Merge branch 'iommu-memory-accounting' into core

Merge patch-set from Jason:

	"Let iommufd charge IOPTE allocations to the memory cgroup"

Description:

IOMMUFD follows the same design as KVM and uses memory cgroups to limit
the amount of kernel memory a iommufd file descriptor can pin down. The
various internal data structures already use GFP_KERNEL_ACCOUNT to charge
its own memory.

However, one of the biggest consumers of kernel memory is the IOPTEs
stored under the iommu_domain and these allocations are not tracked.

This series is the first step in fixing it.

The iommu driver contract already includes a 'gfp' argument to the
map_pages op, allowing iommufd to specify GFP_KERNEL_ACCOUNT and then
having the driver allocate the IOPTE tables with that flag will capture a
significant amount of the allocations.

Update the iommu_map() API to pass in the GFP argument, and fix all call
sites. Replace iommu_map_atomic().

Audit the "enterprise" iommu drivers to make sure they do the right thing.
Intel and S390 ignore the GFP argument and always use GFP_ATOMIC. This is
problematic for iommufd anyhow, so fix it. AMD and ARM SMMUv2/3 are
already correct.

A follow up series will be needed to capture the allocations made when the
iommu_domain itself is allocated, which will complete the job.

Link: https://lore.kernel.org/linux-iommu/0-v3-76b587fe28df+6e3-iommu_map_gfp_jgg@nvidia.com/

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 8e023f032b76..99b2646cb5c7 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -716,7 +716,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 	if (!iova)
 		return DMA_MAPPING_ERROR;
 
-	if (iommu_map_atomic(domain, iova, phys - iova_off, size, prot)) {
+	if (iommu_map(domain, iova, phys - iova_off, size, prot, GFP_ATOMIC)) {
 		iommu_dma_free_iova(cookie, iova, size, NULL);
 		return DMA_MAPPING_ERROR;
 	}
@@ -825,7 +825,14 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
 	if (!iova)
 		goto out_free_pages;
 
-	if (sg_alloc_table_from_pages(sgt, pages, count, 0, size, GFP_KERNEL))
+	/*
+	 * Remove the zone/policy flags from the GFP - these are applied to the
+	 * __iommu_dma_alloc_pages() but are not used for the supporting
+	 * internal allocations that follow.
+	 */
+	gfp &= ~(__GFP_DMA | __GFP_DMA32 | __GFP_HIGHMEM | __GFP_COMP);
+
+	if (sg_alloc_table_from_pages(sgt, pages, count, 0, size, gfp))
 		goto out_free_iova;
 
 	if (!(ioprot & IOMMU_CACHE)) {
@@ -836,7 +843,8 @@ static struct page **__iommu_dma_alloc_noncontiguous(struct device *dev,
 			arch_dma_prep_coherent(sg_page(sg), sg->length);
 	}
 
-	ret = iommu_map_sg_atomic(domain, iova, sgt->sgl, sgt->orig_nents, ioprot);
+	ret = iommu_map_sg(domain, iova, sgt->sgl, sgt->orig_nents, ioprot,
+			   gfp);
 	if (ret < 0 || ret < size)
 		goto out_free_sg;
 
@@ -1284,7 +1292,7 @@ static int iommu_dma_map_sg(struct device *dev, struct scatterlist *sg,
 	 * We'll leave any physical concatenation to the IOMMU driver's
 	 * implementation - it knows better than we do.
 	 */
-	ret = iommu_map_sg_atomic(domain, iova, sg, nents, prot);
+	ret = iommu_map_sg(domain, iova, sg, nents, prot, GFP_ATOMIC);
 	if (ret < 0 || ret < iova_len)
 		goto out_free_iova;
 
@@ -1618,7 +1626,7 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
 	if (!iova)
 		goto out_free_page;
 
-	if (iommu_map(domain, iova, msi_addr, size, prot))
+	if (iommu_map(domain, iova, msi_addr, size, prot, GFP_KERNEL))
 		goto out_free_iova;
 
 	INIT_LIST_HEAD(&msi_page->list);