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[v7,5/8] xen/arm: smmuv3: Add PCI devices support for SMMUv3

Message ID dbbf957ced225e24a1e7c3e68a17201f448e4633.1738665272.git.mykyta_poturai@epam.com (mailing list archive)
State New
Headers show
Series SMMU handling for PCIe Passthrough on ARM | expand

Commit Message

Mykyta Poturai Feb. 4, 2025, 1:54 p.m. UTC 
From: Rahul Singh <rahul.singh@arm.com>

Implement support for PCI devices in the SMMU driver. Trigger iommu-map
parsing when new PCI device is added. Add checks to assign/deassign
functions to ensure PCI devices are handled correctly. Implement basic
quarantining.

All pci devices are automatically assigned to hardware domain if it exists
to ensure it can probe them.

TODO:
Implement scratch page quarantining support.

Signed-off-by: Rahul Singh <rahul.singh@arm.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
Signed-off-by: Mykyta Poturai <mykyta_poturai@epam.com>
---
v6->v7:
* address TODO: use d->pci_lock in arm_smmu_assign_dev()
* remove !is_hardware_domain and pdev->domain == d checks in assign to
  support future dom0less use case when dom0 is using vPCI
* check if pdev->domain exists before assigning to it
* don't print ""
* change assign logic to remove reassign reimplementation
* explain pdev->devfn check
* make reassign check stricter and update comment

v5->v6:
* check for hardware_domain == NULL (dom0less test case)
* locking: assign pdev->domain before list_add()

v4->v5:
* deassign from hwdom
* add TODO regarding locking
* fixup after dropping ("xen/arm: Move is_protected flag to struct device")

v3->v4:
* no change

v2->v3:
* rebase
* invoke iommu_add_pci_sideband_ids() from add_device hook

v1->v2:
* ignore add_device/assign_device/reassign_device calls for phantom functions
  (i.e. devfn != pdev->devfn)

downstream->v1:
* rebase
* move 2 replacements of s/dt_device_set_protected(dev_to_dt(dev))/device_set_protected(dev)/
  from this commit to ("xen/arm: Move is_protected flag to struct device")
  so as to not break ability to bisect
* adjust patch title (remove stray space)
* arm_smmu_(de)assign_dev: return error instead of crashing system
* remove arm_smmu_remove_device() stub
* update condition in arm_smmu_reassign_dev
* style fixup

(cherry picked from commit 7ed6c3ab250d899fe6e893a514278e406a2893e8 from
 the downstream branch poc/pci-passthrough from
 https://gitlab.com/xen-project/people/bmarquis/xen-arm-poc.git)
---
 xen/drivers/passthrough/arm/smmu-v3.c | 117 +++++++++++++++++++++++---
 1 file changed, 106 insertions(+), 11 deletions(-)
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Patch

diff --git a/xen/drivers/passthrough/arm/smmu-v3.c b/xen/drivers/passthrough/arm/smmu-v3.c
index cee5724022..9c7c13f800 100644
--- a/xen/drivers/passthrough/arm/smmu-v3.c
+++ b/xen/drivers/passthrough/arm/smmu-v3.c
@@ -1467,14 +1467,35 @@  static bool arm_smmu_sid_in_range(struct arm_smmu_device *smmu, u32 sid)
 }
 /* Forward declaration */
 static struct arm_smmu_device *arm_smmu_get_by_dev(const struct device *dev);
+static int arm_smmu_assign_dev(struct domain *d, u8 devfn, struct device *dev,
+			       u32 flag);
+static int arm_smmu_deassign_dev(struct domain *d, uint8_t devfn,
+				 struct device *dev);
 
 static int arm_smmu_add_device(u8 devfn, struct device *dev)
 {
 	int i, ret;
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_master *master;
-	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct iommu_fwspec *fwspec;
+
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+		int ret;
+				
+		/* Ignore calls for phantom functions */
+		if ( devfn != pdev->devfn )
+			return 0;
+
+		ret = iommu_add_pci_sideband_ids(pdev);
+		if ( ret < 0 )
+			iommu_fwspec_free(dev);
+	}
+#endif
 
+	fwspec = dev_iommu_fwspec_get(dev);
 	if (!fwspec)
 		return -ENODEV;
 
@@ -1519,17 +1540,38 @@  static int arm_smmu_add_device(u8 devfn, struct device *dev)
 	 */
 	arm_smmu_enable_pasid(master);
 
-	if (dt_device_is_protected(dev_to_dt(dev))) {
-		dev_err(dev, "Already added to SMMUv3\n");
-		return -EEXIST;
-	}
+	if ( !dev_is_pci(dev) )
+	{
+		if (dt_device_is_protected(dev_to_dt(dev))) {
+			dev_err(dev, "Already added to SMMUv3\n");
+			return -EEXIST;
+		}
 
-	/* Let Xen know that the master device is protected by an IOMMU. */
-	dt_device_set_protected(dev_to_dt(dev));
+		/* Let Xen know that the master device is protected by an IOMMU. */
+		dt_device_set_protected(dev_to_dt(dev));
+	}
 
 	dev_info(dev, "Added master device (SMMUv3 %s StreamIds %u)\n",
 			dev_name(fwspec->iommu_dev), fwspec->num_ids);
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		/*
+		 * During PHYSDEVOP_pci_device_add, Xen does not assign the
+		 * device, so we must do it here.
+		 */
+		if ( pdev->domain )
+		{
+			ret = arm_smmu_assign_dev(pdev->domain, devfn, dev, 0);
+			if (ret)
+				goto err_free_master;
+		}
+	}
+#endif
+
 	return 0;
 
 err_free_master:
@@ -2622,6 +2664,42 @@  static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
 	struct arm_smmu_domain *smmu_domain;
 	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		/* Ignore calls for phantom functions */
+		if ( devfn != pdev->devfn )
+			return 0;
+
+		ASSERT(pcidevs_locked());
+
+		write_lock(&pdev->domain->pci_lock);
+		list_del(&pdev->domain_list);
+		write_unlock(&pdev->domain->pci_lock);
+
+		pdev->domain = d;
+
+		write_lock(&d->pci_lock);
+		list_add(&pdev->domain_list, &d->pdev_list);
+		write_unlock(&d->pci_lock);
+
+		/* dom_io is used as a sentinel for quarantined devices */
+		if ( d == dom_io )
+		{
+			struct arm_smmu_master *master = dev_iommu_priv_get(dev);
+			if ( !iommu_quarantine )
+				return 0;
+
+			if ( master && master->domain )
+				arm_smmu_deassign_dev(master->domain->d, devfn, dev);
+
+			return 0;
+		}
+	}
+#endif
+
 	spin_lock(&xen_domain->lock);
 
 	/*
@@ -2655,7 +2733,7 @@  out:
 	return ret;
 }
 
-static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
+static int arm_smmu_deassign_dev(struct domain *d, uint8_t devfn, struct device *dev)
 {
 	struct iommu_domain *io_domain = arm_smmu_get_domain(d, dev);
 	struct arm_smmu_xen_domain *xen_domain = dom_iommu(d)->arch.priv;
@@ -2667,6 +2745,21 @@  static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
 		return -ESRCH;
 	}
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		/* Ignore calls for phantom functions */
+		if ( devfn != pdev->devfn )
+			return 0;
+
+		/* dom_io is used as a sentinel for quarantined devices */
+		if ( d == dom_io )
+			return 0;
+	}
+#endif
+
 	spin_lock(&xen_domain->lock);
 
 	arm_smmu_detach_dev(master);
@@ -2685,14 +2778,16 @@  static int arm_smmu_reassign_dev(struct domain *s, struct domain *t,
 {
 	int ret = 0;
 
-	/* Don't allow remapping on other domain than hwdom */
-	if ( t && !is_hardware_domain(t) )
+	/* Don't allow remapping on other domain than hwdom
+	 * or dom_io for PCI devices
+	 */
+	if ( t && !is_hardware_domain(t) && (t != dom_io || !dev_is_pci(dev)) )
 		return -EPERM;
 
 	if (t == s)
 		return 0;
 
-	ret = arm_smmu_deassign_dev(s, dev);
+	ret = arm_smmu_deassign_dev(s, devfn, dev);
 	if (ret)
 		return ret;