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xen: add "not_essential" flag to struct xenbus_driver

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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: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20211022064800.14978-2-jgross@suse.com
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
This commit is contained in:
Juergen Gross 2021-10-22 08:47:56 +02:00 committed by Boris Ostrovsky
parent 2a0991929a
commit 37a72b08a3
4 changed files with 7 additions and 12 deletions
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1
drivers/input/misc/xen-kbdfront.c
View File

@ -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)

1
drivers/video/fbdev/xen-fbfront.c
View File

@ -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)

16
drivers/xen/xenbus/xenbus_probe_frontend.c
View File

@ -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. */
if ((strncmp(xendev->nodename, "device/vkbd", 11) == 0))
return 0;
if ((strncmp(xendev->nodename, "device/vfb", 10) == 0))
return 0;
}
xendrv = to_xenbus_driver(dev->driver);
if (ignore_nonessential && xendrv->not_essential)
return 0;
return (xendev->state < XenbusStateConnected ||
(xendev->state == XenbusStateConnected &&
xendrv->is_ready && !xendrv->is_ready(xendev)));

1
include/xen/xenbus.h
View File

@ -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,