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vfio/type1: Use follow_pte() 

[ Upstream commit 07956b6269d3ed05d854233d5bb776dca91751dd ]

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()")
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Alex Williamson 2021-02-16 15:49:34 -07:00 committed by Greg Kroah-Hartman
parent 005ed88685
commit e41bb745fd
1 changed files with 13 additions and 2 deletions
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15
drivers/vfio/vfio_iommu_type1.c
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@ -24,6 +24,7 @@
#include <linux/compat.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/mm.h>
@ -339,9 +340,11 @@ 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, &ptep, &ptl);
if (ret) {
bool unlocked = false;
@ -355,9 +358,17 @@ 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, &ptep, &ptl);
if (ret)
return ret;
}
if (write_fault && !pte_write(*ptep))
ret = -EFAULT;
else
*pfn = pte_pfn(*ptep);
pte_unmap_unlock(ptep, ptl);
return ret;
}