From aa4cc17b34187d2fad45513d02071a3ae34f0ef1 Mon Sep 17 00:00:00 2001
From: John Garry <john.garry@huawei.com>
Date: Thu, 14 Jul 2022 19:15:25 +0800
Subject: [PATCH] dma-iommu: add iommu_dma_opt_mapping_size()
[ Upstream commit 6d9870b7e5def2450e21316515b9efc0529204dd ]
Add the IOMMU callback for DMA mapping API dma_opt_mapping_size(), which
allows the drivers to know the optimal mapping limit and thus limit the
requested IOVA lengths.
This value is based on the IOVA rcache range limit, as IOVAs allocated
above this limit must always be newly allocated, which may be quite slow.
Signed-off-by: John Garry <john.garry@huawei.com>
Reviewed-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Stable-dep-of: afc5aa46ed56 ("iommu/dma: Force swiotlb_max_mapping_size on an untrusted device")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/iommu/dma-iommu.c | 6 ++++++
drivers/iommu/iova.c | 5 +++++
include/linux/iova.h | 2 ++
3 files changed, 13 insertions(+)
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8cd63e6ccd2c..a76a46e94a60 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -1291,6 +1291,11 @@ static unsigned long iommu_dma_get_merge_boundary(struct device *dev)
return (1UL << __ffs(domain->pgsize_bitmap)) - 1;
}
+static size_t iommu_dma_opt_mapping_size(void)
+{
+ return iova_rcache_range();
+}
+
static const struct dma_map_ops iommu_dma_ops = {
.alloc = iommu_dma_alloc,
.free = iommu_dma_free,
@@ -1313,6 +1318,7 @@ static const struct dma_map_ops iommu_dma_ops = {
.map_resource = iommu_dma_map_resource,
.unmap_resource = iommu_dma_unmap_resource,
.get_merge_boundary = iommu_dma_get_merge_boundary,
+ .opt_mapping_size = iommu_dma_opt_mapping_size,
};
/*
diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c
index 0835f32e040a..f6dfb9e45e95 100644
--- a/drivers/iommu/iova.c
+++ b/drivers/iommu/iova.c
@@ -27,6 +27,11 @@ static void free_iova_rcaches(struct iova_domain *iovad);
static void fq_destroy_all_entries(struct iova_domain *iovad);
static void fq_flush_timeout(struct timer_list *t);
+unsigned long iova_rcache_range(void)
+{
+ return PAGE_SIZE << (IOVA_RANGE_CACHE_MAX_SIZE - 1);
+}
+
static int iova_cpuhp_dead(unsigned int cpu, struct hlist_node *node)
{
struct iova_domain *iovad;
diff --git a/include/linux/iova.h b/include/linux/iova.h
index 6b6cc104e300..9aa0acf9820a 100644
--- a/include/linux/iova.h
+++ b/include/linux/iova.h
@@ -137,6 +137,8 @@ static inline unsigned long iova_pfn(struct iova_domain *iovad, dma_addr_t iova)
int iova_cache_get(void);
void iova_cache_put(void);
+unsigned long iova_rcache_range(void);
+
void free_iova(struct iova_domain *iovad, unsigned long pfn);
void __free_iova(struct iova_domain *iovad, struct iova *iova);
struct iova *alloc_iova(struct iova_domain *iovad, unsigned long size,