lkml.org 
[lkml]   [2020]   [Oct]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3 11/16] vfio/type1: Mark follow_pfn as unsafe
Date
The code seems to stuff these pfns into iommu pts (or something like
that, I didn't follow), but there's no mmu_notifier to ensure that
access is synchronized with pte updates.

Hence mark these as unsafe. This means that with
CONFIG_STRICT_FOLLOW_PFN, these will be rejected.

Real fix is to wire up an mmu_notifier ... somehow. Probably means any
invalidate is a fatal fault for this vfio device, but then this
shouldn't ever happen if userspace is reasonable.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: linux-mm@kvack.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: linux-media@vger.kernel.org
Cc: Alex Williamson <alex.williamson@redhat.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: kvm@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.com>
---
drivers/vfio/vfio_iommu_type1.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 5fbf0c1f7433..a4d53f3d0a35 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -421,7 +421,7 @@ static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
{
int ret;

- ret = follow_pfn(vma, vaddr, pfn);
+ ret = unsafe_follow_pfn(vma, vaddr, pfn);
if (ret) {
bool unlocked = false;

@@ -435,7 +435,7 @@ 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 = unsafe_follow_pfn(vma, vaddr, pfn);
}

return ret;
--
2.28.0
\
 
 \ /
  Last update: 2020-10-21 10:58    [W:3.942 / U:0.264 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site