From mboxrd@z Thu Jan  1 00:00:00 1970
From: Vincenzo Frascino <vincenzo.frascino@arm.com>
Subject: Re: [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in
 vaddr_get_pfn
Date: Wed, 12 Jun 2019 15:41:57 +0100
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To: Andrey Konovalov <andreyknvl@google.com>, linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-rdma@vger.kernel.org, linux-media@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <will.deacon@arm.com>, Mark Rutland <mark.rutland@arm.com>, Andrew Morton <akpm@linux-foundation.org>, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Kees Cook <keescook@chromium.org>, Yishai Hadas <yishaih@mellanox.com>, Felix Kuehling <Felix.Kuehling@amd.com>, Alexander Deucher <Alexander.Deucher@amd.com>, Christian Koenig <Christian.Koenig@amd.com>, Mauro Carvalho Chehab <mchehab@kernel.org>, Jens Wiklander <jens.wiklander@linaro.org>, Alex Williamson <alex.williamson@redhat.com>, Leon Romanovsky <leon@kernel.org>, Luc Van Oostenryck <luc.vanoostenryck@gmail.com>, Dave Martin <Dave.Martin@arm.com>, Khalid Aziz <khalid.aziz@oracle.com>, enh <enh@google.com>, Jason Gunthorpe <jgg@ziepe.ca>
List-Id: linux-rdma@vger.kernel.org

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 <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  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(&mm->mmap_sem);
>  
> +	vaddr = untagged_addr(vaddr);
> +
>  	vma = find_vma_intersection(mm, vaddr, vaddr + 1);
>  
>  	if (vma && vma->vm_flags & VM_PFNMAP) {
> 

-- 
Regards,
Vincenzo