From patchwork Fri Jun 2 16:09:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vipin Sharma X-Patchwork-Id: 13265616 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 319E3C7EE2E for ; Fri, 2 Jun 2023 16:11:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236039AbjFBQLE (ORCPT ); Fri, 2 Jun 2023 12:11:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236615AbjFBQKv (ORCPT ); Fri, 2 Jun 2023 12:10:51 -0400 Received: from mail-yw1-x1149.google.com (mail-yw1-x1149.google.com [IPv6:2607:f8b0:4864:20::1149]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB6A010D0 for ; Fri, 2 Jun 2023 09:10:06 -0700 (PDT) Received: by mail-yw1-x1149.google.com with SMTP id 00721157ae682-568960f4596so34413587b3.1 for ; Fri, 02 Jun 2023 09:10:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1685722186; x=1688314186; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=iiQKR5r12cEmfxEtqKB501qQ7U5/inaqlNqkSHrg1Dk=; b=pa3mVvglr9ldo0oASWJgWygRLd3hw8lG1pjLeB+Qzm3K3zOU5BQU88aja7wxcgPXwA AwayadZx6shxLAXjuJFrDzlMtsvb67kGNUVBIz8jQ9pcx5Jd6BF7pMABQixgPuk47qo/ QPSMIrvsitPTIbIvBs3Unmlez10KGpvyazPz0vuoWxeM0ddu7MUX6bOpsZv5FX/RHsfI ab0UhQ4BKG9ohwFpekgRN7rsQtHAtMFU2PEbvOsbX5+K7m399sRVLlUcmEJAu36XrUm4 MIK72o4Xoc2dnSjS77GyfH7dzmpmSt4gmenJO3sxGLvRMkP8fiKXjBjSppWa9vRlnGfd FwPA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1685722186; x=1688314186; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=iiQKR5r12cEmfxEtqKB501qQ7U5/inaqlNqkSHrg1Dk=; b=jtQXkU1MRKuAegVwAHYyCZ4hZh9ud6RS3g13lY1DTYmT0iCpKalHGrUyecReQDEFYV ZGvdBthFgIeAS9bf+aeThoO/l/3f3J7jmWaMGgbMJFAn9Ki6Uzcgx/YMEqz0bNw0ic/N 9EeX4yXDxKMrEOaXJ/xdjWFH705kgonC1D7ODLimLlAv61CGzDcgKsTI91CW1ZPP90hi +2ayuA6QLayljLqOFLh1V5V5kT2fpR/GkWRIciDjYnZvOG1aPajLJV9S2xCEGBBxs8MH E4QLRaIKNqc9E3Ixv1jRTZr1vsOmvRClcCEnaI01WGxqlJGBARxlZgnit/YwLBdoY/Nh lmMQ== X-Gm-Message-State: AC+VfDwnuERw7KaEV9EBv2DuzqAMeOw6y2Y/GyGXxbbW9AsH4o51dZrP 5jyHumzaQB0uZAxNljRkN+sYc+Tk0jPX X-Google-Smtp-Source: ACHHUZ4B/VNE5B0Lzqq5kfdIQx5Z2vYuoQBh8/63RZRhZfWL9mTILlGstZ7p9kQje0NOJUJPGy2sE9Fs2xL/ X-Received: from vipin.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:479f]) (user=vipinsh job=sendgmr) by 2002:a05:6902:1545:b0:ba8:181b:2558 with SMTP id r5-20020a056902154500b00ba8181b2558mr2255805ybu.4.1685722186031; Fri, 02 Jun 2023 09:09:46 -0700 (PDT) Date: Fri, 2 Jun 2023 09:09:11 -0700 In-Reply-To: <20230602160914.4011728-1-vipinsh@google.com> Mime-Version: 1.0 References: <20230602160914.4011728-1-vipinsh@google.com> X-Mailer: git-send-email 2.41.0.rc0.172.g3f132b7071-goog Message-ID: <20230602160914.4011728-14-vipinsh@google.com> Subject: [PATCH v2 13/16] KVM: arm64: Run clear-dirty-log under MMU read lock From: Vipin Sharma To: maz@kernel.org, oliver.upton@linux.dev, james.morse@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, chenhuacai@kernel.org, aleksandar.qemu.devel@gmail.com, tsbogend@alpha.franken.de, anup@brainfault.org, atishp@atishpatra.org, paul.walmsley@sifive.com, palmer@dabbelt.com, aou@eecs.berkeley.edu, seanjc@google.com, pbonzini@redhat.com, dmatlack@google.com, ricarkol@google.com Cc: linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-mips@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-kselftest@vger.kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Vipin Sharma Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Take MMU read lock for clearing dirty logs and use shared page table walker. Dirty logs are currently cleared using MMU write locks. This means vCPUs page faults, which takes MMU read lock, will be blocked while dirty logs are being cleared. This causes guest degradation and especially noticeable on VMs with lot of vCPUs. Taking MMU read lock will allow vCPUs to execute parallelly and reduces the impact on vCPUs performance. Signed-off-by: Vipin Sharma --- arch/arm64/kvm/mmu.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 356dc4131023..7c966f6f1a41 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -74,8 +74,12 @@ static int stage2_apply_range(struct kvm_s2_mmu *mmu, phys_addr_t addr, if (ret) break; - if (resched && next != end) - cond_resched_rwlock_write(&kvm->mmu_lock); + if (resched && next != end) { + if (flags & KVM_PGTABLE_WALK_SHARED) + cond_resched_rwlock_read(&kvm->mmu_lock); + else + cond_resched_rwlock_write(&kvm->mmu_lock); + } } while (addr = next, addr != end); return ret; @@ -1131,11 +1135,11 @@ void kvm_arch_mmu_enable_log_dirty_pt_masked(struct kvm *kvm, phys_addr_t start = (base_gfn + __ffs(mask)) << PAGE_SHIFT; phys_addr_t end = (base_gfn + __fls(mask) + 1) << PAGE_SHIFT; - write_lock(&kvm->mmu_lock); - lockdep_assert_held_write(&kvm->mmu_lock); - - stage2_wp_range(&kvm->arch.mmu, start, end, 0); + read_lock(&kvm->mmu_lock); + stage2_wp_range(&kvm->arch.mmu, start, end, KVM_PGTABLE_WALK_SHARED); + read_unlock(&kvm->mmu_lock); + write_lock(&kvm->mmu_lock); /* * Eager-splitting is done when manual-protect is set. We * also check for initially-all-set because we can avoid