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dkim=none (message not signed) header.d=none;dmarc=pass action=none header.from=nvidia.com; Received-SPF: Pass (protection.outlook.com: domain of nvidia.com designates 216.228.117.160 as permitted sender) receiver=protection.outlook.com; client-ip=216.228.117.160; helo=mail.nvidia.com; pr=C Received: from mail.nvidia.com (216.228.117.160) by BL6PEPF0001AB59.mail.protection.outlook.com (10.167.241.11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9769.17 via Frontend Transport; Tue, 14 Apr 2026 20:07:11 +0000 Received: from rnnvmail201.nvidia.com (10.129.68.8) by mail.nvidia.com (10.129.200.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Tue, 14 Apr 2026 13:06:49 -0700 Received: from meforce.lab.shazbot.org (10.126.230.37) by rnnvmail201.nvidia.com (10.129.68.8) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.20; Tue, 14 Apr 2026 13:06:48 -0700 From: Alex Williamson To: CC: Alex Williamson , , , , , , Subject: [PATCH 1/4] vfio/virtio: Convert list_lock from spinlock to mutex Date: Tue, 14 Apr 2026 14:06:19 -0600 Message-ID: <20260414200625.3601509-2-alex.williamson@nvidia.com> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20260414200625.3601509-1-alex.williamson@nvidia.com> References: <20260414200625.3601509-1-alex.williamson@nvidia.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: rnnvmail203.nvidia.com (10.129.68.9) To rnnvmail201.nvidia.com (10.129.68.8) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: BL6PEPF0001AB59:EE_|CH3PR12MB9730:EE_ X-MS-Office365-Filtering-Correlation-Id: 3408f2ba-227d-45e3-a803-08de9a616a64 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|82310400026|36860700016|1800799024|13003099007|18002099003|56012099003|22082099003; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: PqJcILTR8/1kScY+W0fze3YGh1eac96EER0sNa/QfKdfGAU2fEW48uMI9gHdFcYrXzy3U0DGb8/Qp79C9kV53bAsI5ibBjXFKytf9sW9soPXLLL5WpBssqHxmPoYSMHkPrfpTVuNOl5voJDWSjrEjNfaorqa33QjxmkIYjiWpYWCG56HvN615a1nosbpAg9TM6XFAxRu3ISpGyden0LAGtXvPtV4zTQUG3u5E1IG3MrUBqryzH4y7lE48H0H/zR85v51Lf28y6gXzB0Ojh8wZmqhLzKIIvuSqMje/92m7MWwu6VMRjsQ3pJuvoBgAImNoCfV+S80kK1oVWOYbPNZXvIUslbGsVIMYqJC+jieQKxd7KXJhj8M5+2IUhxURiGdZsk9PammwP6nqMqwmdcR3kJ4WoFaztpatuJcxdT94UsG25bA8SCTyaX4wYVJz53Z X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 14 Apr 2026 20:07:11.8790 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 3408f2ba-227d-45e3-a803-08de9a616a64 X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=43083d15-7273-40c1-b7db-39efd9ccc17a;Ip=[216.228.117.160];Helo=[mail.nvidia.com] X-MS-Exchange-CrossTenant-AuthSource: BL6PEPF0001AB59.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB9730 The list_lock spinlock with IRQ disabling was copied from the mlx5 vfio-pci variant driver, where it is justified by a hardirq async command completion callback that accesses the protected lists. The virtio driver has no such interrupt context usage; all list_lock acquisitions occur in process context via file read/write operations or state transitions under state_mutex. Convert list_lock to a mutex to be consistent with peer vfio-pci variant drivers (hisilicon, pds, qat, xe) which all use mutexes for equivalent migration data protection. This also fixes a mismatched spin_lock()/spin_unlock_irq() pair in virtiovf_read_device_context_chunk() that could incorrectly enable interrupts. Reported-by: Jinhui Guo Closes: https://lore.kernel.org/all/20260413073603.30538-1-guojinhui.liam@bytedance.com Fixes: 0bbc82e4ec79 ("vfio/virtio: Add support for the basic live migration functionality") Cc: stable@vger.kernel.org Assisted-by: Claude:claude-opus-4-6 Signed-off-by: Alex Williamson --- drivers/vfio/pci/virtio/common.h | 2 +- drivers/vfio/pci/virtio/migrate.c | 33 ++++++++++++++++--------------- 2 files changed, 18 insertions(+), 17 deletions(-) diff --git a/drivers/vfio/pci/virtio/common.h b/drivers/vfio/pci/virtio/common.h index cb3d5e57d3a3..3ccbd49e6abe 100644 --- a/drivers/vfio/pci/virtio/common.h +++ b/drivers/vfio/pci/virtio/common.h @@ -68,7 +68,7 @@ struct virtiovf_migration_file { enum virtiovf_migf_state state; enum virtiovf_load_state load_state; /* synchronize access to the lists */ - spinlock_t list_lock; + struct mutex list_lock; struct list_head buf_list; struct list_head avail_list; struct virtiovf_data_buffer *buf; diff --git a/drivers/vfio/pci/virtio/migrate.c b/drivers/vfio/pci/virtio/migrate.c index 35fa2d6ed611..15fcd936528b 100644 --- a/drivers/vfio/pci/virtio/migrate.c +++ b/drivers/vfio/pci/virtio/migrate.c @@ -142,9 +142,9 @@ virtiovf_alloc_data_buffer(struct virtiovf_migration_file *migf, size_t length) static void virtiovf_put_data_buffer(struct virtiovf_data_buffer *buf) { - spin_lock_irq(&buf->migf->list_lock); + mutex_lock(&buf->migf->list_lock); list_add_tail(&buf->buf_elm, &buf->migf->avail_list); - spin_unlock_irq(&buf->migf->list_lock); + mutex_unlock(&buf->migf->list_lock); } static int @@ -170,21 +170,21 @@ virtiovf_get_data_buffer(struct virtiovf_migration_file *migf, size_t length) INIT_LIST_HEAD(&free_list); - spin_lock_irq(&migf->list_lock); + mutex_lock(&migf->list_lock); list_for_each_entry_safe(buf, temp_buf, &migf->avail_list, buf_elm) { list_del_init(&buf->buf_elm); if (buf->allocated_length >= length) { - spin_unlock_irq(&migf->list_lock); + mutex_unlock(&migf->list_lock); goto found; } /* * Prevent holding redundant buffers. Put in a free - * list and call at the end not under the spin lock + * list and call at the end not under the mutex * (&migf->list_lock) to minimize its scope usage. */ list_add(&buf->buf_elm, &free_list); } - spin_unlock_irq(&migf->list_lock); + mutex_unlock(&migf->list_lock); buf = virtiovf_alloc_data_buffer(migf, length); found: @@ -295,6 +295,7 @@ static int virtiovf_release_file(struct inode *inode, struct file *filp) struct virtiovf_migration_file *migf = filp->private_data; virtiovf_disable_fd(migf); + mutex_destroy(&migf->list_lock); mutex_destroy(&migf->lock); kfree(migf); return 0; @@ -308,7 +309,7 @@ virtiovf_get_data_buff_from_pos(struct virtiovf_migration_file *migf, bool found = false; *end_of_data = false; - spin_lock_irq(&migf->list_lock); + mutex_lock(&migf->list_lock); if (list_empty(&migf->buf_list)) { *end_of_data = true; goto end; @@ -329,7 +330,7 @@ virtiovf_get_data_buff_from_pos(struct virtiovf_migration_file *migf, migf->state = VIRTIOVF_MIGF_STATE_ERROR; end: - spin_unlock_irq(&migf->list_lock); + mutex_unlock(&migf->list_lock); return found ? buf : NULL; } @@ -369,10 +370,10 @@ static ssize_t virtiovf_buf_read(struct virtiovf_data_buffer *vhca_buf, } if (*pos >= vhca_buf->start_pos + vhca_buf->length) { - spin_lock_irq(&vhca_buf->migf->list_lock); + mutex_lock(&vhca_buf->migf->list_lock); list_del_init(&vhca_buf->buf_elm); list_add_tail(&vhca_buf->buf_elm, &vhca_buf->migf->avail_list); - spin_unlock_irq(&vhca_buf->migf->list_lock); + mutex_unlock(&vhca_buf->migf->list_lock); } return done; @@ -554,9 +555,9 @@ virtiovf_add_buf_header(struct virtiovf_data_buffer *header_buf, header_buf->length = sizeof(header); header_buf->start_pos = header_buf->migf->max_pos; migf->max_pos += header_buf->length; - spin_lock_irq(&migf->list_lock); + mutex_lock(&migf->list_lock); list_add_tail(&header_buf->buf_elm, &migf->buf_list); - spin_unlock_irq(&migf->list_lock); + mutex_unlock(&migf->list_lock); return 0; } @@ -621,9 +622,9 @@ virtiovf_read_device_context_chunk(struct virtiovf_migration_file *migf, buf->start_pos = buf->migf->max_pos; migf->max_pos += buf->length; - spin_lock(&migf->list_lock); + mutex_lock(&migf->list_lock); list_add_tail(&buf->buf_elm, &migf->buf_list); - spin_unlock_irq(&migf->list_lock); + mutex_unlock(&migf->list_lock); return 0; out_header: @@ -692,7 +693,7 @@ virtiovf_pci_save_device_data(struct virtiovf_pci_core_device *virtvdev, mutex_init(&migf->lock); INIT_LIST_HEAD(&migf->buf_list); INIT_LIST_HEAD(&migf->avail_list); - spin_lock_init(&migf->list_lock); + mutex_init(&migf->list_lock); migf->virtvdev = virtvdev; lockdep_assert_held(&virtvdev->state_mutex); @@ -1082,7 +1083,7 @@ virtiovf_pci_resume_device_data(struct virtiovf_pci_core_device *virtvdev) mutex_init(&migf->lock); INIT_LIST_HEAD(&migf->buf_list); INIT_LIST_HEAD(&migf->avail_list); - spin_lock_init(&migf->list_lock); + mutex_init(&migf->list_lock); buf = virtiovf_alloc_data_buffer(migf, VIRTIOVF_TARGET_INITIAL_BUF_SIZE); if (IS_ERR(buf)) { -- 2.51.0