iommu/s390: handle IOAT registration based on domain

At this point, the dma_table is really a property of the s390-iommu
domain.  Rather than checking its contents elsewhere in the codebase,
move the code that registers the table with firmware into
s390-iommu and make a decision what to register with firmware based
upon the type of domain in use for the device in question.

Tested-by: Niklas Schnelle <schnelle@linux.ibm.com>
Reviewed-by: Niklas Schnelle <schnelle@linux.ibm.com>
Signed-off-by: Matthew Rosato <mjrosato@linux.ibm.com>
Link: https://lore.kernel.org/r/20250212213418.182902-4-mjrosato@linux.ibm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

arch/s390/include/asm/pci.h

@@ -217,6 +217,7 @@ extern struct airq_iv *zpci_aif_sbv;
 struct zpci_dev *zpci_create_device(u32 fid, u32 fh, enum zpci_state state);
 int zpci_add_device(struct zpci_dev *zdev);
 int zpci_enable_device(struct zpci_dev *);
+int zpci_reenable_device(struct zpci_dev *zdev);
 int zpci_disable_device(struct zpci_dev *);
 int zpci_scan_configured_device(struct zpci_dev *zdev, u32 fh);
 int zpci_deconfigure_device(struct zpci_dev *zdev);
@@ -245,6 +246,7 @@ void update_uid_checking(bool new);
 /* IOMMU Interface */
 int zpci_init_iommu(struct zpci_dev *zdev);
 void zpci_destroy_iommu(struct zpci_dev *zdev);
+int zpci_iommu_register_ioat(struct zpci_dev *zdev, u8 *status);
 
 #ifdef CONFIG_PCI
 static inline bool zpci_use_mio(struct zpci_dev *zdev)

arch/s390/kvm/pci.c

@@ -433,7 +433,6 @@ static void kvm_s390_pci_dev_release(struct zpci_dev *zdev)
 static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm)
 {
 	struct zpci_dev *zdev = opaque;
-	u8 status;
 	int rc;
 
 	if (!zdev)
@@ -480,13 +479,7 @@ static int kvm_s390_pci_register_kvm(void *opaque, struct kvm *kvm)
 	 */
 	zdev->gisa = (u32)virt_to_phys(&kvm->arch.sie_page2->gisa);
 
-	rc = zpci_enable_device(zdev);
-	if (rc)
-		goto clear_gisa;
-
-	/* Re-register the IOMMU that was already created */
-	rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-				virt_to_phys(zdev->dma_table), &status);
+	rc = zpci_reenable_device(zdev);
 	if (rc)
 		goto clear_gisa;
 
@@ -516,7 +509,6 @@ static void kvm_s390_pci_unregister_kvm(void *opaque)
 {
 	struct zpci_dev *zdev = opaque;
 	struct kvm *kvm;
-	u8 status;
 
 	if (!zdev)
 		return;
@@ -550,12 +542,7 @@ static void kvm_s390_pci_unregister_kvm(void *opaque)
 			goto out;
 	}
 
-	if (zpci_enable_device(zdev))
-		goto out;
-
-	/* Re-register the IOMMU that was already created */
-	zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-			   virt_to_phys(zdev->dma_table), &status);
+	zpci_reenable_device(zdev);
 
 out:
 	spin_lock(&kvm->arch.kzdev_list_lock);

arch/s390/pci/pci.c

@@ -124,14 +124,13 @@ int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
 	struct zpci_fib fib = {0};
 	u8 cc;
 
-	WARN_ON_ONCE(iota & 0x3fff);
 	fib.pba = base;
 	/* Work around off by one in ISM virt device */
 	if (zdev->pft == PCI_FUNC_TYPE_ISM && limit > base)
 		fib.pal = limit + (1 << 12);
 	else
 		fib.pal = limit;
-	fib.iota = iota | ZPCI_IOTA_RTTO_FLAG;
+	fib.iota = iota;
 	fib.gd = zdev->gisa;
 	cc = zpci_mod_fc(req, &fib, status);
 	if (cc)
@@ -690,6 +689,23 @@ int zpci_enable_device(struct zpci_dev *zdev)
 }
 EXPORT_SYMBOL_GPL(zpci_enable_device);
 
+int zpci_reenable_device(struct zpci_dev *zdev)
+{
+	u8 status;
+	int rc;
+
+	rc = zpci_enable_device(zdev);
+	if (rc)
+		return rc;
+
+	rc = zpci_iommu_register_ioat(zdev, &status);
+	if (rc)
+		zpci_disable_device(zdev);
+
+	return rc;
+}
+EXPORT_SYMBOL_GPL(zpci_reenable_device);
+
 int zpci_disable_device(struct zpci_dev *zdev)
 {
 	u32 fh = zdev->fh;
@@ -739,7 +755,6 @@ EXPORT_SYMBOL_GPL(zpci_disable_device);
  */
 int zpci_hot_reset_device(struct zpci_dev *zdev)
 {
-	u8 status;
 	int rc;
 
 	lockdep_assert_held(&zdev->state_lock);
@@ -758,19 +773,9 @@ int zpci_hot_reset_device(struct zpci_dev *zdev)
 			return rc;
 	}
 
-	rc = zpci_enable_device(zdev);
-	if (rc)
-		return rc;
-
-	if (zdev->dma_table)
-		rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-					virt_to_phys(zdev->dma_table), &status);
-	if (rc) {
-		zpci_disable_device(zdev);
-		return rc;
-	}
+	rc = zpci_reenable_device(zdev);
 
-	return 0;
+	return rc;
 }
 
 /**

arch/s390/pci/pci_sysfs.c

@@ -52,7 +52,6 @@ static DEVICE_ATTR_RO(mio_enabled);
 
 static int _do_recover(struct pci_dev *pdev, struct zpci_dev *zdev)
 {
-	u8 status;
 	int ret;
 
 	pci_stop_and_remove_bus_device(pdev);
@@ -70,16 +69,8 @@ static int _do_recover(struct pci_dev *pdev, struct zpci_dev *zdev)
 			return ret;
 	}
 
-	ret = zpci_enable_device(zdev);
-	if (ret)
-		return ret;
+	ret = zpci_reenable_device(zdev);
 
-	if (zdev->dma_table) {
-		ret = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-					 virt_to_phys(zdev->dma_table), &status);
-		if (ret)
-			zpci_disable_device(zdev);
-	}
 	return ret;
 }
 

drivers/iommu/s390-iommu.c

@@ -381,6 +381,46 @@ static void zdev_s390_domain_update(struct zpci_dev *zdev,
 	spin_unlock_irqrestore(&zdev->dom_lock, flags);
 }
 
+static int s390_iommu_domain_reg_ioat(struct zpci_dev *zdev,
+				      struct iommu_domain *domain, u8 *status)
+{
+	struct s390_domain *s390_domain;
+	int rc = 0;
+	u64 iota;
+
+	switch (domain->type) {
+	case IOMMU_DOMAIN_IDENTITY:
+		rc = zpci_register_ioat(zdev, 0, zdev->start_dma,
+					zdev->end_dma, 0, status);
+		break;
+	case IOMMU_DOMAIN_BLOCKED:
+		/* Nothing to do in this case */
+		break;
+	default:
+		s390_domain = to_s390_domain(domain);
+		iota = virt_to_phys(s390_domain->dma_table) |
+		       ZPCI_IOTA_RTTO_FLAG;
+		rc = zpci_register_ioat(zdev, 0, zdev->start_dma,
+					zdev->end_dma, iota, status);
+	}
+
+	return rc;
+}
+
+int zpci_iommu_register_ioat(struct zpci_dev *zdev, u8 *status)
+{
+	unsigned long flags;
+	int rc;
+
+	spin_lock_irqsave(&zdev->dom_lock, flags);
+
+	rc = s390_iommu_domain_reg_ioat(zdev, zdev->s390_domain, status);
+
+	spin_unlock_irqrestore(&zdev->dom_lock, flags);
+
+	return rc;
+}
+
 static int blocking_domain_attach_device(struct iommu_domain *domain,
 					 struct device *dev)
 {
@@ -422,8 +462,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	blocking_domain_attach_device(&blocking_domain, dev);
 
 	/* If we fail now DMA remains blocked via blocking domain */
-	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-				virt_to_phys(s390_domain->dma_table), &status);
+	cc = s390_iommu_domain_reg_ioat(zdev, domain, &status);
 	if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
 		return -EIO;
 	zdev->dma_table = s390_domain->dma_table;