Pull more xen updates from Juergen Gross:
- A small series for Xen event channels adding some sysfs nodes for per
pv-device settings and statistics, and two fixes of theoretical
problems.
- two minor fixes (one for an unlikely error path, one for a comment).
* tag 'for-linus-5.12b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen-front-pgdir-shbuf: don't record wrong grant handle upon error
xen: Replace lkml.org links with lore
xen/evtchn: use READ/WRITE_ONCE() for accessing ring indices
xen/evtchn: use smp barriers for user event ring
xen/events: add per-xenbus device event statistics and settings