Arm Fast Models are still implementing legacy virtio-pci devices behind
the SMMU, which continue to be problematic as "real hardware" devices
(from the point of view of the simulated system) without the mitigating
VIRTIO_F_ACCESS_PLATFORM feature.

Since we now have the ability to force passthrough on a device-specific
basis, let's use it to work around this particular oddity so that people
who just want to boot Linux on a model don't have to fiddle around with
things to avoid the SMMU getting in the way by default (and I don't have
to keep telling them which things...)

Signed-off-by: Robin Murphy <robin.mur...@arm.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c 
b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 54b2f27b81d4..13cf16e8f45b 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2649,6 +2649,20 @@ static int arm_smmu_dev_disable_feature(struct device 
*dev,
        }
 }
 
+static int arm_smmu_def_domain_type(struct device *dev)
+{
+       if (dev_is_pci(dev)) {
+               struct pci_dev *pdev = to_pci_dev(dev);
+
+               /* Legacy virtio-block devices on Arm Fast Models */
+               if (pdev->vendor == 0x1af4 && pdev->device == 0x1001 &&
+                   pdev->subsystem_vendor == 0x00ff && pdev->subsystem_device 
== 0x0002)
+                       return IOMMU_DOMAIN_IDENTITY;
+       }
+
+       return 0;
+}
+
 static struct iommu_ops arm_smmu_ops = {
        .capable                = arm_smmu_capable,
        .domain_alloc           = arm_smmu_domain_alloc,
@@ -2673,6 +2687,7 @@ static struct iommu_ops arm_smmu_ops = {
        .sva_bind               = arm_smmu_sva_bind,
        .sva_unbind             = arm_smmu_sva_unbind,
        .sva_get_pasid          = arm_smmu_sva_get_pasid,
+       .def_domain_type        = arm_smmu_def_domain_type,
        .pgsize_bitmap          = -1UL, /* Restricted during device attach */
        .owner                  = THIS_MODULE,
 };
-- 
2.25.1

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