* [Qemu-devel] [PATCH v2 2/2] vfio iommu: Fix size argument to vfio_find_dma() in pin_pages/unpin_pages
@ 2016-12-06 17:13 Kirti Wankhede
2016-12-06 17:40 ` Alex Williamson
2016-12-06 18:28 ` Kirti Wankhede
0 siblings, 2 replies; 3+ messages in thread
From: Kirti Wankhede @ 2016-12-06 17:13 UTC (permalink / raw)
To: alex.williamson, pbonzini, kraxel, cjia
Cc: qemu-devel, kvm, linux-kernel, Kirti Wankhede
vfio_dma keeps track of address range from (dma->iova + 0) to
(dma->iova + dma->size - 1), while vfio_find_dma() search logic looks for
range from (dma->iova + 1) to (dma->iova + dma->size).
In vfio_find_dma(), when the start address is equal to dma->iova and size
is 0, check for the end of search range makes it to take wrong side of
RB-tree. That fails the search even though the address is present in
mapped dma ranges.
In functions pin_pages and unpin_pages, the iova which is being searched
is base address of page to be pinned or unpinned. So here size should be
set to PAGE_SIZE, as argument to vfio_find_dma.
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
---
drivers/vfio/vfio_iommu_type1.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 8e9e94ccb2ff..023fba7b8d5a 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -581,7 +581,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
struct vfio_pfn *vpfn;
iova = user_pfn[i] << PAGE_SHIFT;
- dma = vfio_find_dma(iommu, iova, 0);
+ dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
if (!dma) {
ret = -EINVAL;
goto pin_unwind;
@@ -622,7 +622,7 @@ pin_unwind:
dma_addr_t iova;
iova = user_pfn[j] << PAGE_SHIFT;
- dma = vfio_find_dma(iommu, iova, 0);
+ dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
vfio_unpin_page_external(dma, iova, do_accounting);
phys_pfn[j] = 0;
}
@@ -659,7 +659,7 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data,
dma_addr_t iova;
iova = user_pfn[i] << PAGE_SHIFT;
- dma = vfio_find_dma(iommu, iova, 0);
+ dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
if (!dma)
goto unpin_exit;
vfio_unpin_page_external(dma, iova, do_accounting);
--
2.7.0
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [Qemu-devel] [PATCH v2 2/2] vfio iommu: Fix size argument to vfio_find_dma() in pin_pages/unpin_pages
2016-12-06 17:13 [Qemu-devel] [PATCH v2 2/2] vfio iommu: Fix size argument to vfio_find_dma() in pin_pages/unpin_pages Kirti Wankhede
@ 2016-12-06 17:40 ` Alex Williamson
2016-12-06 18:28 ` Kirti Wankhede
1 sibling, 0 replies; 3+ messages in thread
From: Alex Williamson @ 2016-12-06 17:40 UTC (permalink / raw)
To: Kirti Wankhede; +Cc: pbonzini, kraxel, cjia, qemu-devel, kvm, linux-kernel
On Tue, 6 Dec 2016 22:43:45 +0530
Kirti Wankhede <kwankhede@nvidia.com> wrote:
> vfio_dma keeps track of address range from (dma->iova + 0) to
> (dma->iova + dma->size - 1), while vfio_find_dma() search logic looks for
> range from (dma->iova + 1) to (dma->iova + dma->size).
Also not true as described in reply to 1/2.
> In vfio_find_dma(), when the start address is equal to dma->iova and size
> is 0, check for the end of search range makes it to take wrong side of
> RB-tree. That fails the search even though the address is present in
> mapped dma ranges.
> In functions pin_pages and unpin_pages, the iova which is being searched
> is base address of page to be pinned or unpinned. So here size should be
> set to PAGE_SIZE, as argument to vfio_find_dma.
>
> Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
> Signed-off-by: Neo Jia <cjia@nvidia.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 8e9e94ccb2ff..023fba7b8d5a 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -581,7 +581,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
> struct vfio_pfn *vpfn;
>
> iova = user_pfn[i] << PAGE_SHIFT;
> - dma = vfio_find_dma(iommu, iova, 0);
> + dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
> if (!dma) {
> ret = -EINVAL;
> goto pin_unwind;
> @@ -622,7 +622,7 @@ pin_unwind:
> dma_addr_t iova;
>
> iova = user_pfn[j] << PAGE_SHIFT;
> - dma = vfio_find_dma(iommu, iova, 0);
> + dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
> vfio_unpin_page_external(dma, iova, do_accounting);
> phys_pfn[j] = 0;
> }
> @@ -659,7 +659,7 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data,
> dma_addr_t iova;
>
> iova = user_pfn[i] << PAGE_SHIFT;
> - dma = vfio_find_dma(iommu, iova, 0);
> + dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
> if (!dma)
> goto unpin_exit;
> vfio_unpin_page_external(dma, iova, do_accounting);
^ permalink raw reply [flat|nested] 3+ messages in thread* [Qemu-devel] [PATCH v2 2/2] vfio iommu: Fix size argument to vfio_find_dma() in pin_pages/unpin_pages
2016-12-06 17:13 [Qemu-devel] [PATCH v2 2/2] vfio iommu: Fix size argument to vfio_find_dma() in pin_pages/unpin_pages Kirti Wankhede
2016-12-06 17:40 ` Alex Williamson
@ 2016-12-06 18:28 ` Kirti Wankhede
1 sibling, 0 replies; 3+ messages in thread
From: Kirti Wankhede @ 2016-12-06 18:28 UTC (permalink / raw)
To: alex.williamson, pbonzini, kraxel, cjia
Cc: qemu-devel, kvm, linux-kernel, Kirti Wankhede
Passing zero for the size to vfio_find_dma() isn't compatible with
matching the start address of an existing vfio_dma. Doing so triggers a
corner case. In vfio_find_dma(), when the start address is equal to
dma->iova and size is 0, check for the end of search range makes it to
take wrong side of RB-tree. That fails the search even though the address
is present in mapped dma ranges.
In functions pin_pages and unpin_pages, the iova which is being searched
is base address of page to be pinned or unpinned. So here size should be
set to PAGE_SIZE, as argument to vfio_find_dma().
Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
---
drivers/vfio/vfio_iommu_type1.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 8e9e94ccb2ff..023fba7b8d5a 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -581,7 +581,7 @@ static int vfio_iommu_type1_pin_pages(void *iommu_data,
struct vfio_pfn *vpfn;
iova = user_pfn[i] << PAGE_SHIFT;
- dma = vfio_find_dma(iommu, iova, 0);
+ dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
if (!dma) {
ret = -EINVAL;
goto pin_unwind;
@@ -622,7 +622,7 @@ pin_unwind:
dma_addr_t iova;
iova = user_pfn[j] << PAGE_SHIFT;
- dma = vfio_find_dma(iommu, iova, 0);
+ dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
vfio_unpin_page_external(dma, iova, do_accounting);
phys_pfn[j] = 0;
}
@@ -659,7 +659,7 @@ static int vfio_iommu_type1_unpin_pages(void *iommu_data,
dma_addr_t iova;
iova = user_pfn[i] << PAGE_SHIFT;
- dma = vfio_find_dma(iommu, iova, 0);
+ dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
if (!dma)
goto unpin_exit;
vfio_unpin_page_external(dma, iova, do_accounting);
--
2.7.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2016-12-06 17:13 [Qemu-devel] [PATCH v2 2/2] vfio iommu: Fix size argument to vfio_find_dma() in pin_pages/unpin_pages Kirti Wankhede
2016-12-06 17:40 ` Alex Williamson
2016-12-06 18:28 ` Kirti Wankhede
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