diff options
| author | Jan Beulich <jbeulich@suse.com> | 2021-03-24 11:34:32 +0100 |
|---|---|---|
| committer | Ian Jackson <iwj@xenproject.org> | 2021-03-26 17:02:55 +0000 |
| commit | e680cc48b7184d3489873d6776f84ba1fc238ced (patch) | |
| tree | e8f8b2da555c60de7816af41a2b919b2da79ad25 /docs | |
| parent | 8bfceeed789e4394a9c45403a19f29909f2b2641 (diff) | |
x86/HPET: don't enable legacy replacement mode unconditionally
Commit e1de4c196a2e ("x86/timer: Fix boot on Intel systems using ITSSPRC
static PIT clock gating") was reported to cause boot failures on certain
AMD Ryzen systems. Until we can figure out what the actual issue there
is, skip this new part of HPET setup by default. Introduce a "hpet"
command line option to allow enabling this on hardware where it's really
needed for Xen to boot successfully (i.e. where the PIT doesn't drive
the timer interrupt).
Since it makes little sense to introduce just "hpet=legacy-replacement",
also allow for a boolean argument as well as "broadcast" to replace the
separate "hpetbroadcast" option.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Ian Jackson <iwj@xenproject.org>
Release-Acked-by: Ian Jackson <iwj@xenproject.org>
Diffstat (limited to 'docs')
| -rw-r--r-- | docs/misc/xen-command-line.pandoc | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc index a0601ff838..deef6d0b4c 100644 --- a/docs/misc/xen-command-line.pandoc +++ b/docs/misc/xen-command-line.pandoc @@ -1274,9 +1274,26 @@ supported. See docs/misc/arm/big.LITTLE.txt for more information. When the hmp-unsafe option is disabled (default), CPUs that are not identical to the boot CPU will be parked and not used by Xen. +### hpet (x86) +> `= List of [ <boolean> | broadcast | legacy-replacement ]` + +> Default : `true`, `no-broadcast`, 'no-legacy-replacement` + +Controls Xen's use of the system's High Precision Event Timer. The boolean +allows to turn off use altogether. + +`broadcast` forces Xen to keep using the broadcast for CPUs in deep C-states +even when an RTC interrupt got enabled. + +`legacy-replacement` is intended to be used on platforms where the timer +interrupt doesn't get raised by the legacy PIT. This then also affects +raising of the RTC interrupt. + ### hpetbroadcast (x86) > `= <boolean>` +Deprecated alternative of `hpet=broadcast`. + ### hvm_debug (x86) > `= <integer>` |