: Delegate the dma domain
to upper layer"), Intel IOMMU started off with all devices in the
identity domain, and took them out later if it found they couldn't
access all of memory. This required devices behind a PCI bridge to
use a DMA domain at the beginning because all PCI devices behind
the bridge use the same source-id in their transactions and the
domain couldn't be changed at run-time.

Intel IOMMU driver is now aligned with the default domain framework,
there's no need to keep this requirement anymore.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/intel-iommu.c | 25 -------------------------
 1 file changed, 25 deletions(-)

diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index eb68ba5ddf67..351a83f40527 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -3048,31 +3048,6 @@ static int device_def_domain_type(struct device *dev)
 
 		if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev))
 			return IOMMU_DOMAIN_IDENTITY;
-
-		/*
-		 * We want to start off with all devices in the 1:1 domain, and
-		 * take them out later if we find they can't access all of memory.
-		 *
-		 * However, we can't do this for PCI devices behind bridges,
-		 * because all PCI devices behind the same bridge will end up
-		 * with the same source-id on their transactions.
-		 *
-		 * Practically speaking, we can't change things around for these
-		 * devices at run-time, because we can't be sure there'll be no
-		 * DMA transactions in flight for any of their siblings.
-		 *
-		 * So PCI devices (unless they're on the root bus) as well as
-		 * their parent PCI-PCI or PCIe-PCI bridges must be left _out_ of
-		 * the 1:1 domain, just in _case_ one of their siblings turns out
-		 * not to be able to map all of memory.
-		 */
-		if (!pci_is_pcie(pdev)) {
-			if (!pci_is_root_bus(pdev->bus))
-				return IOMMU_DOMAIN_DMA;
-			if (pdev->class >> 8 == PCI_CLASS_BRIDGE_PCI)
-				return IOMMU_DOMAIN_DMA;
-		} else if (pci_pcie_type(pdev) == PCI_EXP_TYPE_PCI_BRIDGE)
-			return IOMMU_DOMAIN_DMA;
 	}
 
 	return 0;
-- 
2.17.1


  parent reply	other threads:[~2020-03-14  1:10 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-14  1:06 [PATCH v2 0/6] Replace private domain with per-group default domain Lu Baolu
2020-03-14  1:07 ` [PATCH v2 1/6] iommu: Add def_domain_type() callback in iommu_ops Lu Baolu
2020-03-14  1:07 ` [PATCH v2 2/6] iommu: Configure default domain with def_domain_type Lu Baolu
2020-03-19 14:03   ` Joerg Roedel
2020-03-20  9:06     ` Lu Baolu
2020-03-14  1:07 ` [PATCH v2 3/6] iommu/vt-d: Don't force 32bit devices to uses DMA domain Lu Baolu
2020-03-14  1:07 ` Lu Baolu [this message]
2020-03-14  1:07 ` [PATCH v2 5/6] iommu/vt-d: Add def_domain_type callback Lu Baolu
2020-03-14  1:07 ` [PATCH v2 6/6] iommu/vt-d: Apply per-device dma_ops Lu Baolu

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