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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>
This commit is contained in:
Niklas Schnelle 2022-11-09 15:29:00 +01:00 committed by Joerg Roedel
parent 59bbf59679
commit c228f5a043
1 changed files with 56 additions and 11 deletions
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67
drivers/iommu/s390-iommu.c
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@ -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,
}