From: Filip Hejsek <filip.hejsek@gmail.com>
Date: Mon, 23 Feb 2026 17:37:02 +0000 (+0100)
Subject: virtio_console: read size from config space during device init
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b3592a32b34f37874dc94aa1a0d15c4334ed86ca;p=thirdparty%2Flinux.git

virtio_console: read size from config space during device init

Previously, the size was only read upon receiving the config interrupt.
This interrupt is sent when the size changes. However, we also need to
read the initial size.

Also make sure to only read the size from config if F_SIZE is enabled.

Fixes: 9778829cffd4 ("virtio: console: Store each console's size in the console structure")
Signed-off-by: Filip Hejsek <filip.hejsek@gmail.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Message-ID: <20260223-virtio-console-fix-v1-1-0cf08303b428@gmail.com>
---

diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index 9a33217c68d9..198b97314168 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -1771,32 +1771,40 @@ static void config_intr(struct virtio_device *vdev)
 		schedule_work(&portdev->config_work);
 }
 
-static void config_work_handler(struct work_struct *work)
+static void update_size_from_config(struct ports_device *portdev)
 {
-	struct ports_device *portdev;
+	struct virtio_device *vdev;
+	struct port *port;
+	u16 rows, cols;
 
-	portdev = container_of(work, struct ports_device, config_work);
-	if (!use_multiport(portdev)) {
-		struct virtio_device *vdev;
-		struct port *port;
-		u16 rows, cols;
+	vdev = portdev->vdev;
 
-		vdev = portdev->vdev;
-		virtio_cread(vdev, struct virtio_console_config, cols, &cols);
-		virtio_cread(vdev, struct virtio_console_config, rows, &rows);
+	/*
+	 * We'll use this way of resizing only for legacy support.
+	 * For multiport devices, use control messages to indicate
+	 * console size changes so that it can be done per-port.
+	 *
+	 * Don't test F_SIZE at all if we're rproc: not a valid feature.
+	 */
+	if (is_rproc_serial(vdev) ||
+	    use_multiport(portdev) ||
+	    !virtio_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE))
+		return;
 
-		port = find_port_by_id(portdev, 0);
-		set_console_size(port, rows, cols);
+	virtio_cread(vdev, struct virtio_console_config, cols, &cols);
+	virtio_cread(vdev, struct virtio_console_config, rows, &rows);
 
-		/*
-		 * We'll use this way of resizing only for legacy
-		 * support.  For newer userspace
-		 * (VIRTIO_CONSOLE_F_MULTPORT+), use control messages
-		 * to indicate console size changes so that it can be
-		 * done per-port.
-		 */
-		resize_console(port);
-	}
+	port = find_port_by_id(portdev, 0);
+	set_console_size(port, rows, cols);
+	resize_console(port);
+}
+
+static void config_work_handler(struct work_struct *work)
+{
+	struct ports_device *portdev;
+
+	portdev = container_of(work, struct ports_device, config_work);
+	update_size_from_config(portdev);
 }
 
 static int init_vqs(struct ports_device *portdev)
@@ -2052,6 +2060,8 @@ static int virtcons_probe(struct virtio_device *vdev)
 	__send_control_msg(portdev, VIRTIO_CONSOLE_BAD_ID,
 			   VIRTIO_CONSOLE_DEVICE_READY, 1);
 
+	update_size_from_config(portdev);
+
 	return 0;
 
 free_chrdev: