diff options
| author | Gautam Gala <ggala@linux.ibm.com> | 2025-09-24 13:26:44 +0200 |
|---|---|---|
| committer | Claudio Imbrenda <imbrenda@linux.ibm.com> | 2025-09-30 15:58:30 +0200 |
| commit | 5deafa27d9ae040b75d392f60b12e300b42b4792 (patch) | |
| tree | 8171f615eceb121afc3184ba3b367e127d21d326 /arch/s390/include/asm/pgtable.h | |
| parent | 352ccf890a3e91f58bc32503f9afdc161bc2c34a (diff) | |
KVM: s390: Fix to clear PTE when discarding a swapped page
KVM run fails when guests with 'cmm' cpu feature and host are
under memory pressure and use swap heavily. This is because
npages becomes ENOMEN (out of memory) in hva_to_pfn_slow()
which inturn propagates as EFAULT to qemu. Clearing the page
table entry when discarding an address that maps to a swap
entry resolves the issue.
Fixes: 200197908dc4 ("KVM: s390: Refactor and split some gmap helpers")
Cc: stable@vger.kernel.org
Suggested-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Gautam Gala <ggala@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Diffstat (limited to 'arch/s390/include/asm/pgtable.h')
| -rw-r--r-- | arch/s390/include/asm/pgtable.h | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h index 6d8bc27a366e..324f96485604 100644 --- a/arch/s390/include/asm/pgtable.h +++ b/arch/s390/include/asm/pgtable.h @@ -2010,4 +2010,26 @@ static inline unsigned long gmap_pgste_get_pgt_addr(unsigned long *pgt) return res; } +static inline pgste_t pgste_get_lock(pte_t *ptep) +{ + unsigned long value = 0; +#ifdef CONFIG_PGSTE + unsigned long *ptr = (unsigned long *)(ptep + PTRS_PER_PTE); + + do { + value = __atomic64_or_barrier(PGSTE_PCL_BIT, ptr); + } while (value & PGSTE_PCL_BIT); + value |= PGSTE_PCL_BIT; +#endif + return __pgste(value); +} + +static inline void pgste_set_unlock(pte_t *ptep, pgste_t pgste) +{ +#ifdef CONFIG_PGSTE + barrier(); + WRITE_ONCE(*(unsigned long *)(ptep + PTRS_PER_PTE), pgste_val(pgste) & ~PGSTE_PCL_BIT); +#endif +} + #endif /* _S390_PAGE_H */ |