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| author | Sean Christopherson <sean.j.christopherson@intel.com> | 2019-02-05 13:01:21 -0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-02-20 22:48:39 +0100 |
| commit | 4e103134b862314dc2f2f18f2fb0ab972adc3f5f (patch) | |
| tree | dccc458d31608d0d922d8af8265bdf938dc35e23 /arch/x86 | |
| parent | a21136345cb6f1a5b7f576701b6a454da5b6e606 (diff) | |
| download | linux-0-day-4e103134b862314dc2f2f18f2fb0ab972adc3f5f.tar.gz linux-0-day-4e103134b862314dc2f2f18f2fb0ab972adc3f5f.tar.xz | |
KVM: x86/mmu: Zap only the relevant pages when removing a memslot
Modify kvm_mmu_invalidate_zap_pages_in_memslot(), a.k.a. the x86 MMU's
handler for kvm_arch_flush_shadow_memslot(), to zap only the pages/PTEs
that actually belong to the memslot being removed. This improves
performance, especially why the deleted memslot has only a few shadow
entries, or even no entries. E.g. a microbenchmark to access regular
memory while concurrently reading PCI ROM to trigger memslot deletion
showed a 5% improvement in throughput.
Cc: Xiao Guangrong <guangrong.xiao@gmail.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 1cce120f06ae0..b81e2cad0237a 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5622,7 +5622,38 @@ static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, struct kvm_page_track_notifier_node *node) { - kvm_mmu_invalidate_zap_all_pages(kvm); + struct kvm_mmu_page *sp; + LIST_HEAD(invalid_list); + unsigned long i; + bool flush; + gfn_t gfn; + + spin_lock(&kvm->mmu_lock); + + if (list_empty(&kvm->arch.active_mmu_pages)) + goto out_unlock; + + flush = slot_handle_all_level(kvm, slot, kvm_zap_rmapp, false); + + for (i = 0; i < slot->npages; i++) { + gfn = slot->base_gfn + i; + + for_each_valid_sp(kvm, sp, gfn) { + if (sp->gfn != gfn) + continue; + + kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); + } + if (need_resched() || spin_needbreak(&kvm->mmu_lock)) { + kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush); + flush = false; + cond_resched_lock(&kvm->mmu_lock); + } + } + kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush); + +out_unlock: + spin_unlock(&kvm->mmu_lock); } void kvm_mmu_init_vm(struct kvm *kvm) |