diff options
| author | Sean Christopherson <[email protected]> | 2021-01-13 12:50:30 -0800 |
|---|---|---|
| committer | Paolo Bonzini <[email protected]> | 2021-02-04 05:27:15 -0500 |
| commit | 8fc517267fb28576dfca2380cc2497a2454b8fae (patch) | |
| tree | 01cbf403da58e92d96d3789d81f66ca5ae2d1283 | |
| parent | 15e6a7e5324cc04a67891fc369ea834bbb7e7b42 (diff) | |
KVM: x86: Zap the oldest MMU pages, not the newest
Walk the list of MMU pages in reverse in kvm_mmu_zap_oldest_mmu_pages().
The list is FIFO, meaning new pages are inserted at the head and thus
the oldest pages are at the tail. Using a "forward" iterator causes KVM
to zap MMU pages that were just added, which obliterates guest
performance once the max number of shadow MMU pages is reached.
Fixes: 6b82ef2c9cf1 ("KVM: x86/mmu: Batch zap MMU pages when recycling oldest pages")
Reported-by: Zdenek Kaspar <[email protected]>
Cc: [email protected]
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
| -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 6d16481aa29d..ed861245ecf0 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2417,7 +2417,7 @@ static unsigned long kvm_mmu_zap_oldest_mmu_pages(struct kvm *kvm, return 0; restart: - list_for_each_entry_safe(sp, tmp, &kvm->arch.active_mmu_pages, link) { + list_for_each_entry_safe_reverse(sp, tmp, &kvm->arch.active_mmu_pages, link) { /* * Don't zap active root pages, the page itself can't be freed * and zapping it will just force vCPUs to realloc and reload. |