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authorXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>2013-05-31 04:36:22 +0400
committerGleb Natapov <gleb@redhat.com>2013-06-05 13:32:33 +0400
commit5304b8d37c2a5ebca48330f5e7868d240eafbed1 (patch)
treeca8df12267cf394c2cb871b7c3ebd742902a55fb /arch/x86/kvm/mmu.h
parenta2ae162265e88bf5490ce54fd5f2d430d6d992b7 (diff)
downloadlinux-5304b8d37c2a5ebca48330f5e7868d240eafbed1.tar.xz
KVM: MMU: fast invalidate all pages
The current kvm_mmu_zap_all is really slow - it is holding mmu-lock to walk and zap all shadow pages one by one, also it need to zap all guest page's rmap and all shadow page's parent spte list. Particularly, things become worse if guest uses more memory or vcpus. It is not good for scalability In this patch, we introduce a faster way to invalidate all shadow pages. KVM maintains a global mmu invalid generation-number which is stored in kvm->arch.mmu_valid_gen and every shadow page stores the current global generation-number into sp->mmu_valid_gen when it is created When KVM need zap all shadow pages sptes, it just simply increase the global generation-number then reload root shadow pages on all vcpus. Vcpu will create a new shadow page table according to current kvm's generation-number. It ensures the old pages are not used any more. Then the obsolete pages (sp->mmu_valid_gen != kvm->arch.mmu_valid_gen) are zapped by using lock-break technique Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com> Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Gleb Natapov <gleb@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu.h')
-rw-r--r--arch/x86/kvm/mmu.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 2adcbc2cac6d..922bfae77c58 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -97,4 +97,5 @@ static inline bool permission_fault(struct kvm_mmu *mmu, unsigned pte_access,
return (mmu->permissions[pfec >> 1] >> pte_access) & 1;
}
+void kvm_mmu_invalidate_zap_all_pages(struct kvm *kvm);
#endif