lkml.org 
[lkml]   [2021]   [Feb]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] vfio/type1: Use follow_pte()
On Fri, Feb 12, 2021 at 12:01:50PM -0700, Alex Williamson wrote:
> follow_pfn() doesn't make sure that we're using the correct page
> protections, get the pte with follow_pte() so that we can test
> protections and get the pfn from the pte.
>
> Fixes: 5cbf3264bc71 ("vfio/type1: Fix VA->PA translation for PFNMAP VMAs in vaddr_get_pfn()")
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++--
> 1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index ec9fd95a138b..90715413c3d9 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -463,9 +463,11 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
> unsigned long vaddr, unsigned long *pfn,
> bool write_fault)
> {
> + pte_t *ptep;
> + spinlock_t *ptl;
> int ret;
>
> - ret = follow_pfn(vma, vaddr, pfn);
> + ret = follow_pte(vma->vm_mm, vaddr, NULL, &ptep, NULL, &ptl);
> if (ret) {
> bool unlocked = false;
>
> @@ -479,9 +481,17 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
> if (ret)
> return ret;
>
> - ret = follow_pfn(vma, vaddr, pfn);
> + ret = follow_pte(vma->vm_mm, vaddr, NULL, &ptep, NULL, &ptl);

commit 9fd6dad1261a541b3f5fa7dc5b152222306e6702 in linux-next is what
export's follow_pte and it uses a different signature:

+int follow_pte(struct mm_struct *mm, unsigned long address,
+ pte_t **ptepp, spinlock_t **ptlp)

Recommend you send this patch for rc1 once the right stuff lands in
Linus's tree

Otherwise it looks OK

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

\
 
 \ /
  Last update: 2021-02-12 20:10    [W:0.047 / U:2.168 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site