From patchwork Wed Nov 10 22:29:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Gardon X-Patchwork-Id: 12613431 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 18B9AC433EF for ; Wed, 10 Nov 2021 22:30:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id ECFFB61186 for ; Wed, 10 Nov 2021 22:30:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233703AbhKJWdE (ORCPT ); Wed, 10 Nov 2021 17:33:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38896 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233569AbhKJWdD (ORCPT ); Wed, 10 Nov 2021 17:33:03 -0500 Received: from mail-pj1-x104a.google.com (mail-pj1-x104a.google.com [IPv6:2607:f8b0:4864:20::104a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86EEBC061766 for ; Wed, 10 Nov 2021 14:30:15 -0800 (PST) Received: by mail-pj1-x104a.google.com with SMTP id x1-20020a17090a294100b001a6e7ba6b4eso1804157pjf.9 for ; Wed, 10 Nov 2021 14:30:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=date:message-id:mime-version:subject:from:to:cc; bh=ySCPE8NAX1lRNmXxmGQ5E/m3CVpAu99HXBKNvXv9kkM=; b=LTg73mxCDpv/bUa367hpKKQTs8+f020jMdII0VJpFbsREwildaLz4hxe6678FTiu7h md41/Lb9SO1bRb4M0WDT8Eda86oOjpWByBQr53u52ukVh582EmpvBlaT5toa4QaOy2x4 OTuxdblS/TiiXBwYTkpGQGbZ8oMqUI+12GM3jqVU3Mg7oYYRClUHzWjOqjfSpvBLaVq5 Tv0g9mUDLIf4kvP7KsmitBk8DEWVimHAEGYKfbKya1ExDOOCiXO9O1N0E5aIaNhBaL4M V3nFIPcv2/N4a4+FYrRPAIWLCFyfl1Gjnv3KSVQDKqSRIV6yA35cBhROaTH5fAn4bH53 V3YA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=ySCPE8NAX1lRNmXxmGQ5E/m3CVpAu99HXBKNvXv9kkM=; b=1ZpsbIvOpq0+KkcC374NkO4wKPbZWLOoqSQvkTlREvfuODbO5j614c7Zc3cewn1uGI yugyVxS0V7wXpyr5eHx0MMXmryRrnkmUWsA1PsS1NnzjaB5DwPmpL9knlSx8FBylcuP2 eaB+M036XlBCwxnQGoCnmgS1ll4xVsoVjZGdUkIqRjrz0tzH26YxrqH4BLg4//RZ3jYe A57ZVcluMpF35ZrgX+6Sulg3+tsv+4DJDMhF9Fxtjvwgelm075UDi/ydfPTR/ycBf8mf /RkfaKQIJOJdKbWQgp9HN5tf5LTNMNBqfOjJEQiUEqiq4UmD+O0yo2eZDtbyNsqnf78i Zv+g== X-Gm-Message-State: AOAM5306e/PaJjE6fsYZE6Iai6eknddTp/HhA3s0DNSOi1brxJKaOY05 tb7rIRwkC9tp0fwZijpaneu2B0QKQQX6 X-Google-Smtp-Source: ABdhPJzZ+0cyrVw2fijQ8nnmwqZWeRr/iTDWlvwZ+Oau0OvBfck4jGr2gNprTC4fvjJSYNCrO74pcvpKhUNo X-Received: from bgardon.sea.corp.google.com ([2620:15c:100:202:6586:7b2f:b259:2011]) (user=bgardon job=sendgmr) by 2002:a63:5642:: with SMTP id g2mr1548108pgm.152.1636583415047; Wed, 10 Nov 2021 14:30:15 -0800 (PST) Date: Wed, 10 Nov 2021 14:29:51 -0800 Message-Id: <20211110223010.1392399-1-bgardon@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.34.0.rc0.344.g81b53c2807-goog Subject: [RFC 00/19] KVM: x86/mmu: Optimize disabling dirty logging From: Ben Gardon To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Paolo Bonzini , Peter Xu , Sean Christopherson , Peter Shier , David Matlack , Mingwei Zhang , Yulei Zhang , Wanpeng Li , Xiao Guangrong , Kai Huang , Keqian Zhu , David Hildenbrand , Ben Gardon Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Currently disabling dirty logging with the TDP MMU is extremely slow. On a 96 vCPU / 96G VM it takes ~45 seconds to disable dirty logging with the TDP MMU, as opposed to ~3.5 seconds with the legacy MMU. This series optimizes TLB flushes and introduces in-place large page promotion, to bring the disable dirty log time down to ~2 seconds. Testing: Ran KVM selftests and kvm-unit-tests on an Intel Skylake. This series introduced no new failures. Performance: To collect these results I needed to apply Mingwei's patch "selftests: KVM: align guest physical memory base address to 1GB" https://lkml.org/lkml/2021/8/29/310 David Matlack is going to send out an updated version of that patch soon. Without this series, TDP MMU: > ./dirty_log_perf_test -v 96 -s anonymous_hugetlb_1gb Test iterations: 2 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory offset: 0x3fe7c0000000 Populate memory time: 10.966500447s Enabling dirty logging time: 0.002068737s Iteration 1 dirty memory time: 0.047556280s Iteration 1 get dirty log time: 0.001253914s Iteration 1 clear dirty log time: 0.049716661s Iteration 2 dirty memory time: 3.679662016s Iteration 2 get dirty log time: 0.000659546s Iteration 2 clear dirty log time: 1.834329322s Disabling dirty logging time: 45.738439510s Get dirty log over 2 iterations took 0.001913460s. (Avg 0.000956730s/iteration) Clear dirty log over 2 iterations took 1.884045983s. (Avg 0.942022991s/iteration) Without this series, Legacy MMU: > ./dirty_log_perf_test -v 96 -s anonymous_hugetlb_1gb Test iterations: 2 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory offset: 0x3fe7c0000000 Populate memory time: 12.664750666s Enabling dirty logging time: 0.002025510s Iteration 1 dirty memory time: 0.046240875s Iteration 1 get dirty log time: 0.001864342s Iteration 1 clear dirty log time: 0.170243637s Iteration 2 dirty memory time: 31.571088701s Iteration 2 get dirty log time: 0.000626245s Iteration 2 clear dirty log time: 1.294817729s Disabling dirty logging time: 3.566831573s Get dirty log over 2 iterations took 0.002490587s. (Avg 0.001245293s/iteration) Clear dirty log over 2 iterations took 1.465061366s. (Avg 0.732530683s/iteration) With this series, TDP MMU: > ./dirty_log_perf_test -v 96 -s anonymous_hugetlb_1gb Test iterations: 2 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory offset: 0x3fe7c0000000 Populate memory time: 12.016653537s Enabling dirty logging time: 0.001992860s Iteration 1 dirty memory time: 0.046701599s Iteration 1 get dirty log time: 0.001214806s Iteration 1 clear dirty log time: 0.049519923s Iteration 2 dirty memory time: 3.581931268s Iteration 2 get dirty log time: 0.000621383s Iteration 2 clear dirty log time: 1.894597059s Disabling dirty logging time: 1.950542092s Get dirty log over 2 iterations took 0.001836189s. (Avg 0.000918094s/iteration) Clear dirty log over 2 iterations took 1.944116982s. (Avg 0.972058491s/iteration) Patch breakdown: Patch 1 is a fix for a bug in the way the TBP MMU issues TLB flushes Patches 2-5 eliminate many unnecessary TLB flushes through better batching Patches 6-12 remove the need for a vCPU pointer to make_spte Patches 13-18 are small refactors in perparation for patch 19 Patch 19 implements in-place largepage promotion when disabling dirty logging Ben Gardon (19): KVM: x86/mmu: Fix TLB flush range when handling disconnected pt KVM: x86/mmu: Batch TLB flushes for a single zap KVM: x86/mmu: Factor flush and free up when zapping under MMU write lock KVM: x86/mmu: Yield while processing disconnected_sps KVM: x86/mmu: Remove redundant flushes when disabling dirty logging KVM: x86/mmu: Introduce vcpu_make_spte KVM: x86/mmu: Factor wrprot for nested PML out of make_spte KVM: x86/mmu: Factor mt_mask out of make_spte KVM: x86/mmu: Remove need for a vcpu from kvm_slot_page_track_is_active KVM: x86/mmu: Remove need for a vcpu from mmu_try_to_unsync_pages KVM: x86/mmu: Factor shadow_zero_check out of make_spte KVM: x86/mmu: Replace vcpu argument with kvm pointer in make_spte KVM: x86/mmu: Factor out the meat of reset_tdp_shadow_zero_bits_mask KVM: x86/mmu: Propagate memslot const qualifier KVM: x86/MMU: Refactor vmx_get_mt_mask KVM: x86/mmu: Factor out part of vmx_get_mt_mask which does not depend on vcpu KVM: x86/mmu: Add try_get_mt_mask to x86_ops KVM: x86/mmu: Make kvm_is_mmio_pfn usable outside of spte.c KVM: x86/mmu: Promote pages in-place when disabling dirty logging arch/x86/include/asm/kvm-x86-ops.h | 1 + arch/x86/include/asm/kvm_host.h | 2 + arch/x86/include/asm/kvm_page_track.h | 6 +- arch/x86/kvm/mmu/mmu.c | 45 +++--- arch/x86/kvm/mmu/mmu_internal.h | 6 +- arch/x86/kvm/mmu/page_track.c | 8 +- arch/x86/kvm/mmu/paging_tmpl.h | 6 +- arch/x86/kvm/mmu/spte.c | 43 +++-- arch/x86/kvm/mmu/spte.h | 17 +- arch/x86/kvm/mmu/tdp_mmu.c | 217 +++++++++++++++++++++----- arch/x86/kvm/mmu/tdp_mmu.h | 5 +- arch/x86/kvm/svm/svm.c | 8 + arch/x86/kvm/vmx/vmx.c | 40 +++-- include/linux/kvm_host.h | 10 +- virt/kvm/kvm_main.c | 12 +- 15 files changed, 302 insertions(+), 124 deletions(-)