[PATCH v15 16/17] vfio/type1, arm64: untag user pointers in vaddr_get_pfn

Andrey Konovalov
2019-05-06T16:32:06Z

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.

Signed-off-by: Andrey Konovalov <andreyknvl@google.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 d0f731c9920a..5daa966d799e 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -382,6 +382,8 @@ 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) {
--
2.21.0.1020.gf2820cf01a-goog