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| author | Jann Horn <jannh@google.com> | 2025-01-03 19:39:38 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2025-04-10 14:33:42 +0200 |
| commit | 0708fd6bd8161871bfbadced2ca4319b84ab44fe (patch) | |
| tree | 7c1828115226180b88a922be9a592d1bd7079c6f | |
| parent | 39e32fe65ea43cefbe70df296d39b6578c49c6cd (diff) | |
| download | linux-0708fd6bd8161871bfbadced2ca4319b84ab44fe.tar.gz linux-0708fd6bd8161871bfbadced2ca4319b84ab44fe.tar.bz2 linux-0708fd6bd8161871bfbadced2ca4319b84ab44fe.zip | |
x86/mm: Fix flush_tlb_range() when used for zapping normal PMDs
commit 3ef938c3503563bfc2ac15083557f880d29c2e64 upstream.
On the following path, flush_tlb_range() can be used for zapping normal
PMD entries (PMD entries that point to page tables) together with the PTE
entries in the pointed-to page table:
collapse_pte_mapped_thp
pmdp_collapse_flush
flush_tlb_range
The arm64 version of flush_tlb_range() has a comment describing that it can
be used for page table removal, and does not use any last-level
invalidation optimizations. Fix the X86 version by making it behave the
same way.
Currently, X86 only uses this information for the following two purposes,
which I think means the issue doesn't have much impact:
- In native_flush_tlb_multi() for checking if lazy TLB CPUs need to be
IPI'd to avoid issues with speculative page table walks.
- In Hyper-V TLB paravirtualization, again for lazy TLB stuff.
The patch "x86/mm: only invalidate final translations with INVLPGB" which
is currently under review (see
<https://lore.kernel.org/all/20241230175550.4046587-13-riel@surriel.com/>)
would probably be making the impact of this a lot worse.
Fixes: 016c4d92cd16 ("x86/mm/tlb: Add freed_tables argument to flush_tlb_mm_range")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20250103-x86-collapse-flush-fix-v1-1-3c521856cfa6@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/x86/include/asm/tlbflush.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index d1eb6bbfd39e..5abe6c3d982a 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -228,7 +228,7 @@ void flush_tlb_multi(const struct cpumask *cpumask, flush_tlb_mm_range((vma)->vm_mm, start, end, \ ((vma)->vm_flags & VM_HUGETLB) \ ? huge_page_shift(hstate_vma(vma)) \ - : PAGE_SHIFT, false) + : PAGE_SHIFT, true) extern void flush_tlb_all(void); extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, |