Re: [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn

[Auger Eric]

Hi Andrey,

On 6/12/19 1:43 PM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> vaddr_get_pfn() uses provided user pointers for vma lookups, which can
> only by done with untagged pointers.
> 
> Untag user pointers in this function.
> 
> Reviewed-by: Catalin Marinas 
> Reviewed-by: Kees Cook 
> Signed-off-by: Andrey Konovalov 
Reviewed-by: Eric Auger 

Thanks

Eric
> ---
>  drivers/vfio/vfio_iommu_type1.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 3ddc375e7063..528e39a1c2dd 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned 
> long vaddr,
>  
>   down_read(>mmap_sem);
>  
> + vaddr = untagged_addr(vaddr);
> +
>   vma = find_vma_intersection(mm, vaddr, vaddr + 1);
>  
>   if (vma && vma->vm_flags & VM_PFNMAP) {
> 

Re: [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn

[Vincenzo Frascino]

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> vaddr_get_pfn() uses provided user pointers for vma lookups, which can
> only by done with untagged pointers.
> 
> Untag user pointers in this function.
> 
> Reviewed-by: Catalin Marinas 
> Reviewed-by: Kees Cook 
> Signed-off-by: Andrey Konovalov 

Reviewed-by: Vincenzo Frascino 

> ---
>  drivers/vfio/vfio_iommu_type1.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 3ddc375e7063..528e39a1c2dd 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned 
> long vaddr,
>  
>   down_read(>mmap_sem);
>  
> + vaddr = untagged_addr(vaddr);
> +
>   vma = find_vma_intersection(mm, vaddr, vaddr + 1);
>  
>   if (vma && vma->vm_flags & VM_PFNMAP) {
> 

-- 
Regards,
Vincenzo

[PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn

[Andrey Konovalov]

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

vaddr_get_pfn() uses provided user pointers for vma lookups, which can
only by done with untagged pointers.

Untag user pointers in this function.

Reviewed-by: Catalin Marinas 
Reviewed-by: Kees Cook 
Signed-off-by: Andrey Konovalov 
---
 drivers/vfio/vfio_iommu_type1.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 3ddc375e7063..528e39a1c2dd 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned 
long vaddr,
 
down_read(>mmap_sem);
 
+   vaddr = untagged_addr(vaddr);
+
vma = find_vma_intersection(mm, vaddr, vaddr + 1);
 
if (vma && vma->vm_flags & VM_PFNMAP) {
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog