From mboxrd@z Thu Jan 1 00:00:00 1970 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 1EFB3C7EE29 for ; Thu, 8 Jun 2023 22:06:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237046AbjFHWGu (ORCPT ); Thu, 8 Jun 2023 18:06:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47298 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236909AbjFHWGr (ORCPT ); Thu, 8 Jun 2023 18:06:47 -0400 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 BB81430D4 for ; Thu, 8 Jun 2023 15:06:39 -0700 (PDT) Received: by mail-pj1-x104a.google.com with SMTP id 98e67ed59e1d1-25b79a5cf1aso78046a91.1 for ; Thu, 08 Jun 2023 15:06:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1686261999; x=1688853999; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=RLQAgYf8iBGNcj/RlWRJvdUP+LxzH+dVMP3y494+MG8=; b=jiucnEhHBHr3c6BmEzMcwGJYY5q/sfwTNMPWWLYqVidMy1ACgG+F4SMLbQC+sxFx8P MgXO/ls1Qh9ojSIi9fREuHQLVDtJVbbXNSGrAHqjqmXunrWoPXQioFgwqITHfRC2RF7S krksZEMjv8T4fZD9ohzoli64PNBHIoR7RtjjXhBKm+ILTUHJIsjF6bBVFHudjFQ43RAJ QjLnUGQxwAWUeWUK76k33+fR9B50+FAd8nHuH4gYW55RNEa1TK7TgaOcSaYfQfQ/yqEU gTerywae+9jvND4TfEQNeVGBNRP4j8FT/9XDIlbTQL9SfcEMzU0DbA+854khObUx4iA2 DkyA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686261999; x=1688853999; 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=RLQAgYf8iBGNcj/RlWRJvdUP+LxzH+dVMP3y494+MG8=; b=X8mmyC9ov26xYev9s/JPtg4vBJlGZqgwpVxRuQUcXU3r/RfYpWpNru+rHTSNXU+LU0 zC9GCUwga42VTu4JmP93WeaUzJgBqyTaZ7ymZl0zMAD2yGCFUkbFWCtVxbfdEGRAXV3i pOAFKZ08oKQubCAdd5y4T99mFdNDhzll7rzrzGYCNHc1agz8fM3M2bI4oChpazu2EXNK 5T+IKa2uTN81YdC3TPcfhxb711JBc51JK5NB+BPt+G419a8PVoQWkuzXHSzmLccmiSFU uiEP8/Kzh3JLLcbpGdIvXr3a84MfTOoQxwVD71GECk4ijmTt8dyD2YHv6+oS5bz1ESoo wYeg== X-Gm-Message-State: AC+VfDzDBdIvrYwLDlavSBjxykDPQ9lHNv0KpPHTAEM/SHDMV7XJhx7u J/vmaHp5EG2SMR+f7xcm/apmppq9oaL+aRrqWiHm5rSfhnWTWJmSAsH2bZTr4g+kEik6lPLO+jR S9o3JfZINN6RBGNi7Z+Q9bGpImw9x9qvUa6kAyGb2ifJoy7q18tYNDSgIJfS0NcWd2msjdQ== X-Google-Smtp-Source: ACHHUZ4BB7wc/3PLgyJlfh6FiXwuAOEqUsspFVK4qOkYedUMSsY2SeUi7aLElhIVZxfm8OeC1VsqR/loduM= X-Received: from colette.c.googlers.com ([fda3:e722:ac3:cc00:24:72f4:c0a8:5cff]) (user=ctshao job=sendgmr) by 2002:a17:90a:7886:b0:253:4800:438b with SMTP id x6-20020a17090a788600b002534800438bmr786194pjk.2.1686261997920; Thu, 08 Jun 2023 15:06:37 -0700 (PDT) Date: Thu, 8 Jun 2023 15:05:41 -0700 In-Reply-To: <20230608220558.39094-1-ctshao@google.com> Mime-Version: 1.0 References: <20230608220558.39094-1-ctshao@google.com> X-Mailer: git-send-email 2.41.0.162.gfafddb0af9-goog Message-ID: <20230608220558.39094-4-ctshao@google.com> Subject: [PATCH v1 3/3] KVM: arm64: Using rcu_read_lock() for kvm_pgtable_stage2_mkyoung() From: Chun-Tse Shao To: linux-kernel@vger.kernel.org, yuzhao@google.com, oliver.upton@linux.dev Cc: Chun-Tse Shao , Marc Zyngier , James Morse , Suzuki K Poulose , Zenghui Yu , Catalin Marinas , Will Deacon , Ben Gardon , Gavin Shan , linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Access bit is RCU safe and can be set without taking kvm->mmu_lock(). Replacing existing kvm->mmu_lock() with rcu_read_lock() for better performance. Original disussion can be found in: https://lore.kernel.org/kvmarm/CAOUHufZrfnfcbrqSzmHkejR5MA2gmGKZ3LMRhbLHV+1427z=Tw@mail.gmail.com/ Suggested-by: Yu Zhao Signed-off-by: Chun-Tse Shao --- arch/arm64/kvm/mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index 3b9d4d24c361..0f7ea66fb894 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1437,10 +1437,10 @@ static void handle_access_fault(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa) trace_kvm_access_fault(fault_ipa); - read_lock(&vcpu->kvm->mmu_lock); + rcu_read_lock(); mmu = vcpu->arch.hw_mmu; pte = kvm_pgtable_stage2_mkyoung(mmu->pgt, fault_ipa); - read_unlock(&vcpu->kvm->mmu_lock); + rcu_read_unlock(); if (kvm_pte_valid(pte)) kvm_set_pfn_accessed(kvm_pte_to_pfn(pte)); -- 2.41.0.162.gfafddb0af9-goog