This is a note to let you know that I've just added the patch titled vfio/type1: Use follow_pte() to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: vfio-type1-use-follow_pte.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 972c0d0e1e65476566c9cd85ef15d2a075c557a6 Author: Alex Williamson <alex.williamson@xxxxxxxxxx> Date: Tue Feb 16 15:49:34 2021 -0700 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@xxxxxxxxxx> Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx> Reviewed-by: Peter Xu <peterx@xxxxxxxxxx> Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 9cbe058a530f0..6b1e8cba17984 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -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; }