From patchwork Tue Sep 25 17:58:39 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vitaly Kuznetsov X-Patchwork-Id: 10614673 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 431A0913 for ; Tue, 25 Sep 2018 17:59:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3B8A62A3C6 for ; Tue, 25 Sep 2018 17:59:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 300F82A42A; Tue, 25 Sep 2018 17:59:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9BC962A3C6 for ; Tue, 25 Sep 2018 17:59:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727520AbeIZAIF (ORCPT ); Tue, 25 Sep 2018 20:08:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48800 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726163AbeIZAIF (ORCPT ); Tue, 25 Sep 2018 20:08:05 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A3663307D927; Tue, 25 Sep 2018 17:59:25 +0000 (UTC) Received: from vitty.brq.redhat.com (ovpn-204-21.brq.redhat.com [10.40.204.21]) by smtp.corp.redhat.com (Postfix) with ESMTP id 09B2860BE1; Tue, 25 Sep 2018 17:59:22 +0000 (UTC) From: Vitaly Kuznetsov To: kvm@vger.kernel.org Cc: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , Jim Mattson , Liran Alon , Sean Christopherson , linux-kernel@vger.kernel.org Subject: [PATCH v2 4/9] x86/kvm/mmu: introduce guest_mmu Date: Tue, 25 Sep 2018 19:58:39 +0200 Message-Id: <20180925175844.20277-5-vkuznets@redhat.com> In-Reply-To: <20180925175844.20277-1-vkuznets@redhat.com> References: <20180925175844.20277-1-vkuznets@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.48]); Tue, 25 Sep 2018 17:59:25 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP When EPT is used for nested guest we need to re-init MMU as shadow EPT MMU (nested_ept_init_mmu_context() does that). When we return back from L2 to L1 kvm_mmu_reset_context() in nested_vmx_load_cr3() resets MMU back to normal TDP mode. Add a special 'guest_mmu' so we can use separate root caches; the improved hit rate is not very important for single vCPU performance, but it avoids contention on the mmu_lock for many vCPUs. On the nested CPUID benchmark, with 16 vCPUs, an L2->L1->L2 vmexit goes from 42k to 26k cycles. Signed-off-by: Vitaly Kuznetsov Signed-off-by: Paolo Bonzini --- Changes since v1: - drop now unneded local vmx variable in vmx_free_vcpu_nested [Sean Christopherson] --- arch/x86/include/asm/kvm_host.h | 3 +++ arch/x86/kvm/mmu.c | 15 +++++++++++---- arch/x86/kvm/vmx.c | 27 ++++++++++++++++++--------- 3 files changed, 32 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 404c3438827b..a3829869353b 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -539,6 +539,9 @@ struct kvm_vcpu_arch { /* Non-nested MMU for L1 */ struct kvm_mmu root_mmu; + /* L1 MMU when running nested */ + struct kvm_mmu guest_mmu; + /* * Paging state of an L2 guest (used for nested npt) * diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 4491b8894337..96c2a0b3eb53 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -4967,8 +4967,10 @@ EXPORT_SYMBOL_GPL(kvm_mmu_load); void kvm_mmu_unload(struct kvm_vcpu *vcpu) { - kvm_mmu_free_roots(vcpu, vcpu->arch.mmu, KVM_MMU_ROOTS_ALL); - WARN_ON(VALID_PAGE(vcpu->arch.mmu->root_hpa)); + kvm_mmu_free_roots(vcpu, &vcpu->arch.root_mmu, KVM_MMU_ROOTS_ALL); + WARN_ON(VALID_PAGE(vcpu->arch.root_mmu.root_hpa)); + kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL); + WARN_ON(VALID_PAGE(vcpu->arch.guest_mmu.root_hpa)); } EXPORT_SYMBOL_GPL(kvm_mmu_unload); @@ -5407,13 +5409,18 @@ int kvm_mmu_create(struct kvm_vcpu *vcpu) vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; + vcpu->arch.root_mmu.root_hpa = INVALID_PAGE; vcpu->arch.root_mmu.translate_gpa = translate_gpa; - vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa; - for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) vcpu->arch.root_mmu.prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID; + vcpu->arch.guest_mmu.root_hpa = INVALID_PAGE; + vcpu->arch.guest_mmu.translate_gpa = translate_gpa; + for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) + vcpu->arch.guest_mmu.prev_roots[i] = KVM_MMU_ROOT_INFO_INVALID; + + vcpu->arch.nested_mmu.translate_gpa = translate_nested_gpa; return alloc_mmu_pages(vcpu); } diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 2d55adab52de..93ff08136fc1 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -8468,8 +8468,10 @@ static inline void nested_release_vmcs12(struct vcpu_vmx *vmx) * Free whatever needs to be freed from vmx->nested when L1 goes down, or * just stops using VMX. */ -static void free_nested(struct vcpu_vmx *vmx) +static void free_nested(struct kvm_vcpu *vcpu) { + struct vcpu_vmx *vmx = to_vmx(vcpu); + if (!vmx->nested.vmxon && !vmx->nested.smm.vmxon) return; @@ -8502,6 +8504,8 @@ static void free_nested(struct vcpu_vmx *vmx) vmx->nested.pi_desc = NULL; } + kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL); + free_loaded_vmcs(&vmx->nested.vmcs02); } @@ -8510,7 +8514,7 @@ static int handle_vmoff(struct kvm_vcpu *vcpu) { if (!nested_vmx_check_permission(vcpu)) return 1; - free_nested(to_vmx(vcpu)); + free_nested(vcpu); nested_vmx_succeed(vcpu); return kvm_skip_emulated_instruction(vcpu); } @@ -8541,6 +8545,8 @@ static int handle_vmclear(struct kvm_vcpu *vcpu) if (vmptr == vmx->nested.current_vmptr) nested_release_vmcs12(vmx); + kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL); + kvm_vcpu_write_guest(vcpu, vmptr + offsetof(struct vmcs12, launch_state), &zero, sizeof(zero)); @@ -8924,6 +8930,9 @@ static int handle_vmptrld(struct kvm_vcpu *vcpu) } nested_release_vmcs12(vmx); + + kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, + KVM_MMU_ROOTS_ALL); /* * Load VMCS12 from guest memory since it is not already * cached. @@ -10976,12 +10985,10 @@ static void vmx_switch_vmcs(struct kvm_vcpu *vcpu, struct loaded_vmcs *vmcs) */ static void vmx_free_vcpu_nested(struct kvm_vcpu *vcpu) { - struct vcpu_vmx *vmx = to_vmx(vcpu); - - vcpu_load(vcpu); - vmx_switch_vmcs(vcpu, &vmx->vmcs01); - free_nested(vmx); - vcpu_put(vcpu); + vcpu_load(vcpu); + vmx_switch_vmcs(vcpu, &to_vmx(vcpu)->vmcs01); + free_nested(vcpu); + vcpu_put(vcpu); } static void vmx_free_vcpu(struct kvm_vcpu *vcpu) @@ -11331,6 +11338,7 @@ static int nested_ept_init_mmu_context(struct kvm_vcpu *vcpu) if (!valid_ept_address(vcpu, nested_ept_get_cr3(vcpu))) return 1; + vcpu->arch.mmu = &vcpu->arch.guest_mmu; kvm_init_shadow_ept_mmu(vcpu, to_vmx(vcpu)->nested.msrs.ept_caps & VMX_EPT_EXECUTE_ONLY_BIT, @@ -11346,6 +11354,7 @@ static int nested_ept_init_mmu_context(struct kvm_vcpu *vcpu) static void nested_ept_uninit_mmu_context(struct kvm_vcpu *vcpu) { + vcpu->arch.mmu = &vcpu->arch.root_mmu; vcpu->arch.walk_mmu = &vcpu->arch.root_mmu; } @@ -13421,7 +13430,7 @@ static void vmx_leave_nested(struct kvm_vcpu *vcpu) to_vmx(vcpu)->nested.nested_run_pending = 0; nested_vmx_vmexit(vcpu, -1, 0, 0); } - free_nested(to_vmx(vcpu)); + free_nested(vcpu); } /*