The following commit has been merged into the x86/mm branch of tip: Commit-ID: 63887c9f02030afd042c125052ad60680f7c21b2 Gitweb: https://git.kernel.org/tip/63887c9f02030afd042c125052ad60680f7c21b2 Author: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx> AuthorDate: Tue, 04 Feb 2025 18:33:50 +01:00 Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> CommitterDate: Wed, 05 Feb 2025 16:23:17 -08:00 x86: Compare physical instead of virtual PGD addresses This is a preparatory patch for when pointers have tags in their upper address bits. But it's a harmless change on its own. The mm->pgd virtual address may be tagged because it came out of the allocator at some point. The __va(read_cr3_pa()) address will never be tagged (the tag bits are all 1's). A direct pointer value comparison would fail if one is tagged and the other is not. To fix this, just compare the physical addresses which are never affected by tagging. [ dhansen: subject and changelog munging ] Signed-off-by: Maciej Wieczor-Retman <maciej.wieczor-retman@xxxxxxxxx> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx> Link: https://lore.kernel.org/all/fde443d0e67f76a51e7ab4e96647705840f53ddb.1738686764.git.maciej.wieczor-retman%40intel.com --- arch/x86/mm/tlb.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 6cf881a..ffc25b3 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1325,7 +1325,7 @@ bool nmi_uaccess_okay(void) if (loaded_mm != current_mm) return false; - VM_WARN_ON_ONCE(current_mm->pgd != __va(read_cr3_pa())); + VM_WARN_ON_ONCE(__pa(current_mm->pgd) != read_cr3_pa()); return true; }
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