The patch titled
Subject: virt: acrn: stop using follow_pfn
has been added to the -mm mm-unstable branch. Its filename is
virt-acrn-stop-using-follow_pfn.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/virt-acrn-stop-using-follow_pfn.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Christoph Hellwig <hch@xxxxxx>
Subject: virt: acrn: stop using follow_pfn
Date: Mon, 25 Mar 2024 07:45:40 +0800
Patch series "remove follow_pfn".
This series open codes follow_pfn in the only remaining caller, although
the code there remains questionable. It then also moves follow_phys into
the only user and simplifies it a bit.
This patch (of 3):
Switch from follow_pfn to follow_pte so that we can get rid of follow_pfn.
Note that this doesn't fix any of the pre-existing raciness and lack of
permission checking in the code.
Link: https://lkml.kernel.org/r/20240324234542.2038726-1-hch@xxxxxx
Link: https://lkml.kernel.org/r/20240324234542.2038726-2-hch@xxxxxx
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Fei Li <fei1.li@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/virt/acrn/mm.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/drivers/virt/acrn/mm.c~virt-acrn-stop-using-follow_pfn
+++ a/drivers/virt/acrn/mm.c
@@ -172,18 +172,24 @@ int acrn_vm_ram_map(struct acrn_vm *vm,
mmap_read_lock(current->mm);
vma = vma_lookup(current->mm, memmap->vma_base);
if (vma && ((vma->vm_flags & VM_PFNMAP) != 0)) {
+ spinlock_t *ptl;
+ pte_t *ptep;
+
if ((memmap->vma_base + memmap->len) > vma->vm_end) {
mmap_read_unlock(current->mm);
return -EINVAL;
}
- ret = follow_pfn(vma, memmap->vma_base, &pfn);
- mmap_read_unlock(current->mm);
+ ret = follow_pte(vma->vm_mm, memmap->vma_base, &ptep, &ptl);
if (ret < 0) {
+ mmap_read_unlock(current->mm);
dev_dbg(acrn_dev.this_device,
"Failed to lookup PFN at VMA:%pK.\n", (void *)memmap->vma_base);
return ret;
}
+ pfn = pte_pfn(ptep_get(ptep));
+ pte_unmap_unlock(ptep, ptl);
+ mmap_read_unlock(current->mm);
return acrn_mm_region_add(vm, memmap->user_vm_pa,
PFN_PHYS(pfn), memmap->len,
_
Patches currently in -mm which might be from hch@xxxxxx are
virt-acrn-stop-using-follow_pfn.patch
mm-remove-follow_pfn.patch
mm-move-follow_phys-to-arch-x86-mm-pat-memtypec.patch
