Commit c228f5a0 authored by Niklas Schnelle's avatar Niklas Schnelle Committed by Joerg Roedel
Browse files

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: default avatarNiklas Schnelle <schnelle@linux.ibm.com>
Link: https://lore.kernel.org/r/20221109142903.4080275-3-schnelle@linux.ibm.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 59bbf596

drivers/iommu/s390-iommu.c

+56 −11
Original line number Diff line number Diff line
@@ -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,

	}