From nobody Thu Apr 3 10:58:20 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1741126562908709.0378588487254; Tue, 4 Mar 2025 14:16:02 -0800 (PST) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tpaPI-0002Y6-Fe; Tue, 04 Mar 2025 17:06:32 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tpaPG-0002Ko-FN for qemu-devel@nongnu.org; Tue, 04 Mar 2025 17:06:30 -0500 Received: from vps-ovh.mhejs.net ([145.239.82.108]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1tpaPE-0001Mi-OT for qemu-devel@nongnu.org; Tue, 04 Mar 2025 17:06:30 -0500 Received: from MUA by vps-ovh.mhejs.net with esmtpsa (TLS1.3) tls TLS_AES_256_GCM_SHA384 (Exim 4.98) (envelope-from ) id 1tpaPA-00000000LZU-2syA; Tue, 04 Mar 2025 23:06:24 +0100 From: "Maciej S. Szmigiero" To: Peter Xu , Fabiano Rosas Cc: Alex Williamson , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , Eric Blake , Markus Armbruster , =?UTF-8?q?Daniel=20P=20=2E=20Berrang=C3=A9?= , Avihai Horon , Joao Martins , qemu-devel@nongnu.org Subject: [PATCH v6 19/36] vfio/migration: Convert bytes_transferred counter to atomic Date: Tue, 4 Mar 2025 23:03:46 +0100 Message-ID: X-Mailer: git-send-email 2.48.1 In-Reply-To: References: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=145.239.82.108; envelope-from=mhej@vps-ovh.mhejs.net; helo=vps-ovh.mhejs.net X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZM-MESSAGEID: 1741126564393019000 From: "Maciej S. Szmigiero" So it can be safety accessed from multiple threads. This variable type needs to be changed to unsigned long since 32-bit host platforms lack the necessary addition atomics on 64-bit variables. Using 32-bit counters on 32-bit host platforms should not be a problem in practice since they can't realistically address more memory anyway. Reviewed-by: C=C3=A9dric Le Goater Signed-off-by: Maciej S. Szmigiero --- hw/vfio/migration.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c index 03890eaa48a9..5532787be63b 100644 --- a/hw/vfio/migration.c +++ b/hw/vfio/migration.c @@ -55,7 +55,7 @@ */ #define VFIO_MIG_DEFAULT_DATA_BUFFER_SIZE (1 * MiB) =20 -static int64_t bytes_transferred; +static unsigned long bytes_transferred; =20 static const char *mig_state_to_str(enum vfio_device_mig_state state) { @@ -391,7 +391,7 @@ static ssize_t vfio_save_block(QEMUFile *f, VFIOMigrati= on *migration) qemu_put_be64(f, VFIO_MIG_FLAG_DEV_DATA_STATE); qemu_put_be64(f, data_size); qemu_put_buffer(f, migration->data_buffer, data_size); - bytes_transferred +=3D data_size; + qatomic_add(&bytes_transferred, data_size); =20 trace_vfio_save_block(migration->vbasedev->name, data_size); =20 @@ -1013,12 +1013,12 @@ static int vfio_block_migration(VFIODevice *vbasede= v, Error *err, Error **errp) =20 int64_t vfio_mig_bytes_transferred(void) { - return bytes_transferred; + return MIN(qatomic_read(&bytes_transferred), INT64_MAX); } =20 void vfio_reset_bytes_transferred(void) { - bytes_transferred =3D 0; + qatomic_set(&bytes_transferred, 0); } =20 /*