[PATCH v4 6/7] xen/arm: smmuv2: Add PCI devices support for SMMUv2

[Stewart Hildebrand <stewart.hildebrand@amd.com>]

From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@amd.com>
---
v3->v4:
* add new device_is_protected check in add_device hook to match SMMUv3 and
  IPMMU-VMSA drivers

v2->v3:
* 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:
* wrap unused function in #ifdef 0
* remove the remove_device() stub since it was submitted separately to the list
  [XEN][PATCH v6 12/19] xen/smmu: Add remove_device callback for smmu_iommu ops
  https://lists.xenproject.org/archives/html/xen-devel/2023-05/msg00204.html
* arm_smmu_(de)assign_dev: return error instead of crashing system
* update condition in arm_smmu_reassign_dev
* style fixup
* add && !is_hardware_domain(d) into condition in arm_smmu_assign_dev()

(cherry picked from commit 0c11a7f65f044c26d87d1e27ac6283ef1f9cfb7a from
 the downstream branch spider-master from
 https://github.com/xen-troops/xen.git)
---

This is a file imported from Linux with modifications for Xen. What should be
the coding style for Xen modifications?
---
 xen/drivers/passthrough/arm/smmu.c | 120 ++++++++++++++++++++++++-----
 1 file changed, 99 insertions(+), 21 deletions(-)

diff --git a/xen/drivers/passthrough/arm/smmu.c b/xen/drivers/passthrough/arm/smmu.c
index d874417958b5..edb5345fb1cd 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -134,8 +134,20 @@ typedef enum irqreturn irqreturn_t;
 /* Device logger functions
  * TODO: Handle PCI
  */
-#define dev_print(dev, lvl, fmt, ...)						\
-	 printk(lvl "smmu: %s: " fmt, dt_node_full_name(dev_to_dt(dev)), ## __VA_ARGS__)
+#ifndef CONFIG_HAS_PCI
+#define dev_print(dev, lvl, fmt, ...)    \
+    printk(lvl "smmu: %s: " fmt, dev_name(dev), ## __VA_ARGS__)
+#else
+#define dev_print(dev, lvl, fmt, ...) ({                                \
+    if ( !dev_is_pci((dev)) )                                           \
+        printk(lvl "smmu: %s: " fmt, dev_name((dev)), ## __VA_ARGS__);  \
+    else                                                                \
+    {                                                                   \
+        struct pci_dev *pdev = dev_to_pci((dev));                       \
+        printk(lvl "smmu: %pp: " fmt, &pdev->sbdf, ## __VA_ARGS__);     \
+    }                                                                   \
+})
+#endif
 
 #define dev_dbg(dev, fmt, ...) dev_print(dev, XENLOG_DEBUG, fmt, ## __VA_ARGS__)
 #define dev_notice(dev, fmt, ...) dev_print(dev, XENLOG_INFO, fmt, ## __VA_ARGS__)
@@ -187,6 +199,7 @@ static void __iomem *devm_ioremap_resource(struct device *dev,
  * Xen: PCI functions
  * TODO: It should be implemented when PCI will be supported
  */
+#if 0 /* unused */
 #define to_pci_dev(dev)	(NULL)
 static inline int pci_for_each_dma_alias(struct pci_dev *pdev,
 					 int (*fn) (struct pci_dev *pdev,
@@ -196,6 +209,7 @@ static inline int pci_for_each_dma_alias(struct pci_dev *pdev,
 	BUG();
 	return 0;
 }
+#endif
 
 /* Xen: misc */
 #define PHYS_MASK_SHIFT		PADDR_BITS
@@ -631,7 +645,7 @@ struct arm_smmu_master_cfg {
 	for (i = 0; idx = cfg->smendx[i], i < num; ++i)
 
 struct arm_smmu_master {
-	struct device_node		*of_node;
+	struct device			*dev;
 	struct rb_node			node;
 	struct arm_smmu_master_cfg	cfg;
 };
@@ -723,7 +737,7 @@ arm_smmu_get_fwspec(struct arm_smmu_master_cfg *cfg)
 {
 	struct arm_smmu_master *master = container_of(cfg,
 			                                      struct arm_smmu_master, cfg);
-	return dev_iommu_fwspec_get(&master->of_node->dev);
+	return dev_iommu_fwspec_get(master->dev);
 }
 
 static void parse_driver_options(struct arm_smmu_device *smmu)
@@ -756,7 +770,7 @@ static struct device_node *dev_get_dev_node(struct device *dev)
 }
 
 static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu,
-						struct device_node *dev_node)
+						struct device *dev)
 {
 	struct rb_node *node = smmu->masters.rb_node;
 
@@ -765,9 +779,9 @@ static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu,
 
 		master = container_of(node, struct arm_smmu_master, node);
 
-		if (dev_node < master->of_node)
+		if (dev < master->dev)
 			node = node->rb_left;
-		else if (dev_node > master->of_node)
+		else if (dev > master->dev)
 			node = node->rb_right;
 		else
 			return master;
@@ -802,9 +816,9 @@ static int insert_smmu_master(struct arm_smmu_device *smmu,
 			= container_of(*new, struct arm_smmu_master, node);
 
 		parent = *new;
-		if (master->of_node < this->of_node)
+		if (master->dev < this->dev)
 			new = &((*new)->rb_left);
-		else if (master->of_node > this->of_node)
+		else if (master->dev > this->dev)
 			new = &((*new)->rb_right);
 		else
 			return -EEXIST;
@@ -823,18 +837,24 @@ static int arm_smmu_dt_add_device_legacy(struct arm_smmu_device *smmu,
 	struct arm_smmu_master *master;
 	struct device_node *dev_node = dev_get_dev_node(dev);
 
-	master = find_smmu_master(smmu, dev_node);
+	master = find_smmu_master(smmu, dev);
 	if (master) {
 		dev_err(dev,
 			"rejecting multiple registrations for master device %s\n",
-			dev_node->name);
+			dev_node ? dev_node->name : "");
 		return -EBUSY;
 	}
 
 	master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
 	if (!master)
 		return -ENOMEM;
-	master->of_node = dev_node;
+	master->dev = dev;
+
+	if ( device_is_protected(dev) )
+	{
+		dev_err(dev, "Already added to SMMU\n");
+		return -EEXIST;
+	}
 
 	/* Xen: Let Xen know that the device is protected by an SMMU */
 	device_set_protected(dev);
@@ -844,7 +864,7 @@ static int arm_smmu_dt_add_device_legacy(struct arm_smmu_device *smmu,
 		     (fwspec->ids[i] >= smmu->num_mapping_groups)) {
 			dev_err(dev,
 				"stream ID for master device %s greater than maximum allowed (%d)\n",
-				dev_node->name, smmu->num_mapping_groups);
+				dev_node ? dev_node->name : "", smmu->num_mapping_groups);
 			return -ERANGE;
 		}
 		master->cfg.smendx[i] = INVALID_SMENDX;
@@ -880,6 +900,21 @@ static int arm_smmu_dt_add_device_generic(u8 devfn, struct device *dev)
 	struct arm_smmu_device *smmu;
 	struct iommu_fwspec *fwspec;
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+		int ret;
+
+		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 == NULL)
 		return -ENXIO;
@@ -911,11 +946,10 @@ static struct arm_smmu_device *find_smmu_for_device(struct device *dev)
 {
 	struct arm_smmu_device *smmu;
 	struct arm_smmu_master *master = NULL;
-	struct device_node *dev_node = dev_get_dev_node(dev);
 
 	spin_lock(&arm_smmu_devices_lock);
 	list_for_each_entry(smmu, &arm_smmu_devices, list) {
-		master = find_smmu_master(smmu, dev_node);
+		master = find_smmu_master(smmu, dev);
 		if (master)
 			break;
 	}
@@ -2007,6 +2041,7 @@ static bool arm_smmu_capable(enum iommu_cap cap)
 }
 #endif
 
+#if 0 /* Not used */
 static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, void *data)
 {
 	*((u16 *)data) = alias;
@@ -2017,6 +2052,7 @@ static void __arm_smmu_release_pci_iommudata(void *data)
 {
 	kfree(data);
 }
+#endif
 
 static int arm_smmu_add_device(struct device *dev)
 {
@@ -2024,12 +2060,13 @@ static int arm_smmu_add_device(struct device *dev)
 	struct arm_smmu_master_cfg *cfg;
 	struct iommu_group *group;
 	void (*releasefn)(void *) = NULL;
-	int ret;
 
 	smmu = find_smmu_for_device(dev);
 	if (!smmu)
 		return -ENODEV;
 
+	/* There is no need to distinguish here, thanks to PCI-IOMMU DT bindings */
+#if 0
 	if (dev_is_pci(dev)) {
 		struct pci_dev *pdev = to_pci_dev(dev);
 		struct iommu_fwspec *fwspec;
@@ -2054,10 +2091,12 @@ static int arm_smmu_add_device(struct device *dev)
 				       &fwspec->ids[0]);
 		releasefn = __arm_smmu_release_pci_iommudata;
 		cfg->smmu = smmu;
-	} else {
+	} else
+#endif
+	{
 		struct arm_smmu_master *master;
 
-		master = find_smmu_master(smmu, dev->of_node);
+		master = find_smmu_master(smmu, dev);
 		if (!master) {
 			return -ENODEV;
 		}
@@ -2725,6 +2764,27 @@ static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
 			return -ENOMEM;
 	}
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) && !is_hardware_domain(d) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		printk(XENLOG_INFO "Assigning device %04x:%02x:%02x.%u to dom%d\n",
+		       pdev->seg, pdev->bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+		       d->domain_id);
+
+		if ( devfn != pdev->devfn || pdev->domain == d )
+			return 0;
+
+		list_move(&pdev->domain_list, &d->pdev_list);
+		pdev->domain = d;
+
+		/* dom_io is used as a sentinel for quarantined devices */
+		if ( d == dom_io )
+			return 0;
+	}
+#endif
+
 	if (!dev_iommu_group(dev)) {
 		ret = arm_smmu_add_device(dev);
 		if (ret)
@@ -2774,11 +2834,29 @@ out:
 	return ret;
 }
 
-static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
+static int arm_smmu_deassign_dev(struct domain *d, u8 devfn, struct device *dev)
 {
 	struct iommu_domain *domain = dev_iommu_domain(dev);
 	struct arm_smmu_xen_domain *xen_domain;
 
+#ifdef CONFIG_HAS_PCI
+	if ( dev_is_pci(dev) )
+	{
+		struct pci_dev *pdev = dev_to_pci(dev);
+
+		printk(XENLOG_INFO "Deassigning device %04x:%02x:%02x.%u from dom%d\n",
+		       pdev->seg, pdev->bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+		       d->domain_id);
+
+		if ( devfn != pdev->devfn )
+			return 0;
+
+		/* dom_io is used as a sentinel for quarantined devices */
+		if ( d == dom_io )
+			return 0;
+	}
+#endif
+
 	xen_domain = dom_iommu(d)->arch.priv;
 
 	if (!domain || domain->priv->cfg.domain != d) {
@@ -2806,13 +2884,13 @@ 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) )
+	if ( t && !is_hardware_domain(t) && t != dom_io )
 		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;
 
-- 
2.40.1