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List:       linux-rdma
Subject:    [PATCH v14 16/17] vfio/type1, arm64: untag user pointers in vaddr_get_pfn
From:       Andrey Konovalov <andreyknvl () google ! com>
Date:       2019-04-30 13:25:12
Message-ID: c9ef2282b1860e3ca6da28a4d599c24ff7147bb7.1556630205.git.andreyknvl () google ! com
[Download RAW message or body]

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) {
-- 
2.21.0.593.g511ec345e18-goog

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