[RFC 04/16] iommu/dma: Provide an interface to allow preallocate IOVA

Leon Romanovsky
2024-03-05T13:36:21Z

Separate IOVA allocation to dedicated callback so it will allow
cache of IOVA and reuse it in fast paths for devices which support
ODP (on-demand-paging) mechanism.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---
drivers/iommu/dma-iommu.c | 50 +++++++++++++++++++++++++++++----------
1 file changed, 38 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 50ccc4f1ef81..e55726783501 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -356,7 +356,7 @@ int iommu_dma_init_fq(struct iommu_domain *domain)
atomic_set(&cookie->fq_timer_on, 0);
/*
* Prevent incomplete fq state being observable. Pairs with path from
- * __iommu_dma_unmap() through iommu_dma_free_iova() to queue_iova()
+ * __iommu_dma_unmap() through __iommu_dma_free_iova() to queue_iova()
*/
smp_wmb();
WRITE_ONCE(cookie->fq_domain, domain);
@@ -760,7 +760,7 @@ static int dma_info_to_prot(enum dma_data_direction dir, bool coherent,
}
}

-static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
+static dma_addr_t __iommu_dma_alloc_iova(struct iommu_domain *domain,
size_t size, u64 dma_limit, struct device *dev)
{
struct iommu_dma_cookie *cookie = domain->iova_cookie;
@@ -806,7 +806,7 @@ static dma_addr_t iommu_dma_alloc_iova(struct iommu_domain *domain,
return (dma_addr_t)iova << shift;
}

-static void iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
+static void __iommu_dma_free_iova(struct iommu_dma_cookie *cookie,
dma_addr_t iova, size_t size, struct iommu_iotlb_gather *gather)
{
struct iova_domain *iovad = &cookie->iovad;
@@ -843,7 +843,7 @@ static void __iommu_dma_unmap(struct device *dev, dma_addr_t dma_addr,

if (!iotlb_gather.queued)
iommu_iotlb_sync(domain, &iotlb_gather);
- iommu_dma_free_iova(cookie, dma_addr, size, &iotlb_gather);
+ __iommu_dma_free_iova(cookie, dma_addr, size, &iotlb_gather);
}

static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
@@ -861,12 +861,12 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,

size = iova_align(iovad, size + iova_off);

- iova = iommu_dma_alloc_iova(domain, size, dma_mask, dev);
+ iova = __iommu_dma_alloc_iova(domain, size, dma_mask, dev);
if (!iova)
return DMA_MAPPING_ERROR;

if (iommu_map(domain, iova, phys - iova_off, size, prot, GFP_ATOMIC)) {
- iommu_dma_free_iova(cookie, iova, size, NULL);
+ __iommu_dma_free_iova(cookie, iova, size, NULL);
return DMA_MAPPING_ERROR;
}
return iova + iova_off;
@@ -970,7 +970,7 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
return NULL;

size = iova_align(iovad, size);
- iova = iommu_dma_alloc_iova(domain, size, dev->coherent_dma_mask, dev);
+ iova = __iommu_dma_alloc_iova(domain, size, dev->coherent_dma_mask, dev);
if (!iova)
goto out_free_pages;

@@ -1004,7 +1004,7 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
out_free_sg:
sg_free_table(sgt);
out_free_iova:
- iommu_dma_free_iova(cookie, iova, size, NULL);
+ __iommu_dma_free_iova(cookie, iova, size, NULL);
out_free_pages:
__iommu_dma_free_pages(pages, count);
return NULL;
@@ -1436,7 +1436,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
if (!iova_len)
return __finalise_sg(dev, sg, nents, 0);

- iova = iommu_dma_alloc_iova(domain, iova_len, dma_get_mask(dev), dev);
+ iova = __iommu_dma_alloc_iova(domain, iova_len, dma_get_mask(dev), dev);
if (!iova) {
ret = -ENOMEM;
goto out_restore_sg;
@@ -1453,7 +1453,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
return __finalise_sg(dev, sg, nents, iova);

out_free_iova:
- iommu_dma_free_iova(cookie, iova, iova_len, NULL);
+ __iommu_dma_free_iova(cookie, iova, iova_len, NULL);
out_restore_sg:
__invalidate_sg(sg, nents);
out:
@@ -1706,6 +1706,30 @@ static size_t iommu_dma_opt_mapping_size(void)
return iova_rcache_range();
}

+static dma_addr_t iommu_dma_alloc_iova(struct device *dev, size_t size)
+{
+ struct iommu_domain *domain = iommu_get_dma_domain(dev);
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iova_domain *iovad = &cookie->iovad;
+ dma_addr_t dma_mask = dma_get_mask(dev);
+
+ size = iova_align(iovad, size);
+ return __iommu_dma_alloc_iova(domain, size, dma_mask, dev);
+}
+
+static void iommu_dma_free_iova(struct device *dev, dma_addr_t iova,
+ size_t size)
+{
+ struct iommu_domain *domain = iommu_get_dma_domain(dev);
+ struct iommu_dma_cookie *cookie = domain->iova_cookie;
+ struct iova_domain *iovad = &cookie->iovad;
+ struct iommu_iotlb_gather iotlb_gather;
+
+ size = iova_align(iovad, size);
+ iommu_iotlb_gather_init(&iotlb_gather);
+ __iommu_dma_free_iova(cookie, iova, size, &iotlb_gather);
+}
+
static const struct dma_map_ops iommu_dma_ops = {
.flags = DMA_F_PCI_P2PDMA_SUPPORTED,
.alloc = iommu_dma_alloc,
@@ -1728,6 +1752,8 @@ static const struct dma_map_ops iommu_dma_ops = {
.unmap_resource = iommu_dma_unmap_resource,
.get_merge_boundary = iommu_dma_get_merge_boundary,
.opt_mapping_size = iommu_dma_opt_mapping_size,
+ .alloc_iova = iommu_dma_alloc_iova,
+ .free_iova = iommu_dma_free_iova,
};

/*
@@ -1776,7 +1802,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
if (!msi_page)
return NULL;

- iova = iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
+ iova = __iommu_dma_alloc_iova(domain, size, dma_get_mask(dev), dev);
if (!iova)
goto out_free_page;

@@ -1790,7 +1816,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
return msi_page;

out_free_iova:
- iommu_dma_free_iova(cookie, iova, size, NULL);
+ __iommu_dma_free_iova(cookie, iova, size, NULL);
out_free_page:
kfree(msi_page);
return NULL;
--
2.44.0