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: 13265604 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 3BF90C7EE24 for ; Fri, 2 Jun 2023 16:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236859AbjFBQLD (ORCPT ); Fri, 2 Jun 2023 12:11:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36076 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235547AbjFBQKs (ORCPT ); Fri, 2 Jun 2023 12:10:48 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF48410CB for ; Fri, 2 Jun 2023 09:10:05 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-babb7aaa605so3247954276.3 for ; Fri, 02 Jun 2023 09:10:05 -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=ADh2U1ayUMZ8IV5NrM4H5E1gdGIV6PiOPfrBZzinXI76w3imR1hL0DusKTi7UJzFEL FPxGDkq5O14XDMkZ8hkn2nWAq+tQCqGppLq8ch7bTHFholLafCvrFQoIcZGV3K+tpqeL lgSoenQnzH1VwasbG8yLSmCZy0cpoKh62Nlg8WrlNhZ/ocdY6AT6J6K8S3NmdYtASz4j 03btPamfAGZ6DSKJYUdxGiqlaWGTAw4NX2/E0RR8Gubni8PJ5p/my2eLpWBHvGWK03sv 4pvsSk5X/BHazP0THL3tkPVZoCBfNlAxETRigWkoJi22Jm6aVaoAGSY9YqrOZCdiyrsp nzLA== X-Gm-Message-State: AC+VfDxkhOdM6iONtzcnNaqXd4/b4VMaJCxVZkJFOIYCjgG5hPer1lo9 /7wjtjP5btBLSk/GyjCVVEmeyxQU4063 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: linux-mips@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