[PATCH v8 0/6] iommu/s390: Fixes related to attach and aperture handling

[PATCH v8 0/6] iommu/s390: Fixes related to attach and aperture handling

[Niklas Schnelle]

Hi All,

This is v8 of a follow up to Matt's recent series[0] where he tackled
a race that turned out to be outside of the s390 IOMMU driver itself as
well as duplicate device attachments. Instead of actively checking for
duplicates we instead detach from any previous domain on attach. From my
cursory reading of the code this seems to be what the Intel IOMMU driver is
doing as well.

Moreover we drop the attempt to re-attach the device to its previous IOMMU
domain on failure. This was fragile, unlikely to help and unexpected for
calling code. Thanks Jason for the suggestion.

We can also get rid of struct s390_domain_device entirely if we instead
thread the list through the attached struct zpci_devs. This saves us from
having to allocate during attach and gets rid of one level of indirection
during IOMMU operations.

Additionally 3 more fixes have been added in v3 that weren't in v2 of this
series. One is for a potential situation where the aperture of a domain
could shrink and leave invalid translations. The next one fixes an off by
one in checking validity of an IOVA and the last one fixes a wrong value
for pgsize_bitmap.

In v4 we also add a patch changing to the map_pages()/unmap_pages()
interface in order to prevent a performance regression due to the
pgsize_bitmap change.

*Note*:
This series is applies on top of v6.1-rc2. It is also available as branch
iommu_fixes_v8 with the GPG signed tag s390_iommu_fixes_v8 on my niks/linux.git
on git.kernel.org[1].

Best regards,
Niklas

Changes since v7:
- Rebased on v6.1-rc2 adding gfp flags in iommu_alloc_resv_region()
- Added Jason's R-bs

Changes since v6:
- Rebased on top of v6.1-rc1 which now includes all prerequisites
- Added Matt's R-b

Changes since v5:
- Only set zdev->dma_table once zpci_register_ioat() has succeeded like
  we correctly did in v4 (Matt)
- In patch 3 WARN_ON() aperture violation in .unmap_pages (Matt)
- In patch 3 return after WARN_ON() check for aperture in attach

Changes since v4:
- Add patch to change to the map_pages()/unmap_pages() API to prevent
  a performance regression from the pgsize_bitmap change (Robin)
- In patch 1 unregister IOAT on error (Matt)
- Turn the aperture check in attach into a WARN_ON() in patch 3 (Jason)

Changes since v3:
- Drop s390_domain from __s390_iommu_detach_device() (Jason)
- WARN_ON() mismatched domain in s390_iommu_detach_device() (Jason)
- Use __s390_iommu_detach_device() in s390_iommu_release_device() (Jason)
- Make aperture check resistant against overflow (Jason)

Changes since v2:
- The patch removing the unused bus_next field has been spun out and
  already made it into the s390 feature branch on git.kernel.org
- Make __s390_iommu_detach_device() return void (Jason)
- Remove the re-attach on failure dance as it is unlikely to help
  and complicates debug and recovery (Jason)
- Ignore attempts to detach from domain that is not the active one
- Add patch to fix potential shrinking of the aperture and use
  reserved ranges per device instead of the aperture to respect
  IOVA range restrictions (Jason)
- Add a fix for an off by one error on checking an IOVA against
  the aperture
- Add a fix for wrong pgsize_bitmap

Changes since v1:
- After patch 3 we don't have to search in the devices list on detach as
  we alreadz have hold of the zpci_dev (Jason)
- Add a WARN_ON() if somehow ended up detaching a device from a domain that
  isn't the device's current domain.
- Removed the iteration and list delete from s390_domain_free() instead
  just WARN_ON() when we're freeing without having detached
- The last two points should help catching sequencing errors much more
  quickly in the future.

[0] https://lore.kernel.org/linux-iommu/20220831201236.77595-1-mjrosato@linux.ibm.com/
[1] https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git

Niklas Schnelle (6):
  iommu/s390: Fix duplicate domain attachments
  iommu/s390: Get rid of s390_domain_device
  iommu/s390: Fix potential s390_domain aperture shrinking
  iommu/s390: Fix incorrect aperture check
  iommu/s390: Fix incorrect pgsize_bitmap
  iommu/s390: Implement map_pages()/unmap_pages() instead of
    map()/unmap()

 arch/s390/include/asm/pci.h |   1 +
 drivers/iommu/s390-iommu.c  | 223 +++++++++++++++++-------------------
 2 files changed, 109 insertions(+), 115 deletions(-)

-- 
2.34.1

[PATCH v8 1/6] iommu/s390: Fix duplicate domain attachments

[Niklas Schnelle]

Since commit fa7e9ecc5e1c ("iommu/s390: Tolerate repeat attach_dev
calls") we can end up with duplicates in the list of devices attached to
a domain. This is inefficient and confusing since only one domain can
actually be in control of the IOMMU translations for a device. Fix this
by detaching the device from the previous domain, if any, on attach.
Add a WARN_ON() in case we still have attached devices on freeing the
domain. While here remove the re-attach on failure dance as it was
determined to be unlikely to help and may confuse debug and recovery.

Fixes: fa7e9ecc5e1c ("iommu/s390: Tolerate repeat attach_dev calls")
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
v7->v8:
- Added Jason's R-b
v6->v7:
- Added Matt's R-b
v5->v6:
- Only set zdev->dma_table once zpci_register_ioat() succeeded (Matt)
v4->v5:
- Unregister IOAT and set zdev->dma_table on error (Matt)

 drivers/iommu/s390-iommu.c | 106 ++++++++++++++++---------------------
 1 file changed, 45 insertions(+), 61 deletions(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 3c071782f6f1..c2e5e81d609e 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -79,10 +79,36 @@ static void s390_domain_free(struct iommu_domain *domain)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 
+	WARN_ON(!list_empty(&s390_domain->devices));
 	dma_cleanup_tables(s390_domain->dma_table);
 	kfree(s390_domain);
 }
 
+static void __s390_iommu_detach_device(struct zpci_dev *zdev)
+{
+	struct s390_domain *s390_domain = zdev->s390_domain;
+	struct s390_domain_device *domain_device, *tmp;
+	unsigned long flags;
+
+	if (!s390_domain)
+		return;
+
+	spin_lock_irqsave(&s390_domain->list_lock, flags);
+	list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
+				 list) {
+		if (domain_device->zdev == zdev) {
+			list_del(&domain_device->list);
+			kfree(domain_device);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+
+	zpci_unregister_ioat(zdev, 0);
+	zdev->s390_domain = NULL;
+	zdev->dma_table = NULL;
+}
+
 static int s390_iommu_attach_device(struct iommu_domain *domain,
 				    struct device *dev)
 {
@@ -90,7 +116,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	struct zpci_dev *zdev = to_zpci_dev(dev);
 	struct s390_domain_device *domain_device;
 	unsigned long flags;
-	int cc, rc;
+	int cc, rc = 0;
 
 	if (!zdev)
 		return -ENODEV;
@@ -99,24 +125,18 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	if (!domain_device)
 		return -ENOMEM;
 
-	if (zdev->dma_table && !zdev->s390_domain) {
-		cc = zpci_dma_exit_device(zdev);
-		if (cc) {
-			rc = -EIO;
-			goto out_free;
-		}
-	}
-
 	if (zdev->s390_domain)
-		zpci_unregister_ioat(zdev, 0);
+		__s390_iommu_detach_device(zdev);
+	else if (zdev->dma_table)
+		zpci_dma_exit_device(zdev);
 
-	zdev->dma_table = s390_domain->dma_table;
 	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-				virt_to_phys(zdev->dma_table));
+				virt_to_phys(s390_domain->dma_table));
 	if (cc) {
 		rc = -EIO;
-		goto out_restore;
+		goto out_free;
 	}
+	zdev->dma_table = s390_domain->dma_table;
 
 	spin_lock_irqsave(&s390_domain->list_lock, flags);
 	/* First device defines the DMA range limits */
@@ -127,9 +147,9 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	/* Allow only devices with identical DMA range limits */
 	} else if (domain->geometry.aperture_start != zdev->start_dma ||
 		   domain->geometry.aperture_end != zdev->end_dma) {
-		rc = -EINVAL;
 		spin_unlock_irqrestore(&s390_domain->list_lock, flags);
-		goto out_restore;
+		rc = -EINVAL;
+		goto out_unregister;
 	}
 	domain_device->zdev = zdev;
 	zdev->s390_domain = s390_domain;
@@ -138,14 +158,9 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 
 	return 0;
 
-out_restore:
-	if (!zdev->s390_domain) {
-		zpci_dma_init_device(zdev);
-	} else {
-		zdev->dma_table = zdev->s390_domain->dma_table;
-		zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-				   virt_to_phys(zdev->dma_table));
-	}
+out_unregister:
+	zpci_unregister_ioat(zdev, 0);
+	zdev->dma_table = NULL;
 out_free:
 	kfree(domain_device);
 
@@ -155,32 +170,12 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 static void s390_iommu_detach_device(struct iommu_domain *domain,
 				     struct device *dev)
 {
-	struct s390_domain *s390_domain = to_s390_domain(domain);
 	struct zpci_dev *zdev = to_zpci_dev(dev);
-	struct s390_domain_device *domain_device, *tmp;
-	unsigned long flags;
-	int found = 0;
 
-	if (!zdev)
-		return;
+	WARN_ON(zdev->s390_domain != to_s390_domain(domain));
 
-	spin_lock_irqsave(&s390_domain->list_lock, flags);
-	list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
-				 list) {
-		if (domain_device->zdev == zdev) {
-			list_del(&domain_device->list);
-			kfree(domain_device);
-			found = 1;
-			break;
-		}
-	}
-	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
-
-	if (found && (zdev->s390_domain == s390_domain)) {
-		zdev->s390_domain = NULL;
-		zpci_unregister_ioat(zdev, 0);
-		zpci_dma_init_device(zdev);
-	}
+	__s390_iommu_detach_device(zdev);
+	zpci_dma_init_device(zdev);
 }
 
 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
@@ -198,24 +193,13 @@ static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 static void s390_iommu_release_device(struct device *dev)
 {
 	struct zpci_dev *zdev = to_zpci_dev(dev);
-	struct iommu_domain *domain;
 
 	/*
-	 * This is a workaround for a scenario where the IOMMU API common code
-	 * "forgets" to call the detach_dev callback: After binding a device
-	 * to vfio-pci and completing the VFIO_SET_IOMMU ioctl (which triggers
-	 * the attach_dev), removing the device via
-	 * "echo 1 > /sys/bus/pci/devices/.../remove" won't trigger detach_dev,
-	 * only release_device will be called via the BUS_NOTIFY_REMOVED_DEVICE
-	 * notifier.
-	 *
-	 * So let's call detach_dev from here if it hasn't been called before.
+	 * release_device is expected to detach any domain currently attached
+	 * to the device, but keep it attached to other devices in the group.
 	 */
-	if (zdev && zdev->s390_domain) {
-		domain = iommu_get_domain_for_dev(dev);
-		if (domain)
-			s390_iommu_detach_device(domain, dev);
-	}
+	if (zdev)
+		__s390_iommu_detach_device(zdev);
 }
 
 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
-- 
2.34.1

[PATCH v8 2/6] iommu/s390: Get rid of s390_domain_device

[Niklas Schnelle]

The struct s390_domain_device serves the sole purpose as list entry for
the devices list of a struct s390_domain. As it contains no additional
information besides a list_head and a pointer to the struct zpci_dev we
can simplify things and just thread the device list through struct
zpci_dev directly. This removes the need to allocate during domain
attach and gets rid of one level of indirection during mapping
operations.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
v7->v8:
- Added Jason's R-b
v5->v6:
- On attach failure make sure the IOAT is not registered
  and zdev->dma_table == NULL
- Dropped Jason's R-b

 arch/s390/include/asm/pci.h |  1 +
 drivers/iommu/s390-iommu.c  | 37 +++++++------------------------------
 2 files changed, 8 insertions(+), 30 deletions(-)

diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index 108e732d7b14..15f8714ca9b7 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -117,6 +117,7 @@ struct zpci_bus {
 struct zpci_dev {
 	struct zpci_bus *zbus;
 	struct list_head entry;		/* list of all zpci_devices, needed for hotplug, etc. */
+	struct list_head iommu_list;
 	struct kref kref;
 	struct hotplug_slot hotplug_slot;
 
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index c2e5e81d609e..af83ccde16a4 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -29,11 +29,6 @@ struct s390_domain {
 	spinlock_t		list_lock;
 };
 
-struct s390_domain_device {
-	struct list_head	list;
-	struct zpci_dev		*zdev;
-};
-
 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct s390_domain, domain);
@@ -87,21 +82,13 @@ static void s390_domain_free(struct iommu_domain *domain)
 static void __s390_iommu_detach_device(struct zpci_dev *zdev)
 {
 	struct s390_domain *s390_domain = zdev->s390_domain;
-	struct s390_domain_device *domain_device, *tmp;
 	unsigned long flags;
 
 	if (!s390_domain)
 		return;
 
 	spin_lock_irqsave(&s390_domain->list_lock, flags);
-	list_for_each_entry_safe(domain_device, tmp, &s390_domain->devices,
-				 list) {
-		if (domain_device->zdev == zdev) {
-			list_del(&domain_device->list);
-			kfree(domain_device);
-			break;
-		}
-	}
+	list_del_init(&zdev->iommu_list);
 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 
 	zpci_unregister_ioat(zdev, 0);
@@ -114,17 +101,12 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	struct zpci_dev *zdev = to_zpci_dev(dev);
-	struct s390_domain_device *domain_device;
 	unsigned long flags;
 	int cc, rc = 0;
 
 	if (!zdev)
 		return -ENODEV;
 
-	domain_device = kzalloc(sizeof(*domain_device), GFP_KERNEL);
-	if (!domain_device)
-		return -ENOMEM;
-
 	if (zdev->s390_domain)
 		__s390_iommu_detach_device(zdev);
 	else if (zdev->dma_table)
@@ -132,10 +114,8 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 
 	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 				virt_to_phys(s390_domain->dma_table));
-	if (cc) {
-		rc = -EIO;
-		goto out_free;
-	}
+	if (cc)
+		return -EIO;
 	zdev->dma_table = s390_domain->dma_table;
 
 	spin_lock_irqsave(&s390_domain->list_lock, flags);
@@ -151,9 +131,8 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 		rc = -EINVAL;
 		goto out_unregister;
 	}
-	domain_device->zdev = zdev;
 	zdev->s390_domain = s390_domain;
-	list_add(&domain_device->list, &s390_domain->devices);
+	list_add(&zdev->iommu_list, &s390_domain->devices);
 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 
 	return 0;
@@ -161,8 +140,6 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 out_unregister:
 	zpci_unregister_ioat(zdev, 0);
 	zdev->dma_table = NULL;
-out_free:
-	kfree(domain_device);
 
 	return rc;
 }
@@ -206,10 +183,10 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 				   phys_addr_t pa, dma_addr_t dma_addr,
 				   size_t size, int flags)
 {
-	struct s390_domain_device *domain_device;
 	phys_addr_t page_addr = pa & PAGE_MASK;
 	dma_addr_t start_dma_addr = dma_addr;
 	unsigned long irq_flags, nr_pages, i;
+	struct zpci_dev *zdev;
 	unsigned long *entry;
 	int rc = 0;
 
@@ -234,8 +211,8 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 	}
 
 	spin_lock(&s390_domain->list_lock);
-	list_for_each_entry(domain_device, &s390_domain->devices, list) {
-		rc = zpci_refresh_trans((u64) domain_device->zdev->fh << 32,
+	list_for_each_entry(zdev, &s390_domain->devices, iommu_list) {
+		rc = zpci_refresh_trans((u64)zdev->fh << 32,
 					start_dma_addr, nr_pages * PAGE_SIZE);
 		if (rc)
 			break;
-- 
2.34.1

[PATCH v8 3/6] iommu/s390: Fix potential s390_domain aperture shrinking

[Niklas Schnelle]

The s390 IOMMU driver currently sets the IOMMU domain's aperture to
match the device specific DMA address range of the device that is first
attached. This is not ideal. For one if the domain has no device
attached in the meantime the aperture could be shrunk allowing
translations outside the aperture to exist in the translation tables.
Also this is a bit of a misuse of the aperture which really should
describe what addresses can be translated and not some device specific
limitations.

Instead of misusing the aperture like this we can instead create
reserved ranges for the ranges inaccessible to the attached devices
allowing devices with overlapping ranges to still share an IOMMU domain.
This also significantly simplifies s390_iommu_attach_device() allowing
us to move the aperture check to the beginning of the function and
removing the need to hold the device list's lock to check the aperture.

As we then use the same aperture for all domains and it only depends on
the table properties we can already check zdev->start_dma/end_dma at
probe time and turn the check on attach into a WARN_ON().

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
v7->v8:
- Added Jason's R-b
- Added GFP_KERNEL param to iommu_alloc_resv_region()
v5->v6:
- Return -EINVAL after WARN_ON() in attach
v4->v5:
- Make aperture check in attach a WARN_ON() and fail in probe if
  zdev->start_dma/end_dma doesn't git in aperture  (Jason)

 drivers/iommu/s390-iommu.c | 63 ++++++++++++++++++++++++++------------
 1 file changed, 43 insertions(+), 20 deletions(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index af83ccde16a4..9b3adc61005c 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -62,6 +62,9 @@ static struct iommu_domain *s390_domain_alloc(unsigned domain_type)
 		kfree(s390_domain);
 		return NULL;
 	}
+	s390_domain->domain.geometry.force_aperture = true;
+	s390_domain->domain.geometry.aperture_start = 0;
+	s390_domain->domain.geometry.aperture_end = ZPCI_TABLE_SIZE_RT - 1;
 
 	spin_lock_init(&s390_domain->dma_table_lock);
 	spin_lock_init(&s390_domain->list_lock);
@@ -102,11 +105,15 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	struct zpci_dev *zdev = to_zpci_dev(dev);
 	unsigned long flags;
-	int cc, rc = 0;
+	int cc;
 
 	if (!zdev)
 		return -ENODEV;
 
+	if (WARN_ON(domain->geometry.aperture_start > zdev->end_dma ||
+		domain->geometry.aperture_end < zdev->start_dma))
+		return -EINVAL;
+
 	if (zdev->s390_domain)
 		__s390_iommu_detach_device(zdev);
 	else if (zdev->dma_table)
@@ -118,30 +125,14 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 		return -EIO;
 	zdev->dma_table = s390_domain->dma_table;
 
-	spin_lock_irqsave(&s390_domain->list_lock, flags);
-	/* First device defines the DMA range limits */
-	if (list_empty(&s390_domain->devices)) {
-		domain->geometry.aperture_start = zdev->start_dma;
-		domain->geometry.aperture_end = zdev->end_dma;
-		domain->geometry.force_aperture = true;
-	/* Allow only devices with identical DMA range limits */
-	} else if (domain->geometry.aperture_start != zdev->start_dma ||
-		   domain->geometry.aperture_end != zdev->end_dma) {
-		spin_unlock_irqrestore(&s390_domain->list_lock, flags);
-		rc = -EINVAL;
-		goto out_unregister;
-	}
+	zdev->dma_table = s390_domain->dma_table;
 	zdev->s390_domain = s390_domain;
+
+	spin_lock_irqsave(&s390_domain->list_lock, flags);
 	list_add(&zdev->iommu_list, &s390_domain->devices);
 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
 
 	return 0;
-
-out_unregister:
-	zpci_unregister_ioat(zdev, 0);
-	zdev->dma_table = NULL;
-
-	return rc;
 }
 
 static void s390_iommu_detach_device(struct iommu_domain *domain,
@@ -155,6 +146,30 @@ static void s390_iommu_detach_device(struct iommu_domain *domain,
 	zpci_dma_init_device(zdev);
 }
 
+static void s390_iommu_get_resv_regions(struct device *dev,
+					struct list_head *list)
+{
+	struct zpci_dev *zdev = to_zpci_dev(dev);
+	struct iommu_resv_region *region;
+
+	if (zdev->start_dma) {
+		region = iommu_alloc_resv_region(0, zdev->start_dma, 0,
+						 IOMMU_RESV_RESERVED, GFP_KERNEL);
+		if (!region)
+			return;
+		list_add_tail(&region->list, list);
+	}
+
+	if (zdev->end_dma < ZPCI_TABLE_SIZE_RT - 1) {
+		region = iommu_alloc_resv_region(zdev->end_dma + 1,
+						 ZPCI_TABLE_SIZE_RT - zdev->end_dma - 1,
+						 0, IOMMU_RESV_RESERVED, GFP_KERNEL);
+		if (!region)
+			return;
+		list_add_tail(&region->list, list);
+	}
+}
+
 static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 {
 	struct zpci_dev *zdev;
@@ -164,6 +179,13 @@ static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 
 	zdev = to_zpci_dev(dev);
 
+	if (zdev->start_dma > zdev->end_dma ||
+	    zdev->start_dma > ZPCI_TABLE_SIZE_RT - 1)
+		return ERR_PTR(-EINVAL);
+
+	if (zdev->end_dma > ZPCI_TABLE_SIZE_RT - 1)
+		zdev->end_dma = ZPCI_TABLE_SIZE_RT - 1;
+
 	return &zdev->iommu_dev;
 }
 
@@ -342,6 +364,7 @@ static const struct iommu_ops s390_iommu_ops = {
 	.release_device = s390_iommu_release_device,
 	.device_group = generic_device_group,
 	.pgsize_bitmap = S390_IOMMU_PGSIZES,
+	.get_resv_regions = s390_iommu_get_resv_regions,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= s390_iommu_attach_device,
 		.detach_dev	= s390_iommu_detach_device,
-- 
2.34.1

[PATCH v8 4/6] iommu/s390: Fix incorrect aperture check

[Niklas Schnelle]

The domain->geometry.aperture_end specifies the last valid address treat
it as such when checking if a DMA address is valid.

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
v7->v8:
- Added Jason's R-b
v3->v4:
- Make check robust against overflow (Jason)

 drivers/iommu/s390-iommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 9b3adc61005c..3e601ca6ee0f 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -213,7 +213,7 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 	int rc = 0;
 
 	if (dma_addr < s390_domain->domain.geometry.aperture_start ||
-	    dma_addr + size > s390_domain->domain.geometry.aperture_end)
+	    (dma_addr + size - 1) > s390_domain->domain.geometry.aperture_end)
 		return -EINVAL;
 
 	nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-- 
2.34.1

[PATCH v8 5/6] iommu/s390: Fix incorrect pgsize_bitmap

[Niklas Schnelle]

The .pgsize_bitmap property of struct iommu_ops is not a page mask but
rather has a bit set for each size of pages the IOMMU supports. As the
comment correctly pointed out at this moment the code only support 4K
pages so simply use SZ_4K here.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/iommu/s390-iommu.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 3e601ca6ee0f..104dfbec1037 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -12,13 +12,6 @@
 #include <linux/sizes.h>
 #include <asm/pci_dma.h>
 
-/*
- * Physically contiguous memory regions can be mapped with 4 KiB alignment,
- * we allow all page sizes that are an order of 4KiB (no special large page
- * support so far).
- */
-#define S390_IOMMU_PGSIZES	(~0xFFFUL)
-
 static const struct iommu_ops s390_iommu_ops;
 
 struct s390_domain {
@@ -363,7 +356,7 @@ static const struct iommu_ops s390_iommu_ops = {
 	.probe_device = s390_iommu_probe_device,
 	.release_device = s390_iommu_release_device,
 	.device_group = generic_device_group,
-	.pgsize_bitmap = S390_IOMMU_PGSIZES,
+	.pgsize_bitmap = SZ_4K,
 	.get_resv_regions = s390_iommu_get_resv_regions,
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= s390_iommu_attach_device,
-- 
2.34.1

[PATCH v8 6/6] iommu/s390: Implement map_pages()/unmap_pages() instead of map()/unmap()

[Niklas Schnelle]

While s390-iommu currently implements the map_page()/unmap_page()
operations which only map/unmap a single page at a time the internal
s390_iommu_update_trans() API already supports mapping/unmapping a range
of pages at once. Take advantage of this by implementing the
map_pages()/unmap_pages() operations instead thus allowing users of the
IOMMU drivers to map multiple pages in a single call followed by
a single I/O TLB flush if needed.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
v7->v8:
- Added Jason's R-b

 drivers/iommu/s390-iommu.c | 48 +++++++++++++++++++++++++-------------
 1 file changed, 32 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 104dfbec1037..7fb512bece9a 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -196,20 +196,15 @@ static void s390_iommu_release_device(struct device *dev)
 
 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 				   phys_addr_t pa, dma_addr_t dma_addr,
-				   size_t size, int flags)
+				   unsigned long nr_pages, int flags)
 {
 	phys_addr_t page_addr = pa & PAGE_MASK;
 	dma_addr_t start_dma_addr = dma_addr;
-	unsigned long irq_flags, nr_pages, i;
+	unsigned long irq_flags, i;
 	struct zpci_dev *zdev;
 	unsigned long *entry;
 	int rc = 0;
 
-	if (dma_addr < s390_domain->domain.geometry.aperture_start ||
-	    (dma_addr + size - 1) > s390_domain->domain.geometry.aperture_end)
-		return -EINVAL;
-
-	nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	if (!nr_pages)
 		return 0;
 
@@ -252,11 +247,24 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
 	return rc;
 }
 
-static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
-			  phys_addr_t paddr, size_t size, int prot, gfp_t gfp)
+static int s390_iommu_map_pages(struct iommu_domain *domain,
+				unsigned long iova, phys_addr_t paddr,
+				size_t pgsize, size_t pgcount,
+				int prot, gfp_t gfp, size_t *mapped)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	int flags = ZPCI_PTE_VALID, rc = 0;
+	size_t size = pgcount << __ffs(pgsize);
+
+	if (pgsize != SZ_4K)
+		return -EINVAL;
+
+	if (iova < s390_domain->domain.geometry.aperture_start ||
+	    (iova + size - 1) > s390_domain->domain.geometry.aperture_end)
+		return -EINVAL;
+
+	if (!IS_ALIGNED(iova | paddr, pgsize))
+		return -EINVAL;
 
 	if (!(prot & IOMMU_READ))
 		return -EINVAL;
@@ -265,7 +273,9 @@ static int s390_iommu_map(struct iommu_domain *domain, unsigned long iova,
 		flags |= ZPCI_TABLE_PROTECTED;
 
 	rc = s390_iommu_update_trans(s390_domain, paddr, iova,
-				     size, flags);
+				     pgcount, flags);
+	if (!rc)
+		*mapped = size;
 
 	return rc;
 }
@@ -301,21 +311,27 @@ static phys_addr_t s390_iommu_iova_to_phys(struct iommu_domain *domain,
 	return phys;
 }
 
-static size_t s390_iommu_unmap(struct iommu_domain *domain,
-			       unsigned long iova, size_t size,
-			       struct iommu_iotlb_gather *gather)
+static size_t s390_iommu_unmap_pages(struct iommu_domain *domain,
+				     unsigned long iova,
+				     size_t pgsize, size_t pgcount,
+				     struct iommu_iotlb_gather *gather)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
+	size_t size = pgcount << __ffs(pgsize);
 	int flags = ZPCI_PTE_INVALID;
 	phys_addr_t paddr;
 	int rc;
 
+	if (WARN_ON(iova < s390_domain->domain.geometry.aperture_start ||
+	    (iova + size - 1) > s390_domain->domain.geometry.aperture_end))
+		return 0;
+
 	paddr = s390_iommu_iova_to_phys(domain, iova);
 	if (!paddr)
 		return 0;
 
 	rc = s390_iommu_update_trans(s390_domain, paddr, iova,
-				     size, flags);
+				     pgcount, flags);
 	if (rc)
 		return 0;
 
@@ -361,8 +377,8 @@ static const struct iommu_ops s390_iommu_ops = {
 	.default_domain_ops = &(const struct iommu_domain_ops) {
 		.attach_dev	= s390_iommu_attach_device,
 		.detach_dev	= s390_iommu_detach_device,
-		.map		= s390_iommu_map,
-		.unmap		= s390_iommu_unmap,
+		.map_pages	= s390_iommu_map_pages,
+		.unmap_pages	= s390_iommu_unmap_pages,
 		.iova_to_phys	= s390_iommu_iova_to_phys,
 		.free		= s390_domain_free,
 	}
-- 
2.34.1

Re: [PATCH v8 0/6] iommu/s390: Fixes related to attach and aperture handling

[Joerg Roedel]

On Tue, Oct 25, 2022 at 01:56:51PM +0200, Niklas Schnelle wrote:
> Niklas Schnelle (6):
>   iommu/s390: Fix duplicate domain attachments
>   iommu/s390: Get rid of s390_domain_device
>   iommu/s390: Fix potential s390_domain aperture shrinking
>   iommu/s390: Fix incorrect aperture check
>   iommu/s390: Fix incorrect pgsize_bitmap
>   iommu/s390: Implement map_pages()/unmap_pages() instead of
>     map()/unmap()

Applied, thanks.