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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9F659ECAAA3 for ; Fri, 26 Aug 2022 11:20:10 +0000 (UTC) Received: from localhost ([::1]:39266 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oRXNh-0001F4-8o for qemu-devel@archiver.kernel.org; Fri, 26 Aug 2022 07:20:09 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:43600) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oRX4s-0008GS-KG for qemu-devel@nongnu.org; Fri, 26 Aug 2022 07:00:49 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:49361) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oRX4m-0002AW-Vc for qemu-devel@nongnu.org; Fri, 26 Aug 2022 07:00:40 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1661511634; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=WInGbJIK/LxgFJYTQ9+yP9omIG6ujCCLe3ETTNob4Jw=; b=DOF5jnQyVqZQpbtrp54+9tczb1vIjTXoKKZpaGPoKvVFEQbZWH8ui1wCMV75eSjL//oO0F Y7pX7NOpKhhyLNMPltIaSv/xsy3OOadvEhvGIlAQP49jw2NMplu0hq3kwigwxGNhLgDzlh v+/xz4SjqXyEZ5nD2ewjKt2oaw8Cots= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-576-tnYUY0q2PgScATEBfye7MA-1; Fri, 26 Aug 2022 07:00:32 -0400 X-MC-Unique: tnYUY0q2PgScATEBfye7MA-1 Received: by mail-ed1-f69.google.com with SMTP id y14-20020a056402440e00b0044301c7ccd9so889689eda.19 for ; Fri, 26 Aug 2022 04:00:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc; bh=WInGbJIK/LxgFJYTQ9+yP9omIG6ujCCLe3ETTNob4Jw=; b=Uo0mL3+/wJBYrM+AyQI7s2plYKMqcYoEJDErGQ+pDG/JG/gA8uJRLTGfqB65pNdcOq EU2Z8gDKlrKnqUBgHMb49rmk05YR7PMsn5gLFwpDRLYTAYR3UJ99uP30Rc2smqKP5XPj J0thazQgNuHcDdfnqK7AspRjuPIadmjVPaKO4w7+9ur4rWa2T2cVAu/t7jOEGJPNLAq1 Grs+cnrmlqOKYswoqN9UfQpO3WERt9XiNHlBIu5zG5XPbVYEhD2guUaGnQqfpOFIKP88 PQhF0aF2tHymxNlKSNtmEGTEPZaEDIGtt5QshoNyTlpCgIPr5kWW1hRPj/Ragdo71WRN sTMg== X-Gm-Message-State: ACgBeo39h4t/MoPyFcQ2V41NDXbYqQhczqrADLlSlZaoiDLtnwCtbh/E R/stvpdwZ+lX3zK1x2iNxk8kk3KshltsXAflP5MDyif2OfptLS/O8SeR4CNQ/UPCVckxgzTONnz WuwxyFRc19KIqfHqab/Ny3EXV4CJp1zTxHM8zjsmNkKGKkJ0J8WdwHvh3cIH7huj8hyg= X-Received: by 2002:a17:907:7202:b0:73d:6478:5ba5 with SMTP id dr2-20020a170907720200b0073d64785ba5mr5144684ejc.640.1661511631257; Fri, 26 Aug 2022 04:00:31 -0700 (PDT) X-Google-Smtp-Source: AA6agR7ukjxK7zbEStC1RaP+z3W1OcdycaKp5XVFq+gVrLjTJSIgli1jMlOF+8nJIyu2MzzDrkJ1EQ== X-Received: by 2002:a17:907:7202:b0:73d:6478:5ba5 with SMTP id dr2-20020a170907720200b0073d64785ba5mr5144663ejc.640.1661511630923; Fri, 26 Aug 2022 04:00:30 -0700 (PDT) Received: from goa-sendmail ([93.56.160.208]) by smtp.gmail.com with ESMTPSA id v23-20020aa7cd57000000b0043a61f6c389sm1131751edw.4.2022.08.26.04.00.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Aug 2022 04:00:30 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: Peter Xu , Gavin Shan Subject: [PATCH] KVM: dirty ring: add missing memory barrier Date: Fri, 26 Aug 2022 13:00:29 +0200 Message-Id: <20220826110029.59382-1-pbonzini@redhat.com> X-Mailer: git-send-email 2.37.1 MIME-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The KVM_DIRTY_GFN_F_DIRTY flag ensures that the entry is valid. If the read of the fields are not ordered after the read of the flag, QEMU might see stale values. Cc: Peter Xu Cc: Gavin Shan Signed-off-by: Paolo Bonzini --- accel/kvm/kvm-all.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c index 8d81ab74de..f49643cd24 100644 --- a/accel/kvm/kvm-all.c +++ b/accel/kvm/kvm-all.c @@ -719,7 +719,7 @@ static void kvm_dirty_ring_mark_page(KVMState *s, uint32_t as_id, static bool dirty_gfn_is_dirtied(struct kvm_dirty_gfn *gfn) { - return gfn->flags == KVM_DIRTY_GFN_F_DIRTY; + return qatomic_load_acquire(&gfn->flags, KVM_DIRTY_GFN_F_DIRTY); } static void dirty_gfn_set_collected(struct kvm_dirty_gfn *gfn) -- 2.37.1