From add02cfdc9bc2987b0121861d5bb0c7392865be9 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Wed, 23 Aug 2017 15:50:04 +0200 Subject: [PATCH] iommu: Introduce Interface for IOMMU TLB Flushing With the current IOMMU-API the hardware TLBs have to be flushed in every iommu_ops->unmap() call-back. For unmapping large amounts of address space, like it happens when a KVM domain with assigned devices is destroyed, this causes thousands of unnecessary TLB flushes in the IOMMU hardware because the unmap call-back runs for every unmapped physical page. With the TLB Flush Interface and the new iommu_unmap_fast() function introduced here the need to clean the hardware TLBs is removed from the unmapping code-path. Users of iommu_unmap_fast() have to explicitly call the TLB-Flush functions to sync the page-table changes to the hardware. Three functions for TLB-Flushes are introduced: * iommu_flush_tlb_all() - Flushes all TLB entries associated with that domain. TLBs entries are flushed when this function returns. * iommu_tlb_range_add() - This will add a given range to the flush queue for this domain. * iommu_tlb_sync() - Flushes all queued ranges from the hardware TLBs. Returns when the flush is finished. The semantic of this interface is intentionally similar to the iommu_gather_ops from the io-pgtable code. Cc: Alex Williamson Cc: Will Deacon Cc: Robin Murphy Signed-off-by: Joerg Roedel --- drivers/iommu/iommu.c | 32 +++++++++++++++++++++++---- include/linux/iommu.h | 50 ++++++++++++++++++++++++++++++++++++++++++- 2 files changed, 77 insertions(+), 5 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 5499a0387349..31c2b1dc8cfd 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -527,6 +527,8 @@ static int iommu_group_create_direct_mappings(struct iommu_group *group, } + iommu_flush_tlb_all(domain); + out: iommu_put_resv_regions(dev, &mappings); @@ -1547,13 +1549,16 @@ int iommu_map(struct iommu_domain *domain, unsigned long iova, } EXPORT_SYMBOL_GPL(iommu_map); -size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) +static size_t __iommu_unmap(struct iommu_domain *domain, + unsigned long iova, size_t size, + bool sync) { + const struct iommu_ops *ops = domain->ops; size_t unmapped_page, unmapped = 0; - unsigned int min_pagesz; unsigned long orig_iova = iova; + unsigned int min_pagesz; - if (unlikely(domain->ops->unmap == NULL || + if (unlikely(ops->unmap == NULL || domain->pgsize_bitmap == 0UL)) return -ENODEV; @@ -1583,10 +1588,13 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) while (unmapped < size) { size_t pgsize = iommu_pgsize(domain, iova, size - unmapped); - unmapped_page = domain->ops->unmap(domain, iova, pgsize); + unmapped_page = ops->unmap(domain, iova, pgsize); if (!unmapped_page) break; + if (sync && ops->iotlb_range_add) + ops->iotlb_range_add(domain, iova, pgsize); + pr_debug("unmapped: iova 0x%lx size 0x%zx\n", iova, unmapped_page); @@ -1594,11 +1602,27 @@ size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, size_t size) unmapped += unmapped_page; } + if (sync && ops->iotlb_sync) + ops->iotlb_sync(domain); + trace_unmap(orig_iova, size, unmapped); return unmapped; } + +size_t iommu_unmap(struct iommu_domain *domain, + unsigned long iova, size_t size) +{ + return __iommu_unmap(domain, iova, size, true); +} EXPORT_SYMBOL_GPL(iommu_unmap); +size_t iommu_unmap_fast(struct iommu_domain *domain, + unsigned long iova, size_t size) +{ + return __iommu_unmap(domain, iova, size, false); +} +EXPORT_SYMBOL_GPL(iommu_unmap_fast); + size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot) { diff --git a/include/linux/iommu.h b/include/linux/iommu.h index f1ce8e517d8d..50be4fd338e4 100644 --- a/include/linux/iommu.h +++ b/include/linux/iommu.h @@ -167,6 +167,10 @@ struct iommu_resv_region { * @map: map a physically contiguous memory region to an iommu domain * @unmap: unmap a physically contiguous memory region from an iommu domain * @map_sg: map a scatter-gather list of physically contiguous memory chunks + * @flush_tlb_all: Synchronously flush all hardware TLBs for this domain + * @tlb_range_add: Add a given iova range to the flush queue for this domain + * @tlb_sync: Flush all queued ranges from the hardware TLBs and empty flush + * queue * to an iommu domain * @iova_to_phys: translate iova to physical address * @add_device: add device to iommu grouping @@ -199,6 +203,10 @@ struct iommu_ops { size_t size); size_t (*map_sg)(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot); + void (*flush_iotlb_all)(struct iommu_domain *domain); + void (*iotlb_range_add)(struct iommu_domain *domain, + unsigned long iova, size_t size); + void (*iotlb_sync)(struct iommu_domain *domain); phys_addr_t (*iova_to_phys)(struct iommu_domain *domain, dma_addr_t iova); int (*add_device)(struct device *dev); void (*remove_device)(struct device *dev); @@ -286,7 +294,9 @@ extern struct iommu_domain *iommu_get_domain_for_dev(struct device *dev); extern int iommu_map(struct iommu_domain *domain, unsigned long iova, phys_addr_t paddr, size_t size, int prot); extern size_t iommu_unmap(struct iommu_domain *domain, unsigned long iova, - size_t size); + size_t size); +extern size_t iommu_unmap_fast(struct iommu_domain *domain, + unsigned long iova, size_t size); extern size_t default_iommu_map_sg(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg,unsigned int nents, int prot); @@ -343,6 +353,25 @@ extern void iommu_domain_window_disable(struct iommu_domain *domain, u32 wnd_nr) extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev, unsigned long iova, int flags); +static inline void iommu_flush_tlb_all(struct iommu_domain *domain) +{ + if (domain->ops->flush_iotlb_all) + domain->ops->flush_iotlb_all(domain); +} + +static inline void iommu_tlb_range_add(struct iommu_domain *domain, + unsigned long iova, size_t size) +{ + if (domain->ops->iotlb_range_add) + domain->ops->iotlb_range_add(domain, iova, size); +} + +static inline void iommu_tlb_sync(struct iommu_domain *domain) +{ + if (domain->ops->iotlb_sync) + domain->ops->iotlb_sync(domain); +} + static inline size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot) @@ -436,6 +465,12 @@ static inline int iommu_unmap(struct iommu_domain *domain, unsigned long iova, return -ENODEV; } +static inline int iommu_unmap_fast(struct iommu_domain *domain, unsigned long iova, + int gfp_order) +{ + return -ENODEV; +} + static inline size_t iommu_map_sg(struct iommu_domain *domain, unsigned long iova, struct scatterlist *sg, unsigned int nents, int prot) @@ -443,6 +478,19 @@ static inline size_t iommu_map_sg(struct iommu_domain *domain, return -ENODEV; } +static inline void iommu_flush_tlb_all(struct iommu_domain *domain) +{ +} + +static inline void iommu_tlb_range_add(struct iommu_domain *domain, + unsigned long iova, size_t size) +{ +} + +static inline void iommu_tlb_sync(struct iommu_domain *domain) +{ +} + static inline int iommu_domain_window_enable(struct iommu_domain *domain, u32 wnd_nr, phys_addr_t paddr, u64 size, int prot)