From patchwork Tue Sep 16 10:42:02 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: tangchen X-Patchwork-Id: 4916111 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id D35ABBEEA5 for ; Tue, 16 Sep 2014 10:41:25 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 95FCC20121 for ; Tue, 16 Sep 2014 10:41:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B6105201BF for ; Tue, 16 Sep 2014 10:41:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753766AbaIPKkx (ORCPT ); Tue, 16 Sep 2014 06:40:53 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:58727 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753729AbaIPKkv (ORCPT ); Tue, 16 Sep 2014 06:40:51 -0400 X-IronPort-AV: E=Sophos;i="5.04,534,1406563200"; d="scan'208";a="36022268" Received: from localhost (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 16 Sep 2014 18:37:51 +0800 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id s8GAetwG010809; Tue, 16 Sep 2014 18:40:55 +0800 Received: from tangchen.fnst.cn.fujitsu.com (10.167.226.71) by G08CNEXCHPEKD02.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.181.6; Tue, 16 Sep 2014 18:40:51 +0800 From: Tang Chen To: , , , , CC: , , , , , Subject: [PATCH v6 6/6] kvm, mem-hotplug: Unpin and remove kvm_arch->apic_access_page. Date: Tue, 16 Sep 2014 18:42:02 +0800 Message-ID: <1410864122-12434-7-git-send-email-tangchen@cn.fujitsu.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1410864122-12434-1-git-send-email-tangchen@cn.fujitsu.com> References: <1410864122-12434-1-git-send-email-tangchen@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.71] Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.6 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP To make apic access page migratable, we do not pin it in memory now. When it is migrated, we should reload its physical address for all vmcses. But when we tried to do this, all vcpu will access kvm_arch->apic_access_page without any locking. This is not safe. Actually, we do not need kvm_arch->apic_access_page anymore. Since apic access page is not pinned in memory now, we can remove kvm_arch->apic_access_page. When we need to write its physical address into vmcs, use gfn_to_page() to get its page struct, which will also pin it. And unpin it after then. Suggested-by: Gleb Natapov Signed-off-by: Tang Chen --- arch/x86/include/asm/kvm_host.h | 2 +- arch/x86/kvm/vmx.c | 15 +++++++++------ arch/x86/kvm/x86.c | 15 +++++++++------ 3 files changed, 19 insertions(+), 13 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 92b3e72..9daf754 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -576,7 +576,7 @@ struct kvm_arch { struct kvm_apic_map *apic_map; unsigned int tss_addr; - struct page *apic_access_page; + bool apic_access_page_done; gpa_t wall_clock; diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index d0d5981..61f3854 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -4002,7 +4002,7 @@ static int alloc_apic_access_page(struct kvm *kvm) int r = 0; mutex_lock(&kvm->slots_lock); - if (kvm->arch.apic_access_page) + if (kvm->arch.apic_access_page_done) goto out; kvm_userspace_mem.slot = APIC_ACCESS_PAGE_PRIVATE_MEMSLOT; kvm_userspace_mem.flags = 0; @@ -4018,7 +4018,12 @@ static int alloc_apic_access_page(struct kvm *kvm) goto out; } - kvm->arch.apic_access_page = page; + /* + * Do not pin apic access page in memory so that memory hotplug + * process is able to migrate it. + */ + put_page(page); + kvm->arch.apic_access_page_done = true; out: mutex_unlock(&kvm->slots_lock); return r; @@ -4534,8 +4539,7 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu) } if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) - vmcs_write64(APIC_ACCESS_ADDR, - page_to_phys(vmx->vcpu.kvm->arch.apic_access_page)); + kvm_vcpu_reload_apic_access_page(vcpu); if (vmx_vm_has_apicv(vcpu->kvm)) memset(&vmx->pi_desc, 0, sizeof(struct pi_desc)); @@ -7995,8 +7999,7 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) } else if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) { exec_control |= SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES; - vmcs_write64(APIC_ACCESS_ADDR, - page_to_phys(vcpu->kvm->arch.apic_access_page)); + kvm_vcpu_reload_apic_access_page(vcpu); } vmcs_write32(SECONDARY_VM_EXEC_CONTROL, exec_control); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 3f458b2..9094e13 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5991,15 +5991,20 @@ static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu) void kvm_vcpu_reload_apic_access_page(struct kvm_vcpu *vcpu) { + struct page *page; + /* * apic access page could be migrated. When the page is being migrated, * GUP will wait till the migrate entry is replaced with the new pte * entry pointing to the new page. */ - vcpu->kvm->arch.apic_access_page = gfn_to_page(vcpu->kvm, - APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT); - kvm_x86_ops->set_apic_access_page_addr(vcpu->kvm, - page_to_phys(vcpu->kvm->arch.apic_access_page)); + page = gfn_to_page(vcpu->kvm, APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT); + kvm_x86_ops->set_apic_access_page_addr(vcpu->kvm, page_to_phys(page)); + /* + * Do not pin apic access page in memory so that memory hotplug + * process is able to migrate it. + */ + put_page(page); } EXPORT_SYMBOL_GPL(kvm_vcpu_reload_apic_access_page); @@ -7253,8 +7258,6 @@ void kvm_arch_destroy_vm(struct kvm *kvm) kfree(kvm->arch.vpic); kfree(kvm->arch.vioapic); kvm_free_vcpus(kvm); - if (kvm->arch.apic_access_page) - put_page(kvm->arch.apic_access_page); kfree(rcu_dereference_check(kvm->arch.apic_map, 1)); }