Commit 5d8b3e75 authored Mar 17, 2017 by Alexey Kardashevskiy Committed by Greg Kroah-Hartman Mar 22, 2017

vfio/spapr: Postpone allocation of userspace version of TCE table



[ Upstream commit 39701e56f5f16ea0cf8fc9e8472e645f8de91d23 ]

The iommu_table struct manages a hardware TCE table and a vmalloc'd
table with corresponding userspace addresses. Both are allocated when
the default DMA window is created and this happens when the very first
group is attached to a container.

As we are going to allow the userspace to configure container in one
memory context and pas container fd to another, we have to postpones
such allocations till a container fd is passed to the destination
user process so we would account locked memory limit against the actual
container user constrainsts.

This postpones the it_userspace array allocation till it is used first
time for mapping. The unmapping patch already checks if the array is
allocated.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 3c0cbb47

drivers/vfio/vfio_iommu_spapr_tce.c

+7 −13

Original line number	Diff line number	Diff line
		@@ -509,6 +509,12 @@ static long tce_iommu_build_v2(struct tce_container *container,
		unsigned long hpa;
		enum dma_data_direction dirtmp;

		if (!tbl->it_userspace) {
		ret = tce_iommu_userspace_view_alloc(tbl);
		if (ret)
		return ret;
		}

		for (i = 0; i < pages; ++i) {
		struct mm_iommu_table_group_mem_t *mem = NULL;
		unsigned long *pua = IOMMU_TABLE_USERSPACE_ENTRY(tbl,
		@@ -582,15 +588,6 @@ static long tce_iommu_create_table(struct tce_container *container,
		WARN_ON(!ret && !(*ptbl)->it_ops->free);
		WARN_ON(!ret && ((*ptbl)->it_allocated_size != table_size));

		if (!ret && container->v2) {
		ret = tce_iommu_userspace_view_alloc(*ptbl);
		if (ret)
		(ptbl)->it_ops->free(ptbl);
		}

		if (ret)
		decrement_locked_vm(table_size >> PAGE_SHIFT);

		return ret;
		}

		@@ -1062,10 +1059,7 @@ static int tce_iommu_take_ownership(struct tce_container *container,
		if (!tbl \|\| !tbl->it_map)
		continue;

		rc = tce_iommu_userspace_view_alloc(tbl);
		if (!rc)
		rc = iommu_take_ownership(tbl);

		if (rc) {
		for (j = 0; j < i; ++j)
		iommu_release_ownership(