[for-4.4,13/19] vfio/spapr: Postpone allocation of userspace version of TCE table

Message ID 1490458699-24484-14-git-send-email-sumit.semwal@linaro.org
State New
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Series
  • Stable commits from Ubuntu Yakkety 4.9-lts
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Commit Message

Sumit Semwal March 25, 2017, 4:18 p.m.
From: Alexey Kardashevskiy <aik@ozlabs.ru>


[ 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>

Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

---
 drivers/vfio/vfio_iommu_spapr_tce.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

-- 
2.7.4

Patch

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 0582b72..1a9f18b 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -511,6 +511,12 @@  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,
@@ -584,15 +590,6 @@  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;
 }
 
@@ -1064,10 +1061,7 @@  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);
-
+		rc = iommu_take_ownership(tbl);
 		if (rc) {
 			for (j = 0; j < i; ++j)
 				iommu_release_ownership(