Commit 37a72b08 authored by Juergen Gross's avatar Juergen Gross Committed by Boris Ostrovsky
Browse files

xen: add "not_essential" flag to struct xenbus_driver 



When booting the xenbus driver will wait for PV devices to have
connected to their backends before continuing. The timeout is different
between essential and non-essential devices.

Non-essential devices are identified by their nodenames directly in the
xenbus driver, which requires to update this list in case a new device
type being non-essential is added (this was missed for several types
in the past).

In order to avoid this problem, add a "not_essential" flag to struct
xenbus_driver which can be set to "true" by the respective frontend.

Set this flag for the frontends currently regarded to be not essential
(vkbs and vfb) and use it for testing in the xenbus driver.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211022064800.14978-2-jgross@suse.com


Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
parent 2a099192

drivers/input/misc/xen-kbdfront.c

+1 −0
Original line number Diff line number Diff line
@@ -542,6 +542,7 @@ static struct xenbus_driver xenkbd_driver = { 
	.remove = xenkbd_remove,

	.resume = xenkbd_resume,

	.otherend_changed = xenkbd_backend_changed,

	.not_essential = true,

};



static int __init xenkbd_init(void)

drivers/video/fbdev/xen-fbfront.c

+1 −0
Original line number Diff line number Diff line
@@ -695,6 +695,7 @@ static struct xenbus_driver xenfb_driver = { 
	.remove = xenfb_remove,

	.resume = xenfb_resume,

	.otherend_changed = xenfb_backend_changed,

	.not_essential = true,

};



static int __init xenfb_init(void)

drivers/xen/xenbus/xenbus_probe_frontend.c

+3 −11
Original line number Diff line number Diff line
@@ -211,19 +211,11 @@ static int is_device_connecting(struct device *dev, void *data, bool ignore_none 
	if (drv && (dev->driver != drv))

		return 0;



	if (ignore_nonessential) {

		/* With older QEMU, for PVonHVM guests the guest config files

		 * could contain: vfb = [ 'vnc=1, vnclisten=0.0.0.0']

		 * which is nonsensical as there is no PV FB (there can be

		 * a PVKB) running as HVM guest. */

	xendrv = to_xenbus_driver(dev->driver);



		if ((strncmp(xendev->nodename, "device/vkbd", 11) == 0))

	if (ignore_nonessential && xendrv->not_essential)

		return 0;



		if ((strncmp(xendev->nodename, "device/vfb", 10) == 0))

			return 0;

	}

	xendrv = to_xenbus_driver(dev->driver);

	return (xendev->state < XenbusStateConnected ||

		(xendev->state == XenbusStateConnected &&

		 xendrv->is_ready && !xendrv->is_ready(xendev)));

include/xen/xenbus.h

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ struct xenbus_driver { 
	const char *name;       /* defaults to ids[0].devicetype */

	const struct xenbus_device_id *ids;

	bool allow_rebind; /* avoid setting xenstore closed during remove */

	bool not_essential;     /* is not mandatory for boot progress */

	int (*probe)(struct xenbus_device *dev,

		     const struct xenbus_device_id *id);

	void (*otherend_changed)(struct xenbus_device *dev,