diff options
| author |   Paolo Bonzini <pbonzini@redhat.com> | 2024-04-11 13:06:24 -0400 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2024-04-12 04:41:14 -0400 |
| commit | 531f5200243242d79e99751e4f8a16592afd121f (patch) | |
| tree | b892d8ce293bd19e4fe634c2a305a5d041b5ac39 /mm/memory.c | |
| parent | Merge tag 'kvm-riscv-fixes-6.9-1' of https://github.com/kvm-riscv/linux into HEAD (diff) | |
| parent | mm: replace set_pte_at_notify() with just set_pte_at() (diff) | |
| download | wireguard-linux-531f5200243242d79e99751e4f8a16592afd121f.tar.xz wireguard-linux-531f5200243242d79e99751e4f8a16592afd121f.zip | |
Merge branch 'mm-delete-change-gpte' into HEAD
The .change_pte() MMU notifier callback was intended as an optimization
and for this reason it was initially called without a surrounding
mmu_notifier_invalidate_range_{start,end}() pair. It was only ever
implemented by KVM (which was also the original user of MMU notifiers)
and the rules on when to call set_pte_at_notify() rather than set_pte_at()
have always been pretty obscure.
It may seem a miracle that it has never caused any hard to trigger
bugs, but there's a good reason for that: KVM's implementation has
been nonfunctional for a good part of its existence. Already in
2012, commit 6bdb913f0a70 ("mm: wrap calls to set_pte_at_notify with
invalidate_range_start and invalidate_range_end", 2012-10-09) changed the
.change_pte() callback to occur within an invalidate_range_start/end()
pair; and because KVM unmaps the sPTEs during .invalidate_range_start(),
.change_pte() has no hope of finding a sPTE to change.
Therefore, all the code for .change_pte() can be removed from both KVM
and mm/, and set_pte_at_notify() can be replaced with just set_pte_at().
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 7 |
1 files changed, 1 insertions, 6 deletions
diff --git a/mm/memory.c b/mm/memory.c index f2bc6dd15eb8..9a6f4d8aa379 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -3327,13 +3327,8 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) ptep_clear_flush(vma, vmf->address, vmf->pte); folio_add_new_anon_rmap(new_folio, vma, vmf->address); folio_add_lru_vma(new_folio, vma); - /* - * We call the notify macro here because, when using secondary - * mmu page tables (such as kvm shadow page tables), we want the - * new page to be mapped directly into the secondary page table. - */ BUG_ON(unshare && pte_write(entry)); - set_pte_at_notify(mm, vmf->address, vmf->pte, entry); + set_pte_at(mm, vmf->address, vmf->pte, entry); update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); if (old_folio) { /* |