diff options
| author |   Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> | 2011-05-15 23:20:27 +0800 |
|---|---|---|
| committer |   Avi Kivity <avi@redhat.com> | 2011-07-12 11:45:02 +0300 |
| commit | 332b207d65c1d7982489dbb83e5071c95e19eb75 (patch) | |
| tree | 5a9917fc3b03b6f1c9d9e1436c89c3bc5f45b636 | |
| parent | KVM: VMX: always_inline VMREADs (diff) | |
| download | linux-dev-332b207d65c1d7982489dbb83e5071c95e19eb75.tar.xz linux-dev-332b207d65c1d7982489dbb83e5071c95e19eb75.zip | |
KVM: MMU: optimize pte write path if don't have protected sp
Simply return from kvm_mmu_pte_write path if no shadow page is
write-protected, then we can avoid to walk all shadow pages and hold
mmu-lock
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 1 | ||||
| -rw-r--r-- | arch/x86/kvm/mmu.c | 9 |
2 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index db4b6543b830..387780eb97bb 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -441,6 +441,7 @@ struct kvm_arch { unsigned int n_used_mmu_pages; unsigned int n_requested_mmu_pages; unsigned int n_max_mmu_pages; + unsigned int indirect_shadow_pages; atomic_t invlpg_counter; struct hlist_head mmu_page_hash[KVM_NUM_MMU_PAGES]; /* diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index aee38623b768..b4ae7afa6b3b 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -498,6 +498,7 @@ static void account_shadowed(struct kvm *kvm, gfn_t gfn) linfo = lpage_info_slot(gfn, slot, i); linfo->write_count += 1; } + kvm->arch.indirect_shadow_pages++; } static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn) @@ -513,6 +514,7 @@ static void unaccount_shadowed(struct kvm *kvm, gfn_t gfn) linfo->write_count -= 1; WARN_ON(linfo->write_count < 0); } + kvm->arch.indirect_shadow_pages--; } static int has_wrprotected_page(struct kvm *kvm, @@ -3233,6 +3235,13 @@ void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa, int level, npte, invlpg_counter, r, flooded = 0; bool remote_flush, local_flush, zap_page; + /* + * If we don't have indirect shadow pages, it means no page is + * write-protected, so we can exit simply. + */ + if (!ACCESS_ONCE(vcpu->kvm->arch.indirect_shadow_pages)) + return; + zap_page = remote_flush = local_flush = false; offset = offset_in_page(gpa); |