diff options
| author | David Matlack <dmatlack@google.com> | 2023-10-27 10:26:38 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-12-01 07:51:55 -0800 |
| commit | 1aa4bb916808503bf6fedd00f50f2077f91cebaa (patch) | |
| tree | 134ef53022e7f3f5eadf7f148d55be0b346fb3bb /arch/x86/kvm/mmu/mmu.c | |
| parent | e9e60c82fe391d04db55a91c733df4a017c28b2f (diff) | |
KVM: x86/mmu: Fix off-by-1 when splitting huge pages during CLEAR
Fix an off-by-1 error when passing in the range of pages to
kvm_mmu_try_split_huge_pages() during CLEAR_DIRTY_LOG. Specifically, end
is the last page that needs to be split (inclusive) so pass in `end + 1`
since kvm_mmu_try_split_huge_pages() expects the `end` to be
non-inclusive.
At worst this will cause a huge page to be write-protected instead of
eagerly split, which is purely a performance issue, not a correctness
issue. But even that is unlikely as it would require userspace pass in a
bitmap where the last page is the only 4K page on a huge page that needs
to be split.
Reported-by: Vipin Sharma <vipinsh@google.com>
Fixes: cb00a70bd4b7 ("KVM: x86/mmu: Split huge pages mapped by the TDP MMU during KVM_CLEAR_DIRTY_LOG")
Signed-off-by: David Matlack <dmatlack@google.com>
Link: https://lore.kernel.org/r/20231027172640.2335197-2-dmatlack@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 59b026b6ad2a..29ac130fcb84 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1392,7 +1392,7 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, gfn_t end = slot->base_gfn + gfn_offset + __fls(mask); if (READ_ONCE(eager_page_split)) - kvm_mmu_try_split_huge_pages(kvm, slot, start, end, PG_LEVEL_4K); + kvm_mmu_try_split_huge_pages(kvm, slot, start, end + 1, PG_LEVEL_4K); kvm_mmu_slot_gfn_write_protect(kvm, slot, start, PG_LEVEL_2M); |