iommu/s390: Add I/O TLB ops

Currently s390-iommu does an I/O TLB flush (RPCIT) for every update of
the I/O translation table explicitly. For one this is wasteful since
RPCIT can be skipped after a mapping operation if zdev->tlb_refresh is
unset. Moreover we can do a single RPCIT for a range of pages including
whne doing lazy unmapping.

Thankfully both of these optimizations can be achieved by implementing
the IOMMU operations common code provides for the different types of I/O
tlb flushes:

 * flush_iotlb_all: Flushes the I/O TLB for the entire IOVA space
 * iotlb_sync:  Flushes the I/O TLB for a range of pages that can be
   gathered up, for example to implement lazy unmapping.
 * iotlb_sync_map: Flushes the I/O TLB after a mapping operation

Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20221109142903.4080275-3-schnelle@linux.ibm.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index e2c886b..9771bce 100644 (file)
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -199,14 +199,63 @@ static void s390_iommu_release_device(struct device *dev)
                __s390_iommu_detach_device(zdev);
 }
 
+static void s390_iommu_flush_iotlb_all(struct iommu_domain *domain)
+{
+       struct s390_domain *s390_domain = to_s390_domain(domain);
+       struct zpci_dev *zdev;
+       unsigned long flags;
+
+       spin_lock_irqsave(&s390_domain->list_lock, flags);
+       list_for_each_entry(zdev, &s390_domain->devices, iommu_list) {
+               zpci_refresh_trans((u64)zdev->fh << 32, zdev->start_dma,
+                                  zdev->end_dma - zdev->start_dma + 1);
+       }
+       spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+}
+
+static void s390_iommu_iotlb_sync(struct iommu_domain *domain,
+                                 struct iommu_iotlb_gather *gather)
+{
+       struct s390_domain *s390_domain = to_s390_domain(domain);
+       size_t size = gather->end - gather->start + 1;
+       struct zpci_dev *zdev;
+       unsigned long flags;
+
+       /* If gather was never added to there is nothing to flush */
+       if (!gather->end)
+               return;
+
+       spin_lock_irqsave(&s390_domain->list_lock, flags);
+       list_for_each_entry(zdev, &s390_domain->devices, iommu_list) {
+               zpci_refresh_trans((u64)zdev->fh << 32, gather->start,
+                                  size);
+       }
+       spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+}
+
+static void 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;
+       unsigned long flags;
+
+       spin_lock_irqsave(&s390_domain->list_lock, flags);
+       list_for_each_entry(zdev, &s390_domain->devices, iommu_list) {
+               if (!zdev->tlb_refresh)
+                       continue;
+               zpci_refresh_trans((u64)zdev->fh << 32,
+                                  iova, size);
+       }
+       spin_unlock_irqrestore(&s390_domain->list_lock, flags);
+}
+
 static int s390_iommu_update_trans(struct s390_domain *s390_domain,
                                   phys_addr_t pa, dma_addr_t dma_addr,
                                   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, i;
-       struct zpci_dev *zdev;
        unsigned long *entry;
        int rc = 0;
 
@@ -225,15 +274,6 @@ static int s390_iommu_update_trans(struct s390_domain *s390_domain,
                dma_addr += PAGE_SIZE;
        }
 
-       spin_lock(&s390_domain->list_lock);
-       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;
-       }
-       spin_unlock(&s390_domain->list_lock);
-
 undo_cpu_trans:
        if (rc && ((flags & ZPCI_PTE_VALID_MASK) == ZPCI_PTE_VALID)) {
                flags = ZPCI_PTE_INVALID;
@@ -340,6 +380,8 @@ static size_t s390_iommu_unmap_pages(struct iommu_domain *domain,
        if (rc)
                return 0;
 
+       iommu_iotlb_gather_add_range(gather, iova, size);
+
        return size;
 }
 
@@ -384,6 +426,9 @@ static const struct iommu_ops s390_iommu_ops = {
                .detach_dev     = s390_iommu_detach_device,
                .map_pages      = s390_iommu_map_pages,
                .unmap_pages    = s390_iommu_unmap_pages,
+               .flush_iotlb_all = s390_iommu_flush_iotlb_all,
+               .iotlb_sync      = s390_iommu_iotlb_sync,
+               .iotlb_sync_map  = s390_iommu_iotlb_sync_map,
                .iova_to_phys   = s390_iommu_iova_to_phys,
                .free           = s390_domain_free,
        }