iommu/amd: Implement global identity domain

Implement global identity domain. All device groups in identity domain
will share this domain.

In attach device path, based on device capability it will allocate per
device domain ID and GCR3 table. So that it can support SVA.

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20241028093810.5901-11-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

Author: hegdevasant

drivers/iommu/amd/amd_iommu.h

@@ -46,6 +46,7 @@ extern int amd_iommu_gpt_level;
 extern unsigned long amd_iommu_pgsize_bitmap;
 
 /* Protection domain ops */
+void amd_iommu_init_identity_domain(void);
 struct protection_domain *protection_domain_alloc(unsigned int type, int nid);
 void protection_domain_free(struct protection_domain *domain);
 struct iommu_domain *amd_iommu_domain_alloc_sva(struct device *dev,

drivers/iommu/amd/init.c

@@ -2164,6 +2164,9 @@ static int __init amd_iommu_init_pci(void)
 	struct amd_iommu_pci_seg *pci_seg;
 	int ret;
 
+	/* Init global identity domain before registering IOMMU */
+	amd_iommu_init_identity_domain();
+
 	for_each_iommu(iommu) {
 		ret = iommu_init_pci(iommu);
 		if (ret) {

drivers/iommu/amd/iommu.c

@@ -74,6 +74,9 @@ struct kmem_cache *amd_iommu_irq_cache;
 
 static void detach_device(struct device *dev);
 
+static int amd_iommu_attach_device(struct iommu_domain *dom,
+				   struct device *dev);
+
 static void set_dte_entry(struct amd_iommu *iommu,
 			  struct iommu_dev_data *dev_data);
 
@@ -2263,6 +2266,14 @@ void protection_domain_free(struct protection_domain *domain)
 	kfree(domain);
 }
 
+static void protection_domain_init(struct protection_domain *domain, int nid)
+{
+	spin_lock_init(&domain->lock);
+	INIT_LIST_HEAD(&domain->dev_list);
+	INIT_LIST_HEAD(&domain->dev_data_list);
+	domain->iop.pgtbl.cfg.amd.nid = nid;
+}
+
 struct protection_domain *protection_domain_alloc(unsigned int type, int nid)
 {
 	struct protection_domain *domain;
@@ -2277,10 +2288,7 @@ struct protection_domain *protection_domain_alloc(unsigned int type, int nid)
 		return NULL;
 	}
 
-	spin_lock_init(&domain->lock);
-	INIT_LIST_HEAD(&domain->dev_list);
-	INIT_LIST_HEAD(&domain->dev_data_list);
-	domain->iop.pgtbl.cfg.amd.nid = nid;
+	protection_domain_init(domain, nid);
 
 	return domain;
 }
@@ -2471,6 +2479,25 @@ static struct iommu_domain blocked_domain = {
 	}
 };
 
+static struct protection_domain identity_domain;
+
+static const struct iommu_domain_ops identity_domain_ops = {
+	.attach_dev = amd_iommu_attach_device,
+};
+
+void amd_iommu_init_identity_domain(void)
+{
+	struct iommu_domain *domain = &identity_domain.domain;
+
+	domain->type = IOMMU_DOMAIN_IDENTITY;
+	domain->ops = &identity_domain_ops;
+	domain->owner = &amd_iommu_ops;
+
+	identity_domain.id = domain_id_alloc();
+
+	protection_domain_init(&identity_domain, NUMA_NO_NODE);
+}
+
 static int amd_iommu_attach_device(struct iommu_domain *dom,
 				   struct device *dev)
 {
@@ -2869,6 +2896,7 @@ static int amd_iommu_dev_disable_feature(struct device *dev,
 const struct iommu_ops amd_iommu_ops = {
 	.capable = amd_iommu_capable,
 	.blocked_domain = &blocked_domain,
+	.identity_domain = &identity_domain.domain,
 	.domain_alloc = amd_iommu_domain_alloc,
 	.domain_alloc_user = amd_iommu_domain_alloc_user,
 	.domain_alloc_sva = amd_iommu_domain_alloc_sva,