diff options
| author | Juergen Gross <jgross@suse.com> | 2022-11-23 07:45:10 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-11-30 23:49:41 +0100 |
| commit | 4aaf269c768dbacd6268af73fda2ffccaa3f1d88 (patch) | |
| tree | 33b5f4fb5b5fc66701c0e74fc738d6f556cb2c9a /include | |
| parent | mm: add dummy pmd_young() for architectures not having it (diff) | |
| download | linux-4aaf269c768dbacd6268af73fda2ffccaa3f1d88.tar.xz linux-4aaf269c768dbacd6268af73fda2ffccaa3f1d88.zip | |
mm: introduce arch_has_hw_nonleaf_pmd_young()
When running as a Xen PV guests commit eed9a328aa1a ("mm: x86: add
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG") can cause a protection violation in
pmdp_test_and_clear_young():
BUG: unable to handle page fault for address: ffff8880083374d0
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 3026067 P4D 3026067 PUD 3027067 PMD 7fee5067 PTE 8010000008337065
Oops: 0003 [#1] PREEMPT SMP NOPTI
CPU: 7 PID: 158 Comm: kswapd0 Not tainted 6.1.0-rc5-20221118-doflr+ #1
RIP: e030:pmdp_test_and_clear_young+0x25/0x40
This happens because the Xen hypervisor can't emulate direct writes to
page table entries other than PTEs.
This can easily be fixed by introducing arch_has_hw_nonleaf_pmd_young()
similar to arch_has_hw_pte_young() and test that instead of
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG.
Link: https://lkml.kernel.org/r/20221123064510.16225-1-jgross@suse.com
Fixes: eed9a328aa1a ("mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: Yu Zhao <yuzhao@google.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: David Hildenbrand <david@redhat.com> [core changes]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/pgtable.h | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 6b0d59269b33..5f0d7d0b9471 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -267,6 +267,17 @@ static inline int pmdp_clear_flush_young(struct vm_area_struct *vma, #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ #endif +#ifndef arch_has_hw_nonleaf_pmd_young +/* + * Return whether the accessed bit in non-leaf PMD entries is supported on the + * local CPU. + */ +static inline bool arch_has_hw_nonleaf_pmd_young(void) +{ + return IS_ENABLED(CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG); +} +#endif + #ifndef arch_has_hw_pte_young /* * Return whether the accessed bit is supported on the local CPU. |