[PATCH 6.18 069/752] xenbus: Use .freeze/.thaw to handle xenbus devices

Sasha Levin
2026-02-28T17:49:06Z

From: Jason Andryuk <jason.andryuk@amd.com>

[ Upstream commit e08dd1ee49838750a514e83c0aa60cd12ba6ecbb ]

The goal is to fix s2idle and S3 for Xen PV devices. A domain resuming
from s3 or s2idle disconnects its PV devices during resume. The
backends are not expecting this and do not reconnect.

b3e96c0c7562 ("xen: use freeze/restore/thaw PM events for suspend/
resume/chkpt") changed xen_suspend()/do_suspend() from
PMSG_SUSPEND/PMSG_RESUME to PMSG_FREEZE/PMSG_THAW/PMSG_RESTORE, but the
suspend/resume callbacks remained.

.freeze/restore are used with hiberation where Linux restarts in a new
place in the future. .suspend/resume are useful for runtime power
management for the duration of a boot.

The current behavior of the callbacks works for an xl save/restore or
live migration where the domain is restored/migrated to a new location
and connecting to a not-already-connected backend.

Change xenbus_pm_ops to use .freeze/thaw/restore and drop the
.suspend/resume hook. This matches the use in drivers/xen/manage.c for
save/restore and live migration. With .suspend/resume empty, PV devices
are left connected during s2idle and s3, so PV devices are not changed
and work after resume.

Signed-off-by: Jason Andryuk <jason.andryuk@amd.com>
Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Message-ID: <20251119224731.61497-2-jason.andryuk@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/xen/xenbus/xenbus_probe_frontend.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/drivers/xen/xenbus/xenbus_probe_frontend.c b/drivers/xen/xenbus/xenbus_probe_frontend.c
index 6d1819269cbe5..199917b6f77ca 100644
--- a/drivers/xen/xenbus/xenbus_probe_frontend.c
+++ b/drivers/xen/xenbus/xenbus_probe_frontend.c
@@ -148,11 +148,9 @@ static void xenbus_frontend_dev_shutdown(struct device *_dev)
}

static const struct dev_pm_ops xenbus_pm_ops = {
- .suspend = xenbus_dev_suspend,
- .resume = xenbus_frontend_dev_resume,
.freeze = xenbus_dev_suspend,
.thaw = xenbus_dev_cancel,
- .restore = xenbus_dev_resume,
+ .restore = xenbus_frontend_dev_resume,
};

static struct xen_bus_type xenbus_frontend = {
--
2.51.0