[PATCH v13 0/6] iommu/dma: s390 DMA API conversion and optimized IOTLB flushing

[PATCH v13 0/6] iommu/dma: s390 DMA API conversion and optimized IOTLB flushing

[Niklas Schnelle]

Hi All,

This patch series converts s390's PCI support from its platform specific DMA
API implementation in arch/s390/pci/pci_dma.c to the common DMA IOMMU layer.
The conversion itself is done in patches 3-4 with patch 2 providing the final
necessary IOMMU driver improvement to handle s390's special IOTLB flush
out-of-resource indication in virtualized environments. The conversion
itself only touches the s390 IOMMU driver and s390 arch code moving over
remaining functions from the s390 DMA API implementation. No changes to
common code are necessary.

After patch 4 the basic conversion is done and on our partitioning
machine hypervisor LPAR performance matches the previous implementation.
When running under z/VM or KVM however, performance plummets to about
half of the existing code due to a much higher rate of IOTLB flushes for
unmapped pages. Due to the hypervisors use of IOTLB flushes to
synchronize their shadow tables these are very expensive and minimizing
them is key for regaining the performance loss.

To this end patches 5-6 add a new, single queue, IOTLB flushing scheme
as an alternative to the existing per-CPU flush queues. Introducing an
alternative scheme was suggested by Robin Murphy[1]. The single queue
mode is introduced in patch 4 together with a new .shadow_on_flush flag
bit in struct dev_iommu. This allows IOMMU drivers to indicate that
their IOTLB flushes do the extra work of shadowing. This then lets the
dma-iommu code use a single queue.

Then patch 6 enables variable queue sizes using power of 2 values and
shift/mask to keep performance as close to the fixed size queue code as
possible. A larger queue size and timeout is used by dma-iommu when
shadow_on_flush is set. This same scheme may also be used by other IOMMU
drivers with similar requirements. Particularly virtio-iommu may be
a candidate.

I tested this code on s390x with LPAR, z/VM and KVM hypervisors on an
AMD Ryzen x86 system with native IOMMU and a guest with a modified
virtio-iommu[4] that set .shadow_on_flush = true.

This code is also available in the b4/dma_iommu topic branch of my
git.kernel.org repository[3] with tags matching the version sent.

NOTE: Due to the large drop in performance I think we should not merge
the DMA API conversion (patch 4) until we have a more suited IOVA
flushing scheme with similar improvements as the proposed changes.

NOTE: With the DMA API converted mlx5_core is broken on s390x since commit
06cd555f73ca ("net/mlx5: split mlx5_cmd_init() to probe and reload
routines"). A fix for the breakage has been proposed[5].

Best regards,
Niklas

[0] https://lore.kernel.org/linux-iommu/20221109142903.4080275-1-schnelle@linux.ibm.com/
[1] https://lore.kernel.org/linux-iommu/3e402947-61f9-b7e8-1414-fde006257b6f@arm.com/
[2] https://lore.kernel.org/linux-iommu/a8e778da-7b41-a6ba-83c3-c366a426c3da@arm.com/
[3] https://git.kernel.org/pub/scm/linux/kernel/git/niks/linux.git/
[4] https://lore.kernel.org/lkml/20230726111433.1105665-1-schnelle@linux.ibm.com/
[5] https://lore.kernel.org/netdev/20230928-mlx5_init_fix-v1-1-79749d45ce60@linux.ibm.com/

---
Changes in v13:
- Rebase on iommu/core which requires removing the platform domain
  handling with.
- Moved setting iommu_dma_forcedac = true to s390_iommu_init() so it
  happens before the call to iommu_dma_set_pci_32bit_workaround()
- Link to v12: https://lore.kernel.org/r/20230825-dma_iommu-v12-0-4134455994a7@linux.ibm.com

Changes in v12:
- Rebased on v6.5-rc7
- Changed queue type flag to an enum
- Incorporated feedback from Robin Murphy
  - Set options centrally and only once in iommu_dma_init_domain() with
    new helper iommu_dma_init_options()
  - Do not reset options of failing to init FQ
  - Fixed rebase mishap that partially rolled back patch 2
  - Simplified patch 4 by simply no claiming the deferred flush
    capability for ISM
  - Inlined and removed fq_flush_percpu()
  - Changed vzalloc() to vmalloc() for queue
- Added Acked-by's from Robin Murphy
- Link to v11: https://lore.kernel.org/r/20230717-dma_iommu-v11-0-a7a0b83c355c@linux.ibm.com

Changes in v11:
- Rebased on v6.5-rc2
- Added patch to force IOMMU_DOMAIN_DMA on s390 specific ISM devices
- Dropped the patch to properly set DMA mask on ISM devices which went upstream separately.
- s390 IOMMU driver now uses IOMMU_CAP_DEFERRED_FLUSH to enable DMA-FQ
  leaving no uses of IOMMU_DOMAIN_DMA_FQ in the driver.
- Link to v10: https://lore.kernel.org/r/20230310-dma_iommu-v10-0-f1fbd8310854@linux.ibm.com

Changes in v10:
- Rebased on v6.4-rc3
- Removed the .tune_dma_iommu() op in favor of a .shadow_on_flush flag
  in struct dev_iommu which then let's the dma-iommu choose a single
  queue and larger timeouts and IOVA counts. This leaves the dma-iommu
  with full responsibility for the settings.
- The above change affects patches 5 and 6 and lead to a new subject for
  patch 6 since the flush queue size and timeout is no longer driver
  controlled
- Link to v9: https://lore.kernel.org/r/20230310-dma_iommu-v9-0-65bb8edd2beb@linux.ibm.com

Changes in v9:
- Rebased on v6.4-rc2
- Re-ordered iommu_group_store_type() to allow passing the device to
  iommu_dma_init_fq()
- Link to v8: https://lore.kernel.org/r/20230310-dma_iommu-v8-0-2347dfbed7af@linux.ibm.com

---
Niklas Schnelle (6):
      iommu: Allow .iotlb_sync_map to fail and handle s390's -ENOMEM return
      s390/pci: prepare is_passed_through() for dma-iommu
      s390/pci: Use dma-iommu layer
      iommu/s390: Disable deferred flush for ISM devices
      iommu/dma: Allow a single FQ in addition to per-CPU FQs
      iommu/dma: Use a large flush queue and timeout for shadow_on_flush

 Documentation/admin-guide/kernel-parameters.txt |   9 +-
 arch/s390/include/asm/pci.h                     |   7 -
 arch/s390/include/asm/pci_clp.h                 |   3 +
 arch/s390/include/asm/pci_dma.h                 | 119 +---
 arch/s390/pci/Makefile                          |   2 +-
 arch/s390/pci/pci.c                             |  22 +-
 arch/s390/pci/pci_bus.c                         |   5 -
 arch/s390/pci/pci_debug.c                       |  12 +-
 arch/s390/pci/pci_dma.c                         | 735 ------------------------
 arch/s390/pci/pci_event.c                       |  17 +-
 arch/s390/pci/pci_sysfs.c                       |  19 +-
 drivers/iommu/Kconfig                           |   4 +-
 drivers/iommu/amd/iommu.c                       |   5 +-
 drivers/iommu/apple-dart.c                      |   5 +-
 drivers/iommu/dma-iommu.c                       | 200 +++++--
 drivers/iommu/intel/iommu.c                     |   5 +-
 drivers/iommu/iommu.c                           |  20 +-
 drivers/iommu/msm_iommu.c                       |   5 +-
 drivers/iommu/mtk_iommu.c                       |   5 +-
 drivers/iommu/s390-iommu.c                      | 434 ++++++++++++--
 drivers/iommu/sprd-iommu.c                      |   5 +-
 drivers/iommu/sun50i-iommu.c                    |   6 +-
 include/linux/iommu.h                           |   6 +-
 23 files changed, 634 insertions(+), 1016 deletions(-)
---
base-commit: ccb76c5751634541bfd2222374f46e1dea83d525
change-id: 20230310-dma_iommu-5e048c538647

Best regards,
-- 
Niklas Schnelle
Linux on Z Development

IBM Deutschland Research & Development GmbH
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Geschäftsführung: David Faller
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[PATCH v13 1/6] iommu: Allow .iotlb_sync_map to fail and handle s390's -ENOMEM return

[Niklas Schnelle]

On s390 when using a paging hypervisor, .iotlb_sync_map is used to sync
mappings by letting the hypervisor inspect the synced IOVA range and
updating a shadow table. This however means that .iotlb_sync_map can
fail as the hypervisor may run out of resources while doing the sync.
This can be due to the hypervisor being unable to pin guest pages, due
to a limit on mapped addresses such as vfio_iommu_type1.dma_entry_limit
or lack of other resources. Either way such a failure to sync a mapping
should result in a DMA_MAPPING_ERROR.

Now especially when running with batched IOTLB flushes for unmap it may
be that some IOVAs have already been invalidated but not yet synced via
.iotlb_sync_map. Thus if the hypervisor indicates running out of
resources, first do a global flush allowing the hypervisor to free
resources associated with these mappings as well a retry creating the
new mappings and only if that also fails report this error to callers.

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Acked-by: Jernej Skrabec <jernej.skrabec@gmail.com> # sun50i
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/iommu/amd/iommu.c    |  5 +++--
 drivers/iommu/apple-dart.c   |  5 +++--
 drivers/iommu/intel/iommu.c  |  5 +++--
 drivers/iommu/iommu.c        | 20 ++++++++++++++++----
 drivers/iommu/msm_iommu.c    |  5 +++--
 drivers/iommu/mtk_iommu.c    |  5 +++--
 drivers/iommu/s390-iommu.c   | 29 +++++++++++++++++++++++------
 drivers/iommu/sprd-iommu.c   |  5 +++--
 drivers/iommu/sun50i-iommu.c |  6 ++++--
 include/linux/iommu.h        |  4 ++--
 10 files changed, 63 insertions(+), 26 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index 95bd7c25ba6f..74229b1607a1 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2233,14 +2233,15 @@ static int amd_iommu_attach_device(struct iommu_domain *dom,
 	return ret;
 }
 
-static void amd_iommu_iotlb_sync_map(struct iommu_domain *dom,
-				     unsigned long iova, size_t size)
+static int amd_iommu_iotlb_sync_map(struct iommu_domain *dom,
+				    unsigned long iova, size_t size)
 {
 	struct protection_domain *domain = to_pdomain(dom);
 	struct io_pgtable_ops *ops = &domain->iop.iop.ops;
 
 	if (ops->map_pages)
 		domain_flush_np_cache(domain, iova, size);
+	return 0;
 }
 
 static int amd_iommu_map_pages(struct iommu_domain *dom, unsigned long iova,
diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 2082081402d3..22880a42ccaa 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -506,10 +506,11 @@ static void apple_dart_iotlb_sync(struct iommu_domain *domain,
 	apple_dart_domain_flush_tlb(to_dart_domain(domain));
 }
 
-static void apple_dart_iotlb_sync_map(struct iommu_domain *domain,
-				      unsigned long iova, size_t size)
+static int apple_dart_iotlb_sync_map(struct iommu_domain *domain,
+				     unsigned long iova, size_t size)
 {
 	apple_dart_domain_flush_tlb(to_dart_domain(domain));
+	return 0;
 }
 
 static phys_addr_t apple_dart_iova_to_phys(struct iommu_domain *domain,
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 5db283c17e0d..477937513502 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4678,8 +4678,8 @@ static bool risky_device(struct pci_dev *pdev)
 	return false;
 }
 
-static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
-				       unsigned long iova, size_t size)
+static int intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
+				      unsigned long iova, size_t size)
 {
 	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
 	unsigned long pages = aligned_nrpages(iova, size);
@@ -4689,6 +4689,7 @@ static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain,
 
 	xa_for_each(&dmar_domain->iommu_array, i, info)
 		__mapping_notify_one(info->iommu, dmar_domain, pfn, pages);
+	return 0;
 }
 
 static void intel_iommu_remove_dev_pasid(struct device *dev, ioasid_t pasid)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 1ecac2b5c54f..1cc9d139c860 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2585,8 +2585,17 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova,
 		return -EINVAL;
 
 	ret = __iommu_map(domain, iova, paddr, size, prot, gfp);
-	if (ret == 0 && ops->iotlb_sync_map)
-		ops->iotlb_sync_map(domain, iova, size);
+	if (ret == 0 && ops->iotlb_sync_map) {
+		ret = ops->iotlb_sync_map(domain, iova, size);
+		if (ret)
+			goto out_err;
+	}
+
+	return ret;
+
+out_err:
+	/* undo mappings already done */
+	iommu_unmap(domain, iova, size);
 
 	return ret;
 }
@@ -2714,8 +2723,11 @@ ssize_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			sg = sg_next(sg);
 	}
 
-	if (ops->iotlb_sync_map)
-		ops->iotlb_sync_map(domain, iova, mapped);
+	if (ops->iotlb_sync_map) {
+		ret = ops->iotlb_sync_map(domain, iova, mapped);
+		if (ret)
+			goto out_err;
+	}
 	return mapped;
 
 out_err:
diff --git a/drivers/iommu/msm_iommu.c b/drivers/iommu/msm_iommu.c
index a163cee0b724..f86af9815d6f 100644
--- a/drivers/iommu/msm_iommu.c
+++ b/drivers/iommu/msm_iommu.c
@@ -498,12 +498,13 @@ static int msm_iommu_map(struct iommu_domain *domain, unsigned long iova,
 	return ret;
 }
 
-static void msm_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
-			       size_t size)
+static int msm_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
+			      size_t size)
 {
 	struct msm_priv *priv = to_msm_priv(domain);
 
 	__flush_iotlb_range(iova, size, SZ_4K, false, priv);
+	return 0;
 }
 
 static size_t msm_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
index 19ef50221c93..2d8e95246781 100644
--- a/drivers/iommu/mtk_iommu.c
+++ b/drivers/iommu/mtk_iommu.c
@@ -837,12 +837,13 @@ static void mtk_iommu_iotlb_sync(struct iommu_domain *domain,
 	mtk_iommu_tlb_flush_range_sync(gather->start, length, dom->bank);
 }
 
-static void mtk_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
-			       size_t size)
+static int mtk_iommu_sync_map(struct iommu_domain *domain, unsigned long iova,
+			      size_t size)
 {
 	struct mtk_iommu_domain *dom = to_mtk_domain(domain);
 
 	mtk_iommu_tlb_flush_range_sync(iova, size, dom->bank);
+	return 0;
 }
 
 static phys_addr_t mtk_iommu_iova_to_phys(struct iommu_domain *domain,
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 5695ad71d60e..560d0957f9be 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -219,6 +219,12 @@ static void s390_iommu_release_device(struct device *dev)
 		__s390_iommu_detach_device(zdev);
 }
 
+static int zpci_refresh_all(struct zpci_dev *zdev)
+{
+	return zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
+				  zdev->end_dma - zdev->start_dma + 1);
+}
+
 static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
@@ -226,8 +232,7 @@ static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
-		zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
-				   zdev->end_dma - zdev->start_dma + 1);
+		zpci_refresh_all(zdev);
 	}
 	rcu_read_unlock();
 }
@@ -251,20 +256,32 @@ static void s390_iommu_iotlb_sync(struct iommu_domain *domain,
 	rcu_read_unlock();
 }
 
-static void s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
-				      unsigned long iova, size_t size)
+static int s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
+				     unsigned long iova, size_t size)
 {
 	struct s390_domain *s390_domain = to_s390_domain(domain);
 	struct zpci_dev *zdev;
+	int ret = 0;
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
 		if (!zdev->tlb_refresh)
 			continue;
-		zpci_refresh_trans((u64)zdev->fh << 32,
-				   iova, size);
+		ret = zpci_refresh_trans((u64)zdev->fh << 32,
+					 iova, size);
+		/*
+		 * let the hypervisor discover invalidated entries
+		 * allowing it to free IOVAs and unpin pages
+		 */
+		if (ret == -ENOMEM) {
+			ret = zpci_refresh_all(zdev);
+			if (ret)
+				break;
+		}
 	}
 	rcu_read_unlock();
+
+	return ret;
 }
 
 static int s390_iommu_validate_trans(struct s390_domain *s390_domain,
diff --git a/drivers/iommu/sprd-iommu.c b/drivers/iommu/sprd-iommu.c
index 9c33ea6903f6..2eb9fb46703b 100644
--- a/drivers/iommu/sprd-iommu.c
+++ b/drivers/iommu/sprd-iommu.c
@@ -341,8 +341,8 @@ static size_t sprd_iommu_unmap(struct iommu_domain *domain, unsigned long iova,
 	return size;
 }
 
-static void sprd_iommu_sync_map(struct iommu_domain *domain,
-				unsigned long iova, size_t size)
+static int sprd_iommu_sync_map(struct iommu_domain *domain,
+			       unsigned long iova, size_t size)
 {
 	struct sprd_iommu_domain *dom = to_sprd_domain(domain);
 	unsigned int reg;
@@ -354,6 +354,7 @@ static void sprd_iommu_sync_map(struct iommu_domain *domain,
 
 	/* clear IOMMU TLB buffer after page table updated */
 	sprd_iommu_write(dom->sdev, reg, 0xffffffff);
+	return 0;
 }
 
 static void sprd_iommu_sync(struct iommu_domain *domain,
diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
index 3c834854eda1..41484a5a399b 100644
--- a/drivers/iommu/sun50i-iommu.c
+++ b/drivers/iommu/sun50i-iommu.c
@@ -401,8 +401,8 @@ static void sun50i_iommu_flush_iotlb_all(struct iommu_domain *domain)
 	spin_unlock_irqrestore(&iommu->iommu_lock, flags);
 }
 
-static void sun50i_iommu_iotlb_sync_map(struct iommu_domain *domain,
-					unsigned long iova, size_t size)
+static int sun50i_iommu_iotlb_sync_map(struct iommu_domain *domain,
+				       unsigned long iova, size_t size)
 {
 	struct sun50i_iommu_domain *sun50i_domain = to_sun50i_domain(domain);
 	struct sun50i_iommu *iommu = sun50i_domain->iommu;
@@ -411,6 +411,8 @@ static void sun50i_iommu_iotlb_sync_map(struct iommu_domain *domain,
 	spin_lock_irqsave(&iommu->iommu_lock, flags);
 	sun50i_iommu_zap_range(iommu, iova, size);
 	spin_unlock_irqrestore(&iommu->iommu_lock, flags);
+
+	return 0;
 }
 
 static void sun50i_iommu_iotlb_sync(struct iommu_domain *domain,
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 64bd20142cbe..1eb638752781 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -350,8 +350,8 @@ struct iommu_domain_ops {
 			      struct iommu_iotlb_gather *iotlb_gather);
 
 	void (*flush_iotlb_all)(struct iommu_domain *domain);
-	void (*iotlb_sync_map)(struct iommu_domain *domain, unsigned long iova,
-			       size_t size);
+	int (*iotlb_sync_map)(struct iommu_domain *domain, unsigned long iova,
+			      size_t size);
 	void (*iotlb_sync)(struct iommu_domain *domain,
 			   struct iommu_iotlb_gather *iotlb_gather);
 

-- 
2.39.2

[PATCH v13 2/6] s390/pci: prepare is_passed_through() for dma-iommu

[Niklas Schnelle]

With the IOMMU always controlled through the IOMMU driver testing for
zdev->s390_domain is not a valid indication of the device being
passed-through. Instead test if zdev->kzdev is set.

Reviewed-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 arch/s390/pci/pci_event.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index b9324ca2eb94..4ef5a6a1d618 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -59,9 +59,16 @@ static inline bool ers_result_indicates_abort(pci_ers_result_t ers_res)
 	}
 }
 
-static bool is_passed_through(struct zpci_dev *zdev)
+static bool is_passed_through(struct pci_dev *pdev)
 {
-	return zdev->s390_domain;
+	struct zpci_dev *zdev = to_zpci(pdev);
+	bool ret;
+
+	mutex_lock(&zdev->kzdev_lock);
+	ret = !!zdev->kzdev;
+	mutex_unlock(&zdev->kzdev_lock);
+
+	return ret;
 }
 
 static bool is_driver_supported(struct pci_driver *driver)
@@ -176,7 +183,7 @@ static pci_ers_result_t zpci_event_attempt_error_recovery(struct pci_dev *pdev)
 	}
 	pdev->error_state = pci_channel_io_frozen;
 
-	if (is_passed_through(to_zpci(pdev))) {
+	if (is_passed_through(pdev)) {
 		pr_info("%s: Cannot be recovered in the host because it is a pass-through device\n",
 			pci_name(pdev));
 		goto out_unlock;
@@ -239,7 +246,7 @@ static void zpci_event_io_failure(struct pci_dev *pdev, pci_channel_state_t es)
 	 * we will inject the error event and let the guest recover the device
 	 * itself.
 	 */
-	if (is_passed_through(to_zpci(pdev)))
+	if (is_passed_through(pdev))
 		goto out;
 	driver = to_pci_driver(pdev->dev.driver);
 	if (driver && driver->err_handler && driver->err_handler->error_detected)

-- 
2.39.2

[PATCH v13 3/6] s390/pci: Use dma-iommu layer

[Niklas Schnelle]

While s390 already has a standard IOMMU driver and previous changes have
added I/O TLB flushing operations this driver is currently only used for
user-space PCI access such as vfio-pci. For the DMA API s390 instead
utilizes its own implementation in arch/s390/pci/pci_dma.c which drives
the same hardware and shares some code but requires a complex and
fragile hand over between DMA API and IOMMU API use of a device and
despite code sharing still leads to significant duplication and
maintenance effort. Let's utilize the common code DMAP API
implementation from drivers/iommu/dma-iommu.c instead allowing us to
get rid of arch/s390/pci/pci_dma.c.

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 Documentation/admin-guide/kernel-parameters.txt |   9 +-
 arch/s390/include/asm/pci.h                     |   7 -
 arch/s390/include/asm/pci_clp.h                 |   3 +
 arch/s390/include/asm/pci_dma.h                 | 119 +---
 arch/s390/pci/Makefile                          |   2 +-
 arch/s390/pci/pci.c                             |  22 +-
 arch/s390/pci/pci_bus.c                         |   5 -
 arch/s390/pci/pci_debug.c                       |  12 +-
 arch/s390/pci/pci_dma.c                         | 735 ------------------------
 arch/s390/pci/pci_event.c                       |   2 -
 arch/s390/pci/pci_sysfs.c                       |  19 +-
 drivers/iommu/Kconfig                           |   4 +-
 drivers/iommu/s390-iommu.c                      | 400 +++++++++++--
 13 files changed, 401 insertions(+), 938 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 0a1731a0f0ef..14f56c448edc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2220,7 +2220,7 @@
 			  forcing Dual Address Cycle for PCI cards supporting
 			  greater than 32-bit addressing.
 
-	iommu.strict=	[ARM64, X86] Configure TLB invalidation behaviour
+	iommu.strict=	[ARM64, X86, S390] Configure TLB invalidation behaviour
 			Format: { "0" | "1" }
 			0 - Lazy mode.
 			  Request that DMA unmap operations use deferred
@@ -5611,9 +5611,10 @@
 	s390_iommu=	[HW,S390]
 			Set s390 IOTLB flushing mode
 		strict
-			With strict flushing every unmap operation will result in
-			an IOTLB flush. Default is lazy flushing before reuse,
-			which is faster.
+			With strict flushing every unmap operation will result
+			in an IOTLB flush. Default is lazy flushing before
+			reuse, which is faster. Deprecated, equivalent to
+			iommu.strict=1.
 
 	s390_iommu_aperture=	[KNL,S390]
 			Specifies the size of the per device DMA address space
diff --git a/arch/s390/include/asm/pci.h b/arch/s390/include/asm/pci.h
index b248694e0024..3f74f1cf37df 100644
--- a/arch/s390/include/asm/pci.h
+++ b/arch/s390/include/asm/pci.h
@@ -159,13 +159,6 @@ struct zpci_dev {
 	unsigned long	*dma_table;
 	int		tlb_refresh;
 
-	spinlock_t	iommu_bitmap_lock;
-	unsigned long	*iommu_bitmap;
-	unsigned long	*lazy_bitmap;
-	unsigned long	iommu_size;
-	unsigned long	iommu_pages;
-	unsigned int	next_bit;
-
 	struct iommu_device iommu_dev;  /* IOMMU core handle */
 
 	char res_name[16];
diff --git a/arch/s390/include/asm/pci_clp.h b/arch/s390/include/asm/pci_clp.h
index d6189ed14f84..f0c677ddd270 100644
--- a/arch/s390/include/asm/pci_clp.h
+++ b/arch/s390/include/asm/pci_clp.h
@@ -50,6 +50,9 @@ struct clp_fh_list_entry {
 #define CLP_UTIL_STR_LEN	64
 #define CLP_PFIP_NR_SEGMENTS	4
 
+/* PCI function type numbers */
+#define PCI_FUNC_TYPE_ISM	0x5	/* ISM device */
+
 extern bool zpci_unique_uid;
 
 struct clp_rsp_slpc_pci {
diff --git a/arch/s390/include/asm/pci_dma.h b/arch/s390/include/asm/pci_dma.h
index 7119c04c51c5..42d7cc4262ca 100644
--- a/arch/s390/include/asm/pci_dma.h
+++ b/arch/s390/include/asm/pci_dma.h
@@ -82,117 +82,16 @@ enum zpci_ioat_dtype {
 #define ZPCI_TABLE_VALID_MASK		0x20
 #define ZPCI_TABLE_PROT_MASK		0x200
 
-static inline unsigned int calc_rtx(dma_addr_t ptr)
-{
-	return ((unsigned long) ptr >> ZPCI_RT_SHIFT) & ZPCI_INDEX_MASK;
-}
+struct zpci_iommu_ctrs {
+	atomic64_t		mapped_pages;
+	atomic64_t		unmapped_pages;
+	atomic64_t		global_rpcits;
+	atomic64_t		sync_map_rpcits;
+	atomic64_t		sync_rpcits;
+};
 
-static inline unsigned int calc_sx(dma_addr_t ptr)
-{
-	return ((unsigned long) ptr >> ZPCI_ST_SHIFT) & ZPCI_INDEX_MASK;
-}
-
-static inline unsigned int calc_px(dma_addr_t ptr)
-{
-	return ((unsigned long) ptr >> PAGE_SHIFT) & ZPCI_PT_MASK;
-}
-
-static inline void set_pt_pfaa(unsigned long *entry, phys_addr_t pfaa)
-{
-	*entry &= ZPCI_PTE_FLAG_MASK;
-	*entry |= (pfaa & ZPCI_PTE_ADDR_MASK);
-}
-
-static inline void set_rt_sto(unsigned long *entry, phys_addr_t sto)
-{
-	*entry &= ZPCI_RTE_FLAG_MASK;
-	*entry |= (sto & ZPCI_RTE_ADDR_MASK);
-	*entry |= ZPCI_TABLE_TYPE_RTX;
-}
-
-static inline void set_st_pto(unsigned long *entry, phys_addr_t pto)
-{
-	*entry &= ZPCI_STE_FLAG_MASK;
-	*entry |= (pto & ZPCI_STE_ADDR_MASK);
-	*entry |= ZPCI_TABLE_TYPE_SX;
-}
-
-static inline void validate_rt_entry(unsigned long *entry)
-{
-	*entry &= ~ZPCI_TABLE_VALID_MASK;
-	*entry &= ~ZPCI_TABLE_OFFSET_MASK;
-	*entry |= ZPCI_TABLE_VALID;
-	*entry |= ZPCI_TABLE_LEN_RTX;
-}
-
-static inline void validate_st_entry(unsigned long *entry)
-{
-	*entry &= ~ZPCI_TABLE_VALID_MASK;
-	*entry |= ZPCI_TABLE_VALID;
-}
-
-static inline void invalidate_pt_entry(unsigned long *entry)
-{
-	WARN_ON_ONCE((*entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_INVALID);
-	*entry &= ~ZPCI_PTE_VALID_MASK;
-	*entry |= ZPCI_PTE_INVALID;
-}
-
-static inline void validate_pt_entry(unsigned long *entry)
-{
-	WARN_ON_ONCE((*entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID);
-	*entry &= ~ZPCI_PTE_VALID_MASK;
-	*entry |= ZPCI_PTE_VALID;
-}
-
-static inline void entry_set_protected(unsigned long *entry)
-{
-	*entry &= ~ZPCI_TABLE_PROT_MASK;
-	*entry |= ZPCI_TABLE_PROTECTED;
-}
-
-static inline void entry_clr_protected(unsigned long *entry)
-{
-	*entry &= ~ZPCI_TABLE_PROT_MASK;
-	*entry |= ZPCI_TABLE_UNPROTECTED;
-}
-
-static inline int reg_entry_isvalid(unsigned long entry)
-{
-	return (entry & ZPCI_TABLE_VALID_MASK) == ZPCI_TABLE_VALID;
-}
-
-static inline int pt_entry_isvalid(unsigned long entry)
-{
-	return (entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID;
-}
-
-static inline unsigned long *get_rt_sto(unsigned long entry)
-{
-	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_RTX)
-		return phys_to_virt(entry & ZPCI_RTE_ADDR_MASK);
-	else
-		return NULL;
-
-}
-
-static inline unsigned long *get_st_pto(unsigned long entry)
-{
-	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_SX)
-		return phys_to_virt(entry & ZPCI_STE_ADDR_MASK);
-	else
-		return NULL;
-}
-
-/* Prototypes */
-void dma_free_seg_table(unsigned long);
-unsigned long *dma_alloc_cpu_table(gfp_t gfp);
-void dma_cleanup_tables(unsigned long *);
-unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr,
-				  gfp_t gfp);
-void dma_update_cpu_trans(unsigned long *entry, phys_addr_t page_addr, int flags);
-
-extern const struct dma_map_ops s390_pci_dma_ops;
+struct zpci_dev;
 
+struct zpci_iommu_ctrs *zpci_get_iommu_ctrs(struct zpci_dev *zdev);
 
 #endif
diff --git a/arch/s390/pci/Makefile b/arch/s390/pci/Makefile
index 5ae31ca9dd44..0547a10406e7 100644
--- a/arch/s390/pci/Makefile
+++ b/arch/s390/pci/Makefile
@@ -3,7 +3,7 @@
 # Makefile for the s390 PCI subsystem.
 #
 
-obj-$(CONFIG_PCI)	+= pci.o pci_irq.o pci_dma.o pci_clp.o pci_sysfs.o \
+obj-$(CONFIG_PCI)	+= pci.o pci_irq.o pci_clp.o pci_sysfs.o \
 			   pci_event.o pci_debug.o pci_insn.o pci_mmio.o \
 			   pci_bus.o pci_kvm_hook.o
 obj-$(CONFIG_PCI_IOV)	+= pci_iov.o
diff --git a/arch/s390/pci/pci.c b/arch/s390/pci/pci.c
index d34d5813d006..563cb72d9ed0 100644
--- a/arch/s390/pci/pci.c
+++ b/arch/s390/pci/pci.c
@@ -124,7 +124,11 @@ int zpci_register_ioat(struct zpci_dev *zdev, u8 dmaas,
 
 	WARN_ON_ONCE(iota & 0x3fff);
 	fib.pba = base;
-	fib.pal = limit;
+	/* 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.gd = zdev->gisa;
 	cc = zpci_mod_fc(req, &fib, status);
@@ -582,7 +586,6 @@ int pcibios_device_add(struct pci_dev *pdev)
 		pdev->no_vf_scan = 1;
 
 	pdev->dev.groups = zpci_attr_groups;
-	pdev->dev.dma_ops = &s390_pci_dma_ops;
 	zpci_map_resources(pdev);
 
 	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
@@ -756,8 +759,6 @@ int zpci_hot_reset_device(struct zpci_dev *zdev)
 	if (zdev->dma_table)
 		rc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 					virt_to_phys(zdev->dma_table), &status);
-	else
-		rc = zpci_dma_init_device(zdev);
 	if (rc) {
 		zpci_disable_device(zdev);
 		return rc;
@@ -865,11 +866,6 @@ int zpci_deconfigure_device(struct zpci_dev *zdev)
 	if (zdev->zbus->bus)
 		zpci_bus_remove_device(zdev, false);
 
-	if (zdev->dma_table) {
-		rc = zpci_dma_exit_device(zdev);
-		if (rc)
-			return rc;
-	}
 	if (zdev_enabled(zdev)) {
 		rc = zpci_disable_device(zdev);
 		if (rc)
@@ -918,8 +914,6 @@ void zpci_release_device(struct kref *kref)
 	if (zdev->zbus->bus)
 		zpci_bus_remove_device(zdev, false);
 
-	if (zdev->dma_table)
-		zpci_dma_exit_device(zdev);
 	if (zdev_enabled(zdev))
 		zpci_disable_device(zdev);
 
@@ -1109,10 +1103,6 @@ static int __init pci_base_init(void)
 	if (rc)
 		goto out_irq;
 
-	rc = zpci_dma_init();
-	if (rc)
-		goto out_dma;
-
 	rc = clp_scan_pci_devices();
 	if (rc)
 		goto out_find;
@@ -1122,8 +1112,6 @@ static int __init pci_base_init(void)
 	return 0;
 
 out_find:
-	zpci_dma_exit();
-out_dma:
 	zpci_irq_exit();
 out_irq:
 	zpci_mem_exit();
diff --git a/arch/s390/pci/pci_bus.c b/arch/s390/pci/pci_bus.c
index 32245b970a0c..daa5d7450c7d 100644
--- a/arch/s390/pci/pci_bus.c
+++ b/arch/s390/pci/pci_bus.c
@@ -47,11 +47,6 @@ static int zpci_bus_prepare_device(struct zpci_dev *zdev)
 		rc = zpci_enable_device(zdev);
 		if (rc)
 			return rc;
-		rc = zpci_dma_init_device(zdev);
-		if (rc) {
-			zpci_disable_device(zdev);
-			return rc;
-		}
 	}
 
 	if (!zdev->has_resources) {
diff --git a/arch/s390/pci/pci_debug.c b/arch/s390/pci/pci_debug.c
index ca6bd98eec13..6dde2263c79d 100644
--- a/arch/s390/pci/pci_debug.c
+++ b/arch/s390/pci/pci_debug.c
@@ -53,9 +53,11 @@ static char *pci_fmt3_names[] = {
 };
 
 static char *pci_sw_names[] = {
-	"Allocated pages",
 	"Mapped pages",
 	"Unmapped pages",
+	"Global RPCITs",
+	"Sync Map RPCITs",
+	"Sync RPCITs",
 };
 
 static void pci_fmb_show(struct seq_file *m, char *name[], int length,
@@ -69,10 +71,14 @@ static void pci_fmb_show(struct seq_file *m, char *name[], int length,
 
 static void pci_sw_counter_show(struct seq_file *m)
 {
-	struct zpci_dev *zdev = m->private;
-	atomic64_t *counter = &zdev->allocated_pages;
+	struct zpci_iommu_ctrs  *ctrs = zpci_get_iommu_ctrs(m->private);
+	atomic64_t *counter;
 	int i;
 
+	if (!ctrs)
+		return;
+
+	counter = &ctrs->mapped_pages;
 	for (i = 0; i < ARRAY_SIZE(pci_sw_names); i++, counter++)
 		seq_printf(m, "%26s:\t%llu\n", pci_sw_names[i],
 			   atomic64_read(counter));
diff --git a/arch/s390/pci/pci_dma.c b/arch/s390/pci/pci_dma.c
deleted file mode 100644
index 2d9b01d7ca4c..000000000000
--- a/arch/s390/pci/pci_dma.c
+++ /dev/null
@@ -1,735 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-/*
- * Copyright IBM Corp. 2012
- *
- * Author(s):
- *   Jan Glauber <jang@linux.vnet.ibm.com>
- */
-
-#include <linux/kernel.h>
-#include <linux/slab.h>
-#include <linux/export.h>
-#include <linux/iommu-helper.h>
-#include <linux/dma-map-ops.h>
-#include <linux/vmalloc.h>
-#include <linux/pci.h>
-#include <asm/pci_dma.h>
-
-static struct kmem_cache *dma_region_table_cache;
-static struct kmem_cache *dma_page_table_cache;
-static int s390_iommu_strict;
-static u64 s390_iommu_aperture;
-static u32 s390_iommu_aperture_factor = 1;
-
-static int zpci_refresh_global(struct zpci_dev *zdev)
-{
-	return zpci_refresh_trans((u64) zdev->fh << 32, zdev->start_dma,
-				  zdev->iommu_pages * PAGE_SIZE);
-}
-
-unsigned long *dma_alloc_cpu_table(gfp_t gfp)
-{
-	unsigned long *table, *entry;
-
-	table = kmem_cache_alloc(dma_region_table_cache, gfp);
-	if (!table)
-		return NULL;
-
-	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
-		*entry = ZPCI_TABLE_INVALID;
-	return table;
-}
-
-static void dma_free_cpu_table(void *table)
-{
-	kmem_cache_free(dma_region_table_cache, table);
-}
-
-static unsigned long *dma_alloc_page_table(gfp_t gfp)
-{
-	unsigned long *table, *entry;
-
-	table = kmem_cache_alloc(dma_page_table_cache, gfp);
-	if (!table)
-		return NULL;
-
-	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
-		*entry = ZPCI_PTE_INVALID;
-	return table;
-}
-
-static void dma_free_page_table(void *table)
-{
-	kmem_cache_free(dma_page_table_cache, table);
-}
-
-static unsigned long *dma_get_seg_table_origin(unsigned long *rtep, gfp_t gfp)
-{
-	unsigned long old_rte, rte;
-	unsigned long *sto;
-
-	rte = READ_ONCE(*rtep);
-	if (reg_entry_isvalid(rte)) {
-		sto = get_rt_sto(rte);
-	} else {
-		sto = dma_alloc_cpu_table(gfp);
-		if (!sto)
-			return NULL;
-
-		set_rt_sto(&rte, virt_to_phys(sto));
-		validate_rt_entry(&rte);
-		entry_clr_protected(&rte);
-
-		old_rte = cmpxchg(rtep, ZPCI_TABLE_INVALID, rte);
-		if (old_rte != ZPCI_TABLE_INVALID) {
-			/* Somone else was faster, use theirs */
-			dma_free_cpu_table(sto);
-			sto = get_rt_sto(old_rte);
-		}
-	}
-	return sto;
-}
-
-static unsigned long *dma_get_page_table_origin(unsigned long *step, gfp_t gfp)
-{
-	unsigned long old_ste, ste;
-	unsigned long *pto;
-
-	ste = READ_ONCE(*step);
-	if (reg_entry_isvalid(ste)) {
-		pto = get_st_pto(ste);
-	} else {
-		pto = dma_alloc_page_table(gfp);
-		if (!pto)
-			return NULL;
-		set_st_pto(&ste, virt_to_phys(pto));
-		validate_st_entry(&ste);
-		entry_clr_protected(&ste);
-
-		old_ste = cmpxchg(step, ZPCI_TABLE_INVALID, ste);
-		if (old_ste != ZPCI_TABLE_INVALID) {
-			/* Somone else was faster, use theirs */
-			dma_free_page_table(pto);
-			pto = get_st_pto(old_ste);
-		}
-	}
-	return pto;
-}
-
-unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr,
-				  gfp_t gfp)
-{
-	unsigned long *sto, *pto;
-	unsigned int rtx, sx, px;
-
-	rtx = calc_rtx(dma_addr);
-	sto = dma_get_seg_table_origin(&rto[rtx], gfp);
-	if (!sto)
-		return NULL;
-
-	sx = calc_sx(dma_addr);
-	pto = dma_get_page_table_origin(&sto[sx], gfp);
-	if (!pto)
-		return NULL;
-
-	px = calc_px(dma_addr);
-	return &pto[px];
-}
-
-void dma_update_cpu_trans(unsigned long *ptep, phys_addr_t page_addr, int flags)
-{
-	unsigned long pte;
-
-	pte = READ_ONCE(*ptep);
-	if (flags & ZPCI_PTE_INVALID) {
-		invalidate_pt_entry(&pte);
-	} else {
-		set_pt_pfaa(&pte, page_addr);
-		validate_pt_entry(&pte);
-	}
-
-	if (flags & ZPCI_TABLE_PROTECTED)
-		entry_set_protected(&pte);
-	else
-		entry_clr_protected(&pte);
-
-	xchg(ptep, pte);
-}
-
-static int __dma_update_trans(struct zpci_dev *zdev, phys_addr_t pa,
-			      dma_addr_t dma_addr, size_t size, int flags)
-{
-	unsigned int nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	phys_addr_t page_addr = (pa & PAGE_MASK);
-	unsigned long *entry;
-	int i, rc = 0;
-
-	if (!nr_pages)
-		return -EINVAL;
-
-	if (!zdev->dma_table)
-		return -EINVAL;
-
-	for (i = 0; i < nr_pages; i++) {
-		entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr,
-					   GFP_ATOMIC);
-		if (!entry) {
-			rc = -ENOMEM;
-			goto undo_cpu_trans;
-		}
-		dma_update_cpu_trans(entry, page_addr, flags);
-		page_addr += PAGE_SIZE;
-		dma_addr += PAGE_SIZE;
-	}
-
-undo_cpu_trans:
-	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
-		flags = ZPCI_PTE_INVALID;
-		while (i-- > 0) {
-			page_addr -= PAGE_SIZE;
-			dma_addr -= PAGE_SIZE;
-			entry = dma_walk_cpu_trans(zdev->dma_table, dma_addr,
-						   GFP_ATOMIC);
-			if (!entry)
-				break;
-			dma_update_cpu_trans(entry, page_addr, flags);
-		}
-	}
-	return rc;
-}
-
-static int __dma_purge_tlb(struct zpci_dev *zdev, dma_addr_t dma_addr,
-			   size_t size, int flags)
-{
-	unsigned long irqflags;
-	int ret;
-
-	/*
-	 * With zdev->tlb_refresh == 0, rpcit is not required to establish new
-	 * translations when previously invalid translation-table entries are
-	 * validated. With lazy unmap, rpcit is skipped for previously valid
-	 * entries, but a global rpcit is then required before any address can
-	 * be re-used, i.e. after each iommu bitmap wrap-around.
-	 */
-	if ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID) {
-		if (!zdev->tlb_refresh)
-			return 0;
-	} else {
-		if (!s390_iommu_strict)
-			return 0;
-	}
-
-	ret = zpci_refresh_trans((u64) zdev->fh << 32, dma_addr,
-				 PAGE_ALIGN(size));
-	if (ret == -ENOMEM && !s390_iommu_strict) {
-		/* enable the hypervisor to free some resources */
-		if (zpci_refresh_global(zdev))
-			goto out;
-
-		spin_lock_irqsave(&zdev->iommu_bitmap_lock, irqflags);
-		bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
-			      zdev->lazy_bitmap, zdev->iommu_pages);
-		bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
-		spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, irqflags);
-		ret = 0;
-	}
-out:
-	return ret;
-}
-
-static int dma_update_trans(struct zpci_dev *zdev, phys_addr_t pa,
-			    dma_addr_t dma_addr, size_t size, int flags)
-{
-	int rc;
-
-	rc = __dma_update_trans(zdev, pa, dma_addr, size, flags);
-	if (rc)
-		return rc;
-
-	rc = __dma_purge_tlb(zdev, dma_addr, size, flags);
-	if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID))
-		__dma_update_trans(zdev, pa, dma_addr, size, ZPCI_PTE_INVALID);
-
-	return rc;
-}
-
-void dma_free_seg_table(unsigned long entry)
-{
-	unsigned long *sto = get_rt_sto(entry);
-	int sx;
-
-	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
-		if (reg_entry_isvalid(sto[sx]))
-			dma_free_page_table(get_st_pto(sto[sx]));
-
-	dma_free_cpu_table(sto);
-}
-
-void dma_cleanup_tables(unsigned long *table)
-{
-	int rtx;
-
-	if (!table)
-		return;
-
-	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
-		if (reg_entry_isvalid(table[rtx]))
-			dma_free_seg_table(table[rtx]);
-
-	dma_free_cpu_table(table);
-}
-
-static unsigned long __dma_alloc_iommu(struct device *dev,
-				       unsigned long start, int size)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-
-	return iommu_area_alloc(zdev->iommu_bitmap, zdev->iommu_pages,
-				start, size, zdev->start_dma >> PAGE_SHIFT,
-				dma_get_seg_boundary_nr_pages(dev, PAGE_SHIFT),
-				0);
-}
-
-static dma_addr_t dma_alloc_address(struct device *dev, int size)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-	unsigned long offset, flags;
-
-	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
-	offset = __dma_alloc_iommu(dev, zdev->next_bit, size);
-	if (offset == -1) {
-		if (!s390_iommu_strict) {
-			/* global flush before DMA addresses are reused */
-			if (zpci_refresh_global(zdev))
-				goto out_error;
-
-			bitmap_andnot(zdev->iommu_bitmap, zdev->iommu_bitmap,
-				      zdev->lazy_bitmap, zdev->iommu_pages);
-			bitmap_zero(zdev->lazy_bitmap, zdev->iommu_pages);
-		}
-		/* wrap-around */
-		offset = __dma_alloc_iommu(dev, 0, size);
-		if (offset == -1)
-			goto out_error;
-	}
-	zdev->next_bit = offset + size;
-	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
-
-	return zdev->start_dma + offset * PAGE_SIZE;
-
-out_error:
-	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
-	return DMA_MAPPING_ERROR;
-}
-
-static void dma_free_address(struct device *dev, dma_addr_t dma_addr, int size)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-	unsigned long flags, offset;
-
-	offset = (dma_addr - zdev->start_dma) >> PAGE_SHIFT;
-
-	spin_lock_irqsave(&zdev->iommu_bitmap_lock, flags);
-	if (!zdev->iommu_bitmap)
-		goto out;
-
-	if (s390_iommu_strict)
-		bitmap_clear(zdev->iommu_bitmap, offset, size);
-	else
-		bitmap_set(zdev->lazy_bitmap, offset, size);
-
-out:
-	spin_unlock_irqrestore(&zdev->iommu_bitmap_lock, flags);
-}
-
-static inline void zpci_err_dma(unsigned long rc, unsigned long addr)
-{
-	struct {
-		unsigned long rc;
-		unsigned long addr;
-	} __packed data = {rc, addr};
-
-	zpci_err_hex(&data, sizeof(data));
-}
-
-static dma_addr_t s390_dma_map_pages(struct device *dev, struct page *page,
-				     unsigned long offset, size_t size,
-				     enum dma_data_direction direction,
-				     unsigned long attrs)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-	unsigned long pa = page_to_phys(page) + offset;
-	int flags = ZPCI_PTE_VALID;
-	unsigned long nr_pages;
-	dma_addr_t dma_addr;
-	int ret;
-
-	/* This rounds up number of pages based on size and offset */
-	nr_pages = iommu_num_pages(pa, size, PAGE_SIZE);
-	dma_addr = dma_alloc_address(dev, nr_pages);
-	if (dma_addr == DMA_MAPPING_ERROR) {
-		ret = -ENOSPC;
-		goto out_err;
-	}
-
-	/* Use rounded up size */
-	size = nr_pages * PAGE_SIZE;
-
-	if (direction == DMA_NONE || direction == DMA_TO_DEVICE)
-		flags |= ZPCI_TABLE_PROTECTED;
-
-	ret = dma_update_trans(zdev, pa, dma_addr, size, flags);
-	if (ret)
-		goto out_free;
-
-	atomic64_add(nr_pages, &zdev->mapped_pages);
-	return dma_addr + (offset & ~PAGE_MASK);
-
-out_free:
-	dma_free_address(dev, dma_addr, nr_pages);
-out_err:
-	zpci_err("map error:\n");
-	zpci_err_dma(ret, pa);
-	return DMA_MAPPING_ERROR;
-}
-
-static void s390_dma_unmap_pages(struct device *dev, dma_addr_t dma_addr,
-				 size_t size, enum dma_data_direction direction,
-				 unsigned long attrs)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-	int npages, ret;
-
-	npages = iommu_num_pages(dma_addr, size, PAGE_SIZE);
-	dma_addr = dma_addr & PAGE_MASK;
-	ret = dma_update_trans(zdev, 0, dma_addr, npages * PAGE_SIZE,
-			       ZPCI_PTE_INVALID);
-	if (ret) {
-		zpci_err("unmap error:\n");
-		zpci_err_dma(ret, dma_addr);
-		return;
-	}
-
-	atomic64_add(npages, &zdev->unmapped_pages);
-	dma_free_address(dev, dma_addr, npages);
-}
-
-static void *s390_dma_alloc(struct device *dev, size_t size,
-			    dma_addr_t *dma_handle, gfp_t flag,
-			    unsigned long attrs)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-	struct page *page;
-	phys_addr_t pa;
-	dma_addr_t map;
-
-	size = PAGE_ALIGN(size);
-	page = alloc_pages(flag | __GFP_ZERO, get_order(size));
-	if (!page)
-		return NULL;
-
-	pa = page_to_phys(page);
-	map = s390_dma_map_pages(dev, page, 0, size, DMA_BIDIRECTIONAL, 0);
-	if (dma_mapping_error(dev, map)) {
-		__free_pages(page, get_order(size));
-		return NULL;
-	}
-
-	atomic64_add(size / PAGE_SIZE, &zdev->allocated_pages);
-	if (dma_handle)
-		*dma_handle = map;
-	return phys_to_virt(pa);
-}
-
-static void s390_dma_free(struct device *dev, size_t size,
-			  void *vaddr, dma_addr_t dma_handle,
-			  unsigned long attrs)
-{
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-
-	size = PAGE_ALIGN(size);
-	atomic64_sub(size / PAGE_SIZE, &zdev->allocated_pages);
-	s390_dma_unmap_pages(dev, dma_handle, size, DMA_BIDIRECTIONAL, 0);
-	free_pages((unsigned long)vaddr, get_order(size));
-}
-
-/* Map a segment into a contiguous dma address area */
-static int __s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
-			     size_t size, dma_addr_t *handle,
-			     enum dma_data_direction dir)
-{
-	unsigned long nr_pages = PAGE_ALIGN(size) >> PAGE_SHIFT;
-	struct zpci_dev *zdev = to_zpci(to_pci_dev(dev));
-	dma_addr_t dma_addr_base, dma_addr;
-	int flags = ZPCI_PTE_VALID;
-	struct scatterlist *s;
-	phys_addr_t pa = 0;
-	int ret;
-
-	dma_addr_base = dma_alloc_address(dev, nr_pages);
-	if (dma_addr_base == DMA_MAPPING_ERROR)
-		return -ENOMEM;
-
-	dma_addr = dma_addr_base;
-	if (dir == DMA_NONE || dir == DMA_TO_DEVICE)
-		flags |= ZPCI_TABLE_PROTECTED;
-
-	for (s = sg; dma_addr < dma_addr_base + size; s = sg_next(s)) {
-		pa = page_to_phys(sg_page(s));
-		ret = __dma_update_trans(zdev, pa, dma_addr,
-					 s->offset + s->length, flags);
-		if (ret)
-			goto unmap;
-
-		dma_addr += s->offset + s->length;
-	}
-	ret = __dma_purge_tlb(zdev, dma_addr_base, size, flags);
-	if (ret)
-		goto unmap;
-
-	*handle = dma_addr_base;
-	atomic64_add(nr_pages, &zdev->mapped_pages);
-
-	return ret;
-
-unmap:
-	dma_update_trans(zdev, 0, dma_addr_base, dma_addr - dma_addr_base,
-			 ZPCI_PTE_INVALID);
-	dma_free_address(dev, dma_addr_base, nr_pages);
-	zpci_err("map error:\n");
-	zpci_err_dma(ret, pa);
-	return ret;
-}
-
-static int s390_dma_map_sg(struct device *dev, struct scatterlist *sg,
-			   int nr_elements, enum dma_data_direction dir,
-			   unsigned long attrs)
-{
-	struct scatterlist *s = sg, *start = sg, *dma = sg;
-	unsigned int max = dma_get_max_seg_size(dev);
-	unsigned int size = s->offset + s->length;
-	unsigned int offset = s->offset;
-	int count = 0, i, ret;
-
-	for (i = 1; i < nr_elements; i++) {
-		s = sg_next(s);
-
-		s->dma_length = 0;
-
-		if (s->offset || (size & ~PAGE_MASK) ||
-		    size + s->length > max) {
-			ret = __s390_dma_map_sg(dev, start, size,
-						&dma->dma_address, dir);
-			if (ret)
-				goto unmap;
-
-			dma->dma_address += offset;
-			dma->dma_length = size - offset;
-
-			size = offset = s->offset;
-			start = s;
-			dma = sg_next(dma);
-			count++;
-		}
-		size += s->length;
-	}
-	ret = __s390_dma_map_sg(dev, start, size, &dma->dma_address, dir);
-	if (ret)
-		goto unmap;
-
-	dma->dma_address += offset;
-	dma->dma_length = size - offset;
-
-	return count + 1;
-unmap:
-	for_each_sg(sg, s, count, i)
-		s390_dma_unmap_pages(dev, sg_dma_address(s), sg_dma_len(s),
-				     dir, attrs);
-
-	return ret;
-}
-
-static void s390_dma_unmap_sg(struct device *dev, struct scatterlist *sg,
-			      int nr_elements, enum dma_data_direction dir,
-			      unsigned long attrs)
-{
-	struct scatterlist *s;
-	int i;
-
-	for_each_sg(sg, s, nr_elements, i) {
-		if (s->dma_length)
-			s390_dma_unmap_pages(dev, s->dma_address, s->dma_length,
-					     dir, attrs);
-		s->dma_address = 0;
-		s->dma_length = 0;
-	}
-}
-	
-int zpci_dma_init_device(struct zpci_dev *zdev)
-{
-	u8 status;
-	int rc;
-
-	/*
-	 * At this point, if the device is part of an IOMMU domain, this would
-	 * be a strong hint towards a bug in the IOMMU API (common) code and/or
-	 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
-	 */
-	WARN_ON(zdev->s390_domain);
-
-	spin_lock_init(&zdev->iommu_bitmap_lock);
-
-	zdev->dma_table = dma_alloc_cpu_table(GFP_KERNEL);
-	if (!zdev->dma_table) {
-		rc = -ENOMEM;
-		goto out;
-	}
-
-	/*
-	 * Restrict the iommu bitmap size to the minimum of the following:
-	 * - s390_iommu_aperture which defaults to high_memory
-	 * - 3-level pagetable address limit minus start_dma offset
-	 * - DMA address range allowed by the hardware (clp query pci fn)
-	 *
-	 * Also set zdev->end_dma to the actual end address of the usable
-	 * range, instead of the theoretical maximum as reported by hardware.
-	 *
-	 * This limits the number of concurrently usable DMA mappings since
-	 * for each DMA mapped memory address we need a DMA address including
-	 * extra DMA addresses for multiple mappings of the same memory address.
-	 */
-	zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
-	zdev->iommu_size = min3(s390_iommu_aperture,
-				ZPCI_TABLE_SIZE_RT - zdev->start_dma,
-				zdev->end_dma - zdev->start_dma + 1);
-	zdev->end_dma = zdev->start_dma + zdev->iommu_size - 1;
-	zdev->iommu_pages = zdev->iommu_size >> PAGE_SHIFT;
-	zdev->iommu_bitmap = vzalloc(zdev->iommu_pages / 8);
-	if (!zdev->iommu_bitmap) {
-		rc = -ENOMEM;
-		goto free_dma_table;
-	}
-	if (!s390_iommu_strict) {
-		zdev->lazy_bitmap = vzalloc(zdev->iommu_pages / 8);
-		if (!zdev->lazy_bitmap) {
-			rc = -ENOMEM;
-			goto free_bitmap;
-		}
-
-	}
-	if (zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
-			       virt_to_phys(zdev->dma_table), &status)) {
-		rc = -EIO;
-		goto free_bitmap;
-	}
-
-	return 0;
-free_bitmap:
-	vfree(zdev->iommu_bitmap);
-	zdev->iommu_bitmap = NULL;
-	vfree(zdev->lazy_bitmap);
-	zdev->lazy_bitmap = NULL;
-free_dma_table:
-	dma_free_cpu_table(zdev->dma_table);
-	zdev->dma_table = NULL;
-out:
-	return rc;
-}
-
-int zpci_dma_exit_device(struct zpci_dev *zdev)
-{
-	int cc = 0;
-
-	/*
-	 * At this point, if the device is part of an IOMMU domain, this would
-	 * be a strong hint towards a bug in the IOMMU API (common) code and/or
-	 * simultaneous access via IOMMU and DMA API. So let's issue a warning.
-	 */
-	WARN_ON(zdev->s390_domain);
-	if (zdev_enabled(zdev))
-		cc = zpci_unregister_ioat(zdev, 0);
-	/*
-	 * cc == 3 indicates the function is gone already. This can happen
-	 * if the function was deconfigured/disabled suddenly and we have not
-	 * received a new handle yet.
-	 */
-	if (cc && cc != 3)
-		return -EIO;
-
-	dma_cleanup_tables(zdev->dma_table);
-	zdev->dma_table = NULL;
-	vfree(zdev->iommu_bitmap);
-	zdev->iommu_bitmap = NULL;
-	vfree(zdev->lazy_bitmap);
-	zdev->lazy_bitmap = NULL;
-	zdev->next_bit = 0;
-	return 0;
-}
-
-static int __init dma_alloc_cpu_table_caches(void)
-{
-	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
-					ZPCI_TABLE_SIZE, ZPCI_TABLE_ALIGN,
-					0, NULL);
-	if (!dma_region_table_cache)
-		return -ENOMEM;
-
-	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
-					ZPCI_PT_SIZE, ZPCI_PT_ALIGN,
-					0, NULL);
-	if (!dma_page_table_cache) {
-		kmem_cache_destroy(dma_region_table_cache);
-		return -ENOMEM;
-	}
-	return 0;
-}
-
-int __init zpci_dma_init(void)
-{
-	s390_iommu_aperture = (u64)virt_to_phys(high_memory);
-	if (!s390_iommu_aperture_factor)
-		s390_iommu_aperture = ULONG_MAX;
-	else
-		s390_iommu_aperture *= s390_iommu_aperture_factor;
-
-	return dma_alloc_cpu_table_caches();
-}
-
-void zpci_dma_exit(void)
-{
-	kmem_cache_destroy(dma_page_table_cache);
-	kmem_cache_destroy(dma_region_table_cache);
-}
-
-const struct dma_map_ops s390_pci_dma_ops = {
-	.alloc		= s390_dma_alloc,
-	.free		= s390_dma_free,
-	.map_sg		= s390_dma_map_sg,
-	.unmap_sg	= s390_dma_unmap_sg,
-	.map_page	= s390_dma_map_pages,
-	.unmap_page	= s390_dma_unmap_pages,
-	.mmap		= dma_common_mmap,
-	.get_sgtable	= dma_common_get_sgtable,
-	.alloc_pages	= dma_common_alloc_pages,
-	.free_pages	= dma_common_free_pages,
-	/* dma_supported is unconditionally true without a callback */
-};
-EXPORT_SYMBOL_GPL(s390_pci_dma_ops);
-
-static int __init s390_iommu_setup(char *str)
-{
-	if (!strcmp(str, "strict"))
-		s390_iommu_strict = 1;
-	return 1;
-}
-
-__setup("s390_iommu=", s390_iommu_setup);
-
-static int __init s390_iommu_aperture_setup(char *str)
-{
-	if (kstrtou32(str, 10, &s390_iommu_aperture_factor))
-		s390_iommu_aperture_factor = 1;
-	return 1;
-}
-
-__setup("s390_iommu_aperture=", s390_iommu_aperture_setup);
diff --git a/arch/s390/pci/pci_event.c b/arch/s390/pci/pci_event.c
index 4ef5a6a1d618..4d9773ef9e0a 100644
--- a/arch/s390/pci/pci_event.c
+++ b/arch/s390/pci/pci_event.c
@@ -313,8 +313,6 @@ static void zpci_event_hard_deconfigured(struct zpci_dev *zdev, u32 fh)
 	/* Even though the device is already gone we still
 	 * need to free zPCI resources as part of the disable.
 	 */
-	if (zdev->dma_table)
-		zpci_dma_exit_device(zdev);
 	if (zdev_enabled(zdev))
 		zpci_disable_device(zdev);
 	zdev->state = ZPCI_FN_STATE_STANDBY;
diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c
index cae280e5c047..8a7abac51816 100644
--- a/arch/s390/pci/pci_sysfs.c
+++ b/arch/s390/pci/pci_sysfs.c
@@ -56,6 +56,7 @@ static ssize_t recover_store(struct device *dev, struct device_attribute *attr,
 	struct pci_dev *pdev = to_pci_dev(dev);
 	struct zpci_dev *zdev = to_zpci(pdev);
 	int ret = 0;
+	u8 status;
 
 	/* Can't use device_remove_self() here as that would lead us to lock
 	 * the pci_rescan_remove_lock while holding the device' kernfs lock.
@@ -82,12 +83,6 @@ static ssize_t recover_store(struct device *dev, struct device_attribute *attr,
 	pci_lock_rescan_remove();
 	if (pci_dev_is_added(pdev)) {
 		pci_stop_and_remove_bus_device(pdev);
-		if (zdev->dma_table) {
-			ret = zpci_dma_exit_device(zdev);
-			if (ret)
-				goto out;
-		}
-
 		if (zdev_enabled(zdev)) {
 			ret = zpci_disable_device(zdev);
 			/*
@@ -105,14 +100,16 @@ static ssize_t recover_store(struct device *dev, struct device_attribute *attr,
 		ret = zpci_enable_device(zdev);
 		if (ret)
 			goto out;
-		ret = zpci_dma_init_device(zdev);
-		if (ret) {
-			zpci_disable_device(zdev);
-			goto out;
+
+		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);
 		}
-		pci_rescan_bus(zdev->zbus->bus);
 	}
 out:
+	pci_rescan_bus(zdev->zbus->bus);
 	pci_unlock_rescan_remove();
 	if (kn)
 		sysfs_unbreak_active_protection(kn);
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index cd6727898b11..3199fd54b462 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -91,7 +91,7 @@ config IOMMU_DEBUGFS
 choice
 	prompt "IOMMU default domain type"
 	depends on IOMMU_API
-	default IOMMU_DEFAULT_DMA_LAZY if X86 || IA64
+	default IOMMU_DEFAULT_DMA_LAZY if X86 || IA64 || S390
 	default IOMMU_DEFAULT_DMA_STRICT
 	help
 	  Choose the type of IOMMU domain used to manage DMA API usage by
@@ -146,7 +146,7 @@ config OF_IOMMU
 
 # IOMMU-agnostic DMA-mapping layer
 config IOMMU_DMA
-	def_bool ARM64 || IA64 || X86
+	def_bool ARM64 || IA64 || X86 || S390
 	select DMA_OPS
 	select IOMMU_API
 	select IOMMU_IOVA
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 560d0957f9be..bb9e48c82644 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -14,16 +14,300 @@
 #include <linux/rcupdate.h>
 #include <asm/pci_dma.h>
 
+#include "dma-iommu.h"
+
 static const struct iommu_ops s390_iommu_ops;
 
+static struct kmem_cache *dma_region_table_cache;
+static struct kmem_cache *dma_page_table_cache;
+
+static u64 s390_iommu_aperture;
+static u32 s390_iommu_aperture_factor = 1;
+
 struct s390_domain {
 	struct iommu_domain	domain;
 	struct list_head	devices;
+	struct zpci_iommu_ctrs	ctrs;
 	unsigned long		*dma_table;
 	spinlock_t		list_lock;
 	struct rcu_head		rcu;
 };
 
+static inline unsigned int calc_rtx(dma_addr_t ptr)
+{
+	return ((unsigned long)ptr >> ZPCI_RT_SHIFT) & ZPCI_INDEX_MASK;
+}
+
+static inline unsigned int calc_sx(dma_addr_t ptr)
+{
+	return ((unsigned long)ptr >> ZPCI_ST_SHIFT) & ZPCI_INDEX_MASK;
+}
+
+static inline unsigned int calc_px(dma_addr_t ptr)
+{
+	return ((unsigned long)ptr >> PAGE_SHIFT) & ZPCI_PT_MASK;
+}
+
+static inline void set_pt_pfaa(unsigned long *entry, phys_addr_t pfaa)
+{
+	*entry &= ZPCI_PTE_FLAG_MASK;
+	*entry |= (pfaa & ZPCI_PTE_ADDR_MASK);
+}
+
+static inline void set_rt_sto(unsigned long *entry, phys_addr_t sto)
+{
+	*entry &= ZPCI_RTE_FLAG_MASK;
+	*entry |= (sto & ZPCI_RTE_ADDR_MASK);
+	*entry |= ZPCI_TABLE_TYPE_RTX;
+}
+
+static inline void set_st_pto(unsigned long *entry, phys_addr_t pto)
+{
+	*entry &= ZPCI_STE_FLAG_MASK;
+	*entry |= (pto & ZPCI_STE_ADDR_MASK);
+	*entry |= ZPCI_TABLE_TYPE_SX;
+}
+
+static inline void validate_rt_entry(unsigned long *entry)
+{
+	*entry &= ~ZPCI_TABLE_VALID_MASK;
+	*entry &= ~ZPCI_TABLE_OFFSET_MASK;
+	*entry |= ZPCI_TABLE_VALID;
+	*entry |= ZPCI_TABLE_LEN_RTX;
+}
+
+static inline void validate_st_entry(unsigned long *entry)
+{
+	*entry &= ~ZPCI_TABLE_VALID_MASK;
+	*entry |= ZPCI_TABLE_VALID;
+}
+
+static inline void invalidate_pt_entry(unsigned long *entry)
+{
+	WARN_ON_ONCE((*entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_INVALID);
+	*entry &= ~ZPCI_PTE_VALID_MASK;
+	*entry |= ZPCI_PTE_INVALID;
+}
+
+static inline void validate_pt_entry(unsigned long *entry)
+{
+	WARN_ON_ONCE((*entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID);
+	*entry &= ~ZPCI_PTE_VALID_MASK;
+	*entry |= ZPCI_PTE_VALID;
+}
+
+static inline void entry_set_protected(unsigned long *entry)
+{
+	*entry &= ~ZPCI_TABLE_PROT_MASK;
+	*entry |= ZPCI_TABLE_PROTECTED;
+}
+
+static inline void entry_clr_protected(unsigned long *entry)
+{
+	*entry &= ~ZPCI_TABLE_PROT_MASK;
+	*entry |= ZPCI_TABLE_UNPROTECTED;
+}
+
+static inline int reg_entry_isvalid(unsigned long entry)
+{
+	return (entry & ZPCI_TABLE_VALID_MASK) == ZPCI_TABLE_VALID;
+}
+
+static inline int pt_entry_isvalid(unsigned long entry)
+{
+	return (entry & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID;
+}
+
+static inline unsigned long *get_rt_sto(unsigned long entry)
+{
+	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_RTX)
+		return phys_to_virt(entry & ZPCI_RTE_ADDR_MASK);
+	else
+		return NULL;
+}
+
+static inline unsigned long *get_st_pto(unsigned long entry)
+{
+	if ((entry & ZPCI_TABLE_TYPE_MASK) == ZPCI_TABLE_TYPE_SX)
+		return phys_to_virt(entry & ZPCI_STE_ADDR_MASK);
+	else
+		return NULL;
+}
+
+static int __init dma_alloc_cpu_table_caches(void)
+{
+	dma_region_table_cache = kmem_cache_create("PCI_DMA_region_tables",
+						   ZPCI_TABLE_SIZE,
+						   ZPCI_TABLE_ALIGN,
+						   0, NULL);
+	if (!dma_region_table_cache)
+		return -ENOMEM;
+
+	dma_page_table_cache = kmem_cache_create("PCI_DMA_page_tables",
+						 ZPCI_PT_SIZE,
+						 ZPCI_PT_ALIGN,
+						 0, NULL);
+	if (!dma_page_table_cache) {
+		kmem_cache_destroy(dma_region_table_cache);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static unsigned long *dma_alloc_cpu_table(gfp_t gfp)
+{
+	unsigned long *table, *entry;
+
+	table = kmem_cache_alloc(dma_region_table_cache, gfp);
+	if (!table)
+		return NULL;
+
+	for (entry = table; entry < table + ZPCI_TABLE_ENTRIES; entry++)
+		*entry = ZPCI_TABLE_INVALID;
+	return table;
+}
+
+static void dma_free_cpu_table(void *table)
+{
+	kmem_cache_free(dma_region_table_cache, table);
+}
+
+static void dma_free_page_table(void *table)
+{
+	kmem_cache_free(dma_page_table_cache, table);
+}
+
+static void dma_free_seg_table(unsigned long entry)
+{
+	unsigned long *sto = get_rt_sto(entry);
+	int sx;
+
+	for (sx = 0; sx < ZPCI_TABLE_ENTRIES; sx++)
+		if (reg_entry_isvalid(sto[sx]))
+			dma_free_page_table(get_st_pto(sto[sx]));
+
+	dma_free_cpu_table(sto);
+}
+
+static void dma_cleanup_tables(unsigned long *table)
+{
+	int rtx;
+
+	if (!table)
+		return;
+
+	for (rtx = 0; rtx < ZPCI_TABLE_ENTRIES; rtx++)
+		if (reg_entry_isvalid(table[rtx]))
+			dma_free_seg_table(table[rtx]);
+
+	dma_free_cpu_table(table);
+}
+
+static unsigned long *dma_alloc_page_table(gfp_t gfp)
+{
+	unsigned long *table, *entry;
+
+	table = kmem_cache_alloc(dma_page_table_cache, gfp);
+	if (!table)
+		return NULL;
+
+	for (entry = table; entry < table + ZPCI_PT_ENTRIES; entry++)
+		*entry = ZPCI_PTE_INVALID;
+	return table;
+}
+
+static unsigned long *dma_get_seg_table_origin(unsigned long *rtep, gfp_t gfp)
+{
+	unsigned long old_rte, rte;
+	unsigned long *sto;
+
+	rte = READ_ONCE(*rtep);
+	if (reg_entry_isvalid(rte)) {
+		sto = get_rt_sto(rte);
+	} else {
+		sto = dma_alloc_cpu_table(gfp);
+		if (!sto)
+			return NULL;
+
+		set_rt_sto(&rte, virt_to_phys(sto));
+		validate_rt_entry(&rte);
+		entry_clr_protected(&rte);
+
+		old_rte = cmpxchg(rtep, ZPCI_TABLE_INVALID, rte);
+		if (old_rte != ZPCI_TABLE_INVALID) {
+			/* Somone else was faster, use theirs */
+			dma_free_cpu_table(sto);
+			sto = get_rt_sto(old_rte);
+		}
+	}
+	return sto;
+}
+
+static unsigned long *dma_get_page_table_origin(unsigned long *step, gfp_t gfp)
+{
+	unsigned long old_ste, ste;
+	unsigned long *pto;
+
+	ste = READ_ONCE(*step);
+	if (reg_entry_isvalid(ste)) {
+		pto = get_st_pto(ste);
+	} else {
+		pto = dma_alloc_page_table(gfp);
+		if (!pto)
+			return NULL;
+		set_st_pto(&ste, virt_to_phys(pto));
+		validate_st_entry(&ste);
+		entry_clr_protected(&ste);
+
+		old_ste = cmpxchg(step, ZPCI_TABLE_INVALID, ste);
+		if (old_ste != ZPCI_TABLE_INVALID) {
+			/* Somone else was faster, use theirs */
+			dma_free_page_table(pto);
+			pto = get_st_pto(old_ste);
+		}
+	}
+	return pto;
+}
+
+static unsigned long *dma_walk_cpu_trans(unsigned long *rto, dma_addr_t dma_addr, gfp_t gfp)
+{
+	unsigned long *sto, *pto;
+	unsigned int rtx, sx, px;
+
+	rtx = calc_rtx(dma_addr);
+	sto = dma_get_seg_table_origin(&rto[rtx], gfp);
+	if (!sto)
+		return NULL;
+
+	sx = calc_sx(dma_addr);
+	pto = dma_get_page_table_origin(&sto[sx], gfp);
+	if (!pto)
+		return NULL;
+
+	px = calc_px(dma_addr);
+	return &pto[px];
+}
+
+static void dma_update_cpu_trans(unsigned long *ptep, phys_addr_t page_addr, int flags)
+{
+	unsigned long pte;
+
+	pte = READ_ONCE(*ptep);
+	if (flags & ZPCI_PTE_INVALID) {
+		invalidate_pt_entry(&pte);
+	} else {
+		set_pt_pfaa(&pte, page_addr);
+		validate_pt_entry(&pte);
+	}
+
+	if (flags & ZPCI_TABLE_PROTECTED)
+		entry_set_protected(&pte);
+	else
+		entry_clr_protected(&pte);
+
+	xchg(ptep, pte);
+}
+
 static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
 {
 	return container_of(dom, struct s390_domain, domain);
@@ -34,6 +318,8 @@ static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap)
 	switch (cap) {
 	case IOMMU_CAP_CACHE_COHERENCY:
 		return true;
+	case IOMMU_CAP_DEFERRED_FLUSH:
+		return true;
 	default:
 		return false;
 	}
@@ -81,14 +367,13 @@ static void s390_domain_free(struct iommu_domain *domain)
 	call_rcu(&s390_domain->rcu, s390_iommu_rcu_free_domain);
 }
 
-static void __s390_iommu_detach_device(struct zpci_dev *zdev)
+static void s390_iommu_detach_device(struct iommu_domain *domain,
+				     struct device *dev)
 {
-	struct s390_domain *s390_domain = zdev->s390_domain;
+	struct s390_domain *s390_domain = to_s390_domain(domain);
+	struct zpci_dev *zdev = to_zpci_dev(dev);
 	unsigned long flags;
 
-	if (!s390_domain)
-		return;
-
 	spin_lock_irqsave(&s390_domain->list_lock, flags);
 	list_del_rcu(&zdev->iommu_list);
 	spin_unlock_irqrestore(&s390_domain->list_lock, flags);
@@ -115,9 +400,7 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 		return -EINVAL;
 
 	if (zdev->s390_domain)
-		__s390_iommu_detach_device(zdev);
-	else if (zdev->dma_table)
-		zpci_dma_exit_device(zdev);
+		s390_iommu_detach_device(&zdev->s390_domain->domain, dev);
 
 	cc = zpci_register_ioat(zdev, 0, zdev->start_dma, zdev->end_dma,
 				virt_to_phys(s390_domain->dma_table), &status);
@@ -127,7 +410,6 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	 */
 	if (cc && status != ZPCI_PCI_ST_FUNC_NOT_AVAIL)
 		return -EIO;
-	zdev->dma_table = s390_domain->dma_table;
 
 	zdev->dma_table = s390_domain->dma_table;
 	zdev->s390_domain = s390_domain;
@@ -139,31 +421,6 @@ static int s390_iommu_attach_device(struct iommu_domain *domain,
 	return 0;
 }
 
-/*
- * Switch control over the IOMMU to S390's internal dma_api ops
- */
-static int s390_iommu_platform_attach(struct iommu_domain *platform_domain,
-				      struct device *dev)
-{
-	struct zpci_dev *zdev = to_zpci_dev(dev);
-
-	if (!zdev->s390_domain)
-		return 0;
-
-	__s390_iommu_detach_device(zdev);
-	zpci_dma_init_device(zdev);
-	return 0;
-}
-
-static struct iommu_domain_ops s390_iommu_platform_ops = {
-	.attach_dev = s390_iommu_platform_attach,
-};
-
-static struct iommu_domain s390_iommu_platform_domain = {
-	.type = IOMMU_DOMAIN_PLATFORM,
-	.ops = &s390_iommu_platform_ops,
-};
-
 static void s390_iommu_get_resv_regions(struct device *dev,
 					struct list_head *list)
 {
@@ -216,7 +473,7 @@ static void s390_iommu_release_device(struct device *dev)
 	 * to the device, but keep it attached to other devices in the group.
 	 */
 	if (zdev)
-		__s390_iommu_detach_device(zdev);
+		s390_iommu_detach_device(&zdev->s390_domain->domain, dev);
 }
 
 static int zpci_refresh_all(struct zpci_dev *zdev)
@@ -232,6 +489,7 @@ static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
+		atomic64_inc(&s390_domain->ctrs.global_rpcits);
 		zpci_refresh_all(zdev);
 	}
 	rcu_read_unlock();
@@ -250,6 +508,7 @@ static void s390_iommu_iotlb_sync(struct iommu_domain *domain,
 
 	rcu_read_lock();
 	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
+		atomic64_inc(&s390_domain->ctrs.sync_rpcits);
 		zpci_refresh_trans((u64)zdev->fh << 32, gather->start,
 				   size);
 	}
@@ -267,6 +526,7 @@ static int s390_iommu_iotlb_sync_map(struct iommu_domain *domain,
 	list_for_each_entry_rcu(zdev, &s390_domain->devices, iommu_list) {
 		if (!zdev->tlb_refresh)
 			continue;
+		atomic64_inc(&s390_domain->ctrs.sync_map_rpcits);
 		ret = zpci_refresh_trans((u64)zdev->fh << 32,
 					 iova, size);
 		/*
@@ -361,16 +621,15 @@ static int s390_iommu_map_pages(struct iommu_domain *domain,
 	if (!IS_ALIGNED(iova | paddr, pgsize))
 		return -EINVAL;
 
-	if (!(prot & IOMMU_READ))
-		return -EINVAL;
-
 	if (!(prot & IOMMU_WRITE))
 		flags |= ZPCI_TABLE_PROTECTED;
 
 	rc = s390_iommu_validate_trans(s390_domain, paddr, iova,
-				       pgcount, flags, gfp);
-	if (!rc)
+				     pgcount, flags, gfp);
+	if (!rc) {
 		*mapped = size;
+		atomic64_add(pgcount, &s390_domain->ctrs.mapped_pages);
+	}
 
 	return rc;
 }
@@ -426,12 +685,26 @@ static size_t s390_iommu_unmap_pages(struct iommu_domain *domain,
 		return 0;
 
 	iommu_iotlb_gather_add_range(gather, iova, size);
+	atomic64_add(pgcount, &s390_domain->ctrs.unmapped_pages);
 
 	return size;
 }
 
+static void s390_iommu_probe_finalize(struct device *dev)
+{
+	iommu_setup_dma_ops(dev, 0, U64_MAX);
+}
+
+struct zpci_iommu_ctrs *zpci_get_iommu_ctrs(struct zpci_dev *zdev)
+{
+	if (!zdev || !zdev->s390_domain)
+		return NULL;
+	return &zdev->s390_domain->ctrs;
+}
+
 int zpci_init_iommu(struct zpci_dev *zdev)
 {
+	u64 aperture_size;
 	int rc = 0;
 
 	rc = iommu_device_sysfs_add(&zdev->iommu_dev, NULL, NULL,
@@ -443,6 +716,12 @@ int zpci_init_iommu(struct zpci_dev *zdev)
 	if (rc)
 		goto out_sysfs;
 
+	zdev->start_dma = PAGE_ALIGN(zdev->start_dma);
+	aperture_size = min3(s390_iommu_aperture,
+			     ZPCI_TABLE_SIZE_RT - zdev->start_dma,
+			     zdev->end_dma - zdev->start_dma + 1);
+	zdev->end_dma = zdev->start_dma + aperture_size - 1;
+
 	return 0;
 
 out_sysfs:
@@ -458,11 +737,50 @@ void zpci_destroy_iommu(struct zpci_dev *zdev)
 	iommu_device_sysfs_remove(&zdev->iommu_dev);
 }
 
+static int __init s390_iommu_setup(char *str)
+{
+	if (!strcmp(str, "strict")) {
+		pr_warn("s390_iommu=strict deprecated; use iommu.strict=1 instead\n");
+		iommu_set_dma_strict();
+	}
+	return 1;
+}
+
+__setup("s390_iommu=", s390_iommu_setup);
+
+static int __init s390_iommu_aperture_setup(char *str)
+{
+	if (kstrtou32(str, 10, &s390_iommu_aperture_factor))
+		s390_iommu_aperture_factor = 1;
+	return 1;
+}
+
+__setup("s390_iommu_aperture=", s390_iommu_aperture_setup);
+
+static int __init s390_iommu_init(void)
+{
+	int rc;
+
+	iommu_dma_forcedac = true;
+	s390_iommu_aperture = (u64)virt_to_phys(high_memory);
+	if (!s390_iommu_aperture_factor)
+		s390_iommu_aperture = ULONG_MAX;
+	else
+		s390_iommu_aperture *= s390_iommu_aperture_factor;
+
+	rc = dma_alloc_cpu_table_caches();
+	if (rc)
+		return rc;
+
+	return rc;
+}
+subsys_initcall(s390_iommu_init);
+
 static const struct iommu_ops s390_iommu_ops = {
-	.default_domain = &s390_iommu_platform_domain,
 	.capable = s390_iommu_capable,
 	.domain_alloc_paging = s390_domain_alloc_paging,
 	.probe_device = s390_iommu_probe_device,
+	.probe_finalize = s390_iommu_probe_finalize,
 	.release_device = s390_iommu_release_device,
 	.device_group = generic_device_group,
 	.pgsize_bitmap = SZ_4K,

-- 
2.39.2

[PATCH v13 4/6] iommu/s390: Disable deferred flush for ISM devices

[Niklas Schnelle]

ISM devices are virtual PCI devices used for cross-LPAR communication.
Unlike real PCI devices ISM devices do not use the hardware IOMMU but
inspects IOMMU translation tables directly on IOTLB flush (s390 RPCIT
instruction).

ISM devices keep their DMA allocations static and only very rarely DMA
unmap at all. For each IOTLB flush that occurs after unmap the ISM
devices will however inspect the area of the IOVA space indicated by the
flush. This means that for the global IOTLB flushes used by the flush
queue mechanism the entire IOVA space would be inspected. In principle
this would be fine, albeit potentially unnecessarily slow, it turns out
however that ISM devices are sensitive to seeing IOVA addresses that are
currently in use in the IOVA range being flushed. Seeing such in-use
IOVA addresses will cause the ISM device to enter an error state and
become unusable.

Fix this by claiming IOMMU_CAP_DEFERRED_FLUSH only for non-ISM devices.
This makes sure IOTLB flushes only cover IOVAs that have been unmapped
and also restricts the range of the IOTLB flush potentially reducing
latency spikes.

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/iommu/s390-iommu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index bb9e48c82644..5b5ba1cd5f00 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -315,11 +315,13 @@ static struct s390_domain *to_s390_domain(struct iommu_domain *dom)
 
 static bool s390_iommu_capable(struct device *dev, enum iommu_cap cap)
 {
+	struct zpci_dev *zdev = to_zpci_dev(dev);
+
 	switch (cap) {
 	case IOMMU_CAP_CACHE_COHERENCY:
 		return true;
 	case IOMMU_CAP_DEFERRED_FLUSH:
-		return true;
+		return zdev->pft != PCI_FUNC_TYPE_ISM;
 	default:
 		return false;
 	}

-- 
2.39.2

[PATCH v13 5/6] iommu/dma: Allow a single FQ in addition to per-CPU FQs

[Niklas Schnelle]

In some virtualized environments, including s390 paged memory guests,
IOTLB flushes are used to update IOMMU shadow tables. Due to this, they
are much more expensive than in typical bare metal environments or
non-paged s390 guests. In addition they may parallelize poorly in
virtualized environments. This changes the trade off for flushing IOVAs
such that minimizing the number of IOTLB flushes trumps any benefit of
cheaper queuing operations or increased paralellism.

In this scenario per-CPU flush queues pose several problems. Firstly
per-CPU memory is often quite limited prohibiting larger queues.
Secondly collecting IOVAs per-CPU but flushing via a global timeout
reduces the number of IOVAs flushed for each timeout especially on s390
where PCI interrupts may not be bound to a specific CPU.

Let's introduce a single flush queue mode that reuses the same queue
logic but only allocates a single global queue. This mode is selected by
dma-iommu if a newly introduced .shadow_on_flush flag is set in struct
dev_iommu. As a first user the s390 IOMMU driver sets this flag during
probe_device. With the unchanged small FQ size and timeouts this setting
is worse than per-CPU queues but a follow up patch will make the FQ size
and timeout variable. Together this allows the common IOVA flushing code
to more closely resemble the global flush behavior used on s390's
previous internal DMA API implementation.

Link: https://lore.kernel.org/all/9a466109-01c5-96b0-bf03-304123f435ee@arm.com/
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> #s390
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/iommu/dma-iommu.c  | 168 ++++++++++++++++++++++++++++++++++-----------
 drivers/iommu/s390-iommu.c |   3 +
 include/linux/iommu.h      |   2 +
 3 files changed, 134 insertions(+), 39 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4b1a88f514c9..a85ff75ad531 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -43,14 +43,26 @@ enum iommu_dma_cookie_type {
 	IOMMU_DMA_MSI_COOKIE,
 };
 
+enum iommu_dma_queue_type {
+	IOMMU_DMA_OPTS_PER_CPU_QUEUE,
+	IOMMU_DMA_OPTS_SINGLE_QUEUE,
+};
+
+struct iommu_dma_options {
+	enum iommu_dma_queue_type qt;
+};
+
 struct iommu_dma_cookie {
 	enum iommu_dma_cookie_type	type;
 	union {
 		/* Full allocator for IOMMU_DMA_IOVA_COOKIE */
 		struct {
 			struct iova_domain	iovad;
-
-			struct iova_fq __percpu *fq;	/* Flush queue */
+			/* Flush queue */
+			union {
+				struct iova_fq	*single_fq;
+				struct iova_fq	__percpu *percpu_fq;
+			};
 			/* Number of TLB flushes that have been started */
 			atomic64_t		fq_flush_start_cnt;
 			/* Number of TLB flushes that have been finished */
@@ -67,6 +79,8 @@ struct iommu_dma_cookie {
 
 	/* Domain for flush queue callback; NULL if flush queue not in use */
 	struct iommu_domain		*fq_domain;
+	/* Options for dma-iommu use */
+	struct iommu_dma_options	options;
 	struct mutex			mutex;
 };
 
@@ -124,7 +138,7 @@ static inline unsigned int fq_ring_add(struct iova_fq *fq)
 	return idx;
 }
 
-static void fq_ring_free(struct iommu_dma_cookie *cookie, struct iova_fq *fq)
+static void fq_ring_free_locked(struct iommu_dma_cookie *cookie, struct iova_fq *fq)
 {
 	u64 counter = atomic64_read(&cookie->fq_flush_finish_cnt);
 	unsigned int idx;
@@ -145,6 +159,15 @@ static void fq_ring_free(struct iommu_dma_cookie *cookie, struct iova_fq *fq)
 	}
 }
 
+static void fq_ring_free(struct iommu_dma_cookie *cookie, struct iova_fq *fq)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&fq->lock, flags);
+	fq_ring_free_locked(cookie, fq);
+	spin_unlock_irqrestore(&fq->lock, flags);
+}
+
 static void fq_flush_iotlb(struct iommu_dma_cookie *cookie)
 {
 	atomic64_inc(&cookie->fq_flush_start_cnt);
@@ -160,14 +183,11 @@ static void fq_flush_timeout(struct timer_list *t)
 	atomic_set(&cookie->fq_timer_on, 0);
 	fq_flush_iotlb(cookie);
 
-	for_each_possible_cpu(cpu) {
-		unsigned long flags;
-		struct iova_fq *fq;
-
-		fq = per_cpu_ptr(cookie->fq, cpu);
-		spin_lock_irqsave(&fq->lock, flags);
-		fq_ring_free(cookie, fq);
-		spin_unlock_irqrestore(&fq->lock, flags);
+	if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE) {
+		fq_ring_free(cookie, cookie->single_fq);
+	} else {
+		for_each_possible_cpu(cpu)
+			fq_ring_free(cookie, per_cpu_ptr(cookie->percpu_fq, cpu));
 	}
 }
 
@@ -188,7 +208,11 @@ static void queue_iova(struct iommu_dma_cookie *cookie,
 	 */
 	smp_mb();
 
-	fq = raw_cpu_ptr(cookie->fq);
+	if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE)
+		fq = cookie->single_fq;
+	else
+		fq = raw_cpu_ptr(cookie->percpu_fq);
+
 	spin_lock_irqsave(&fq->lock, flags);
 
 	/*
@@ -196,11 +220,11 @@ static void queue_iova(struct iommu_dma_cookie *cookie,
 	 * flushed out on another CPU. This makes the fq_full() check below less
 	 * likely to be true.
 	 */
-	fq_ring_free(cookie, fq);
+	fq_ring_free_locked(cookie, fq);
 
 	if (fq_full(fq)) {
 		fq_flush_iotlb(cookie);
-		fq_ring_free(cookie, fq);
+		fq_ring_free_locked(cookie, fq);
 	}
 
 	idx = fq_ring_add(fq);
@@ -219,31 +243,88 @@ static void queue_iova(struct iommu_dma_cookie *cookie,
 			  jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));
 }
 
-static void iommu_dma_free_fq(struct iommu_dma_cookie *cookie)
+static void iommu_dma_free_fq_single(struct iova_fq *fq)
+{
+	int idx;
+
+	fq_ring_for_each(idx, fq)
+		put_pages_list(&fq->entries[idx].freelist);
+	vfree(fq);
+}
+
+static void iommu_dma_free_fq_percpu(struct iova_fq __percpu *percpu_fq)
 {
 	int cpu, idx;
 
-	if (!cookie->fq)
-		return;
-
-	del_timer_sync(&cookie->fq_timer);
 	/* The IOVAs will be torn down separately, so just free our queued pages */
 	for_each_possible_cpu(cpu) {
-		struct iova_fq *fq = per_cpu_ptr(cookie->fq, cpu);
+		struct iova_fq *fq = per_cpu_ptr(percpu_fq, cpu);
 
 		fq_ring_for_each(idx, fq)
 			put_pages_list(&fq->entries[idx].freelist);
 	}
 
-	free_percpu(cookie->fq);
+	free_percpu(percpu_fq);
+}
+
+static void iommu_dma_free_fq(struct iommu_dma_cookie *cookie)
+{
+	if (!cookie->fq_domain)
+		return;
+
+	del_timer_sync(&cookie->fq_timer);
+	if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE)
+		iommu_dma_free_fq_single(cookie->single_fq);
+	else
+		iommu_dma_free_fq_percpu(cookie->percpu_fq);
+}
+
+static void iommu_dma_init_one_fq(struct iova_fq *fq)
+{
+	int i;
+
+	fq->head = 0;
+	fq->tail = 0;
+
+	spin_lock_init(&fq->lock);
+
+	for (i = 0; i < IOVA_FQ_SIZE; i++)
+		INIT_LIST_HEAD(&fq->entries[i].freelist);
+}
+
+static int iommu_dma_init_fq_single(struct iommu_dma_cookie *cookie)
+{
+	struct iova_fq *queue;
+
+	queue = vmalloc(sizeof(*queue));
+	if (!queue)
+		return -ENOMEM;
+	iommu_dma_init_one_fq(queue);
+	cookie->single_fq = queue;
+
+	return 0;
+}
+
+static int iommu_dma_init_fq_percpu(struct iommu_dma_cookie *cookie)
+{
+	struct iova_fq __percpu *queue;
+	int cpu;
+
+	queue = alloc_percpu(struct iova_fq);
+	if (!queue)
+		return -ENOMEM;
+
+	for_each_possible_cpu(cpu)
+		iommu_dma_init_one_fq(per_cpu_ptr(queue, cpu));
+	cookie->percpu_fq = queue;
+	return 0;
 }
 
 /* sysfs updates are serialised by the mutex of the group owning @domain */
 int iommu_dma_init_fq(struct iommu_domain *domain)
 {
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
-	struct iova_fq __percpu *queue;
-	int i, cpu;
+	int rc;
 
 	if (cookie->fq_domain)
 		return 0;
@@ -251,26 +332,16 @@ int iommu_dma_init_fq(struct iommu_domain *domain)
 	atomic64_set(&cookie->fq_flush_start_cnt,  0);
 	atomic64_set(&cookie->fq_flush_finish_cnt, 0);
 
-	queue = alloc_percpu(struct iova_fq);
-	if (!queue) {
+	if (cookie->options.qt == IOMMU_DMA_OPTS_SINGLE_QUEUE)
+		rc = iommu_dma_init_fq_single(cookie);
+	else
+		rc = iommu_dma_init_fq_percpu(cookie);
+
+	if (rc) {
 		pr_warn("iova flush queue initialization failed\n");
 		return -ENOMEM;
 	}
 
-	for_each_possible_cpu(cpu) {
-		struct iova_fq *fq = per_cpu_ptr(queue, cpu);
-
-		fq->head = 0;
-		fq->tail = 0;
-
-		spin_lock_init(&fq->lock);
-
-		for (i = 0; i < IOVA_FQ_SIZE; i++)
-			INIT_LIST_HEAD(&fq->entries[i].freelist);
-	}
-
-	cookie->fq = queue;
-
 	timer_setup(&cookie->fq_timer, fq_flush_timeout, 0);
 	atomic_set(&cookie->fq_timer_on, 0);
 	/*
@@ -554,6 +625,23 @@ static bool dev_use_sg_swiotlb(struct device *dev, struct scatterlist *sg,
 	return false;
 }
 
+/**
+ * iommu_dma_init_options - Initialize dma-iommu options
+ * @options: The options to be initialized
+ * @dev: Device the options are set for
+ *
+ * This allows tuning dma-iommu specific to device properties
+ */
+static void iommu_dma_init_options(struct iommu_dma_options *options,
+				   struct device *dev)
+{
+	/* Shadowing IOTLB flushes do better with a single queue */
+	if (dev->iommu->shadow_on_flush)
+		options->qt = IOMMU_DMA_OPTS_SINGLE_QUEUE;
+	else
+		options->qt = IOMMU_DMA_OPTS_PER_CPU_QUEUE;
+}
+
 /**
  * iommu_dma_init_domain - Initialise a DMA mapping domain
  * @domain: IOMMU domain previously prepared by iommu_get_dma_cookie()
@@ -614,6 +702,8 @@ static int iommu_dma_init_domain(struct iommu_domain *domain, dma_addr_t base,
 	if (ret)
 		goto done_unlock;
 
+	iommu_dma_init_options(&cookie->options, dev);
+
 	/* If the FQ fails we can simply fall back to strict mode */
 	if (domain->type == IOMMU_DOMAIN_DMA_FQ &&
 	    (!device_iommu_capable(dev, IOMMU_CAP_DEFERRED_FLUSH) || iommu_dma_init_fq(domain)))
diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 5b5ba1cd5f00..9a5196f523de 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -463,6 +463,9 @@ static struct iommu_device *s390_iommu_probe_device(struct device *dev)
 	if (zdev->end_dma > ZPCI_TABLE_SIZE_RT - 1)
 		zdev->end_dma = ZPCI_TABLE_SIZE_RT - 1;
 
+	if (zdev->tlb_refresh)
+		dev->iommu->shadow_on_flush = 1;
+
 	return &zdev->iommu_dev;
 }
 
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 1eb638752781..0c4d8ae985ac 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -424,6 +424,7 @@ struct iommu_fault_param {
  * @attach_deferred: the dma domain attachment is deferred
  * @pci_32bit_workaround: Limit DMA allocations to 32-bit IOVAs
  * @require_direct: device requires IOMMU_RESV_DIRECT regions
+ * @shadow_on_flush: IOTLB flushes are used to sync shadow tables
  *
  * TODO: migrate other per device data pointers under iommu_dev_data, e.g.
  *	struct iommu_group	*iommu_group;
@@ -439,6 +440,7 @@ struct dev_iommu {
 	u32				attach_deferred:1;
 	u32				pci_32bit_workaround:1;
 	u32				require_direct:1;
+	u32				shadow_on_flush:1;
 };
 
 int iommu_device_register(struct iommu_device *iommu,

-- 
2.39.2

[PATCH v13 6/6] iommu/dma: Use a large flush queue and timeout for shadow_on_flush

[Niklas Schnelle]

Flush queues currently use a fixed compile time size of 256 entries.
This being a power of 2 allows the compiler to use shift and mask
instead of more expensive modulo operations. With per-CPU flush queues
larger queue sizes would hit per-CPU allocation limits, with a single
flush queue these limits do not apply however. Also with single queues
being particularly suitable for virtualized environments with expensive
IOTLB flushes these benefit especially from larger queues and thus fewer
flushes.

To this end re-order struct iova_fq so we can use a dynamic array and
introduce the flush queue size and timeouts as new options in the
iommu_dma_options struct. So as not to lose the shift and mask
optimization, use a power of 2 for the length and use explicit shift and
mask instead of letting the compiler optimize this.

A large queue size and 1 second timeout is then set for the shadow on
flush case set by s390 paged memory guests. This then brings performance
on par with the previous s390 specific DMA API implementation.

Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com> #s390
Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
---
 drivers/iommu/dma-iommu.c | 50 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 32 insertions(+), 18 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index a85ff75ad531..85163a83df2f 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -50,6 +50,8 @@ enum iommu_dma_queue_type {
 
 struct iommu_dma_options {
 	enum iommu_dma_queue_type qt;
+	size_t		fq_size;
+	unsigned int	fq_timeout;
 };
 
 struct iommu_dma_cookie {
@@ -98,10 +100,12 @@ static int __init iommu_dma_forcedac_setup(char *str)
 early_param("iommu.forcedac", iommu_dma_forcedac_setup);
 
 /* Number of entries per flush queue */
-#define IOVA_FQ_SIZE	256
+#define IOVA_DEFAULT_FQ_SIZE	256
+#define IOVA_SINGLE_FQ_SIZE	32768
 
 /* Timeout (in ms) after which entries are flushed from the queue */
-#define IOVA_FQ_TIMEOUT	10
+#define IOVA_DEFAULT_FQ_TIMEOUT	10
+#define IOVA_SINGLE_FQ_TIMEOUT	1000
 
 /* Flush queue entry for deferred flushing */
 struct iova_fq_entry {
@@ -113,18 +117,19 @@ struct iova_fq_entry {
 
 /* Per-CPU flush queue structure */
 struct iova_fq {
-	struct iova_fq_entry entries[IOVA_FQ_SIZE];
-	unsigned int head, tail;
 	spinlock_t lock;
+	unsigned int head, tail;
+	unsigned int mod_mask;
+	struct iova_fq_entry entries[];
 };
 
 #define fq_ring_for_each(i, fq) \
-	for ((i) = (fq)->head; (i) != (fq)->tail; (i) = ((i) + 1) % IOVA_FQ_SIZE)
+	for ((i) = (fq)->head; (i) != (fq)->tail; (i) = ((i) + 1) & (fq)->mod_mask)
 
 static inline bool fq_full(struct iova_fq *fq)
 {
 	assert_spin_locked(&fq->lock);
-	return (((fq->tail + 1) % IOVA_FQ_SIZE) == fq->head);
+	return (((fq->tail + 1) & fq->mod_mask) == fq->head);
 }
 
 static inline unsigned int fq_ring_add(struct iova_fq *fq)
@@ -133,7 +138,7 @@ static inline unsigned int fq_ring_add(struct iova_fq *fq)
 
 	assert_spin_locked(&fq->lock);
 
-	fq->tail = (idx + 1) % IOVA_FQ_SIZE;
+	fq->tail = (idx + 1) & fq->mod_mask;
 
 	return idx;
 }
@@ -155,7 +160,7 @@ static void fq_ring_free_locked(struct iommu_dma_cookie *cookie, struct iova_fq
 			       fq->entries[idx].iova_pfn,
 			       fq->entries[idx].pages);
 
-		fq->head = (fq->head + 1) % IOVA_FQ_SIZE;
+		fq->head = (fq->head + 1) & fq->mod_mask;
 	}
 }
 
@@ -240,7 +245,7 @@ static void queue_iova(struct iommu_dma_cookie *cookie,
 	if (!atomic_read(&cookie->fq_timer_on) &&
 	    !atomic_xchg(&cookie->fq_timer_on, 1))
 		mod_timer(&cookie->fq_timer,
-			  jiffies + msecs_to_jiffies(IOVA_FQ_TIMEOUT));
+			  jiffies + msecs_to_jiffies(cookie->options.fq_timeout));
 }
 
 static void iommu_dma_free_fq_single(struct iova_fq *fq)
@@ -279,27 +284,29 @@ static void iommu_dma_free_fq(struct iommu_dma_cookie *cookie)
 		iommu_dma_free_fq_percpu(cookie->percpu_fq);
 }
 
-static void iommu_dma_init_one_fq(struct iova_fq *fq)
+static void iommu_dma_init_one_fq(struct iova_fq *fq, size_t fq_size)
 {
 	int i;
 
 	fq->head = 0;
 	fq->tail = 0;
+	fq->mod_mask = fq_size - 1;
 
 	spin_lock_init(&fq->lock);
 
-	for (i = 0; i < IOVA_FQ_SIZE; i++)
+	for (i = 0; i < fq_size; i++)
 		INIT_LIST_HEAD(&fq->entries[i].freelist);
 }
 
 static int iommu_dma_init_fq_single(struct iommu_dma_cookie *cookie)
 {
+	size_t fq_size = cookie->options.fq_size;
 	struct iova_fq *queue;
 
-	queue = vmalloc(sizeof(*queue));
+	queue = vmalloc(struct_size(queue, entries, fq_size));
 	if (!queue)
 		return -ENOMEM;
-	iommu_dma_init_one_fq(queue);
+	iommu_dma_init_one_fq(queue, fq_size);
 	cookie->single_fq = queue;
 
 	return 0;
@@ -307,15 +314,17 @@ static int iommu_dma_init_fq_single(struct iommu_dma_cookie *cookie)
 
 static int iommu_dma_init_fq_percpu(struct iommu_dma_cookie *cookie)
 {
+	size_t fq_size = cookie->options.fq_size;
 	struct iova_fq __percpu *queue;
 	int cpu;
 
-	queue = alloc_percpu(struct iova_fq);
+	queue = __alloc_percpu(struct_size(queue, entries, fq_size),
+			       __alignof__(*queue));
 	if (!queue)
 		return -ENOMEM;
 
 	for_each_possible_cpu(cpu)
-		iommu_dma_init_one_fq(per_cpu_ptr(queue, cpu));
+		iommu_dma_init_one_fq(per_cpu_ptr(queue, cpu), fq_size);
 	cookie->percpu_fq = queue;
 	return 0;
 }
@@ -635,11 +644,16 @@ static bool dev_use_sg_swiotlb(struct device *dev, struct scatterlist *sg,
 static void iommu_dma_init_options(struct iommu_dma_options *options,
 				   struct device *dev)
 {
-	/* Shadowing IOTLB flushes do better with a single queue */
-	if (dev->iommu->shadow_on_flush)
+	/* Shadowing IOTLB flushes do better with a single large queue */
+	if (dev->iommu->shadow_on_flush) {
 		options->qt = IOMMU_DMA_OPTS_SINGLE_QUEUE;
-	else
+		options->fq_timeout = IOVA_SINGLE_FQ_TIMEOUT;
+		options->fq_size = IOVA_SINGLE_FQ_SIZE;
+	} else {
 		options->qt = IOMMU_DMA_OPTS_PER_CPU_QUEUE;
+		options->fq_size = IOVA_DEFAULT_FQ_SIZE;
+		options->fq_timeout = IOVA_DEFAULT_FQ_TIMEOUT;
+	}
 }
 
 /**

-- 
2.39.2

Re: [PATCH v13 4/6] iommu/s390: Disable deferred flush for ISM devices

[Matthew Rosato]

On 9/28/23 10:31 AM, Niklas Schnelle wrote:
> ISM devices are virtual PCI devices used for cross-LPAR communication.
> Unlike real PCI devices ISM devices do not use the hardware IOMMU but
> inspects IOMMU translation tables directly on IOTLB flush (s390 RPCIT
> instruction).
> 
> ISM devices keep their DMA allocations static and only very rarely DMA
> unmap at all. For each IOTLB flush that occurs after unmap the ISM
> devices will however inspect the area of the IOVA space indicated by the
> flush. This means that for the global IOTLB flushes used by the flush
> queue mechanism the entire IOVA space would be inspected. In principle
> this would be fine, albeit potentially unnecessarily slow, it turns out
> however that ISM devices are sensitive to seeing IOVA addresses that are
> currently in use in the IOVA range being flushed. Seeing such in-use
> IOVA addresses will cause the ISM device to enter an error state and
> become unusable.
> 
> Fix this by claiming IOMMU_CAP_DEFERRED_FLUSH only for non-ISM devices.
> This makes sure IOTLB flushes only cover IOVAs that have been unmapped
> and also restricts the range of the IOTLB flush potentially reducing
> latency spikes.
> 
> Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>

Looks like my review tag from v12 got dropped on accident -- no changes since prior version and still looks good to me so

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>

Re: [PATCH v13 0/6] iommu/dma: s390 DMA API conversion and optimized IOTLB flushing

[Joerg Roedel]

On Thu, Sep 28, 2023 at 04:31:34PM +0200, Niklas Schnelle wrote:
> Niklas Schnelle (6):
>       iommu: Allow .iotlb_sync_map to fail and handle s390's -ENOMEM return
>       s390/pci: prepare is_passed_through() for dma-iommu
>       s390/pci: Use dma-iommu layer
>       iommu/s390: Disable deferred flush for ISM devices
>       iommu/dma: Allow a single FQ in addition to per-CPU FQs
>       iommu/dma: Use a large flush queue and timeout for shadow_on_flush

Applied, thanks Niklas.

Re: [PATCH v13 0/6] iommu/dma: s390 DMA API conversion and optimized IOTLB flushing

[Niklas Schnelle]

On Mon, 2023-10-02 at 08:59 +0200, Joerg Roedel wrote:
> On Thu, Sep 28, 2023 at 04:31:34PM +0200, Niklas Schnelle wrote:
> > Niklas Schnelle (6):
> >       iommu: Allow .iotlb_sync_map to fail and handle s390's -ENOMEM return
> >       s390/pci: prepare is_passed_through() for dma-iommu
> >       s390/pci: Use dma-iommu layer
> >       iommu/s390: Disable deferred flush for ISM devices
> >       iommu/dma: Allow a single FQ in addition to per-CPU FQs
> >       iommu/dma: Use a large flush queue and timeout for shadow_on_flush
> 
> Applied, thanks Niklas.
> 

Thank you Joerg. During some more testing I've found a minor issue
where resetting the debug statistics still used the now obsolete
counters that should have been removed. So I'll send a follow up patch,
sorry for not noticing this sooner.

Thanks,
Niklas