From patchwork Tue Feb 5 21:01:21 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sean Christopherson X-Patchwork-Id: 10798453 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 5D80C922 for ; Tue, 5 Feb 2019 21:02:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4F5B82C978 for ; Tue, 5 Feb 2019 21:02:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4DF112CA28; Tue, 5 Feb 2019 21:02:50 +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 F01CD2CA0A for ; Tue, 5 Feb 2019 21:02:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729931AbfBEVCs (ORCPT ); Tue, 5 Feb 2019 16:02:48 -0500 Received: from mga07.intel.com ([134.134.136.100]:30420 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729912AbfBEVCr (ORCPT ); Tue, 5 Feb 2019 16:02:47 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 05 Feb 2019 13:02:47 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,336,1544515200"; d="scan'208";a="131343500" Received: from sjchrist-coffee.jf.intel.com ([10.54.74.14]) by FMSMGA003.fm.intel.com with ESMTP; 05 Feb 2019 13:02:46 -0800 From: Sean Christopherson To: Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= Cc: kvm@vger.kernel.org, Xiao Guangrong Subject: [PATCH v2 11/27] KVM: x86/mmu: Zap only the relevant pages when removing a memslot Date: Tue, 5 Feb 2019 13:01:21 -0800 Message-Id: <20190205210137.1377-11-sean.j.christopherson@intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190205205443.1059-1-sean.j.christopherson@intel.com> References: <20190205205443.1059-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Modify kvm_mmu_invalidate_zap_pages_in_memslot(), a.k.a. the x86 MMU's handler for kvm_arch_flush_shadow_memslot(), to zap only the pages/PTEs that actually belong to the memslot being removed. This improves performance, especially why the deleted memslot has only a few shadow entries, or even no entries. E.g. a microbenchmark to access regular memory while concurrently reading PCI ROM to trigger memslot deletion showed a 5% improvement in throughput. Cc: Xiao Guangrong Signed-off-by: Sean Christopherson --- arch/x86/kvm/mmu.c | 33 ++++++++++++++++++++++++++++++++- 1 file changed, 32 insertions(+), 1 deletion(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index b6f362a988fd..ba96bf9cf706 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -5619,7 +5619,38 @@ static void kvm_mmu_invalidate_zap_pages_in_memslot(struct kvm *kvm, struct kvm_memory_slot *slot, struct kvm_page_track_notifier_node *node) { - kvm_mmu_invalidate_zap_all_pages(kvm); + struct kvm_mmu_page *sp; + LIST_HEAD(invalid_list); + unsigned long i; + bool flush; + gfn_t gfn; + + spin_lock(&kvm->mmu_lock); + + if (list_empty(&kvm->arch.active_mmu_pages)) + goto out_unlock; + + flush = slot_handle_all_level(kvm, slot, kvm_zap_rmapp, false); + + for (i = 0; i < slot->npages; i++) { + gfn = slot->base_gfn + i; + + for_each_valid_sp(kvm, sp, gfn) { + if (sp->gfn != gfn) + continue; + + kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list); + } + if (need_resched() || spin_needbreak(&kvm->mmu_lock)) { + kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush); + flush = false; + cond_resched_lock(&kvm->mmu_lock); + } + } + kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush); + +out_unlock: + spin_unlock(&kvm->mmu_lock); } void kvm_mmu_init_vm(struct kvm *kvm)