6.8-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
[ Upstream commit 1b265da7ea1e1ae997fa119c2846bb389eb39c6b ]
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@lst.de Link: https://lkml.kernel.org/r/20240324234542.2038726-2-hch@lst.de Signed-off-by: Christoph Hellwig hch@lst.de Reviewed-by: David Hildenbrand david@redhat.com Cc: Andy Lutomirski luto@kernel.org Cc: Dave Hansen dave.hansen@linux.intel.com Cc: Fei Li fei1.li@intel.com Cc: Peter Zijlstra peterz@infradead.org Cc: Ingo Molnar mingo@kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Stable-dep-of: 3d6586008f7b ("drivers/virt/acrn: fix PFNMAP PTE checks in acrn_vm_ram_map()") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/virt/acrn/mm.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/virt/acrn/mm.c b/drivers/virt/acrn/mm.c index fa5d9ca6be570..69c3f619f8819 100644 --- a/drivers/virt/acrn/mm.c +++ b/drivers/virt/acrn/mm.c @@ -171,18 +171,24 @@ int acrn_vm_ram_map(struct acrn_vm *vm, struct acrn_vm_memmap *memmap) 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,