Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752889AbcCYN3G (ORCPT ); Fri, 25 Mar 2016 09:29:06 -0400 Received: from mga09.intel.com ([134.134.136.24]:65173 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752679AbcCYN3C (ORCPT ); Fri, 25 Mar 2016 09:29:02 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,391,1455004800"; d="scan'208";a="73118604" From: Xiao Guangrong To: pbonzini@redhat.com Cc: gleb@kernel.org, mtosatti@redhat.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Xiao Guangrong Subject: [PATCH 4/4] KVM: MMU: skip obsolete sp in for_each_gfn_*() Date: Fri, 25 Mar 2016 21:19:38 +0800 Message-Id: <1458911978-19430-4-git-send-email-guangrong.xiao@linux.intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1458911978-19430-1-git-send-email-guangrong.xiao@linux.intel.com> References: <1458911978-19430-1-git-send-email-guangrong.xiao@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2895 Lines: 79 The obsolete sp should not be used on current vCPUs and should not hurt vCPU's running, so skip it from for_each_gfn_sp() and for_each_gfn_indirect_valid_sp() The side effort is we will double check role.invalid in kvm_mmu_get_page() but i think it is okay as role is well cached Signed-off-by: Xiao Guangrong --- arch/x86/kvm/mmu.c | 28 ++++++++++++---------------- 1 file changed, 12 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index c396e8b..4d66a9e 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1906,18 +1906,17 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, * since it has been deleted from active_mmu_pages but still can be found * at hast list. * - * for_each_gfn_indirect_valid_sp has skipped that kind of page and - * kvm_mmu_get_page(), the only user of for_each_gfn_sp(), has skipped - * all the obsolete pages. + * for_each_gfn_valid_sp() has skipped that kind of pages. */ -#define for_each_gfn_sp(_kvm, _sp, _gfn) \ +#define for_each_gfn_valid_sp(_kvm, _sp, _gfn) \ hlist_for_each_entry(_sp, \ &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)], hash_link) \ - if ((_sp)->gfn != (_gfn)) {} else + if ((_sp)->gfn != (_gfn) || is_obsolete_sp((_kvm), (_sp)) \ + || (_sp)->role.invalid) {} else #define for_each_gfn_indirect_valid_sp(_kvm, _sp, _gfn) \ - for_each_gfn_sp(_kvm, _sp, _gfn) \ - if ((_sp)->role.direct || (_sp)->role.invalid) {} else + for_each_gfn_valid_sp(_kvm, _sp, _gfn) \ + if ((_sp)->role.direct) {} else /* @sp->gfn should be write-protected at the call site */ static bool __kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, @@ -1958,6 +1957,11 @@ static void kvm_mmu_audit(struct kvm_vcpu *vcpu, int point) { } static void mmu_audit_disable(void) { } #endif +static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp) +{ + return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen); +} + static bool kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, struct list_head *invalid_list) { @@ -2092,11 +2096,6 @@ static void clear_sp_write_flooding_count(u64 *spte) __clear_sp_write_flooding_count(sp); } -static bool is_obsolete_sp(struct kvm *kvm, struct kvm_mmu_page *sp) -{ - return unlikely(sp->mmu_valid_gen != kvm->arch.mmu_valid_gen); -} - static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, gfn_t gfn, gva_t gaddr, @@ -2123,10 +2122,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu, quadrant &= (1 << ((PT32_PT_BITS - PT64_PT_BITS) * level)) - 1; role.quadrant = quadrant; } - for_each_gfn_sp(vcpu->kvm, sp, gfn) { - if (is_obsolete_sp(vcpu->kvm, sp)) - continue; - + for_each_gfn_valid_sp(vcpu->kvm, sp, gfn) { if (!need_sync && sp->unsync) need_sync = true; -- 1.8.3.1