On Mon, Oct 31, 2022 at 01:19:30PM +0000, Daniel P. Berrangé wrote: > The TCO watchdog is unconditionally integrated into the Q35 machine > type by default, but at the same time is unconditionally disabled > from firing by a host config option that overrides guest OS attempts > to enable it. People have to know to set a magic -global to make > it non-broken > > IOW we're exposing a broken watchdog by default to all Q35 machines, > but which to the guest OS & its apps looks fully functional :-( > > This behaviour was set in response to feedback from Michael: > > https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg07128.html > > "I think sample high is a safer default." > > but as explained in the commit message in the last patch, I think the > watchdog defaults were already safe without that pin strap setting. > The guest OS needs to take explicit action to clear the guest visible > 'no reboot' flag, and so we don't need a second guest hidden 'no reboot' > flag to override that choice IMHO. Am I missing something ? > > NB, I'm toggling this for 7.2 machine type since that's the current > git latest machine. Since this has already been "broken" for 7 years > though, I am ambivalent about whether we try todo this for 7.2, vs > just wait until the 8.0 machine types arrive.
So I expect v2 with minor issues fixed and hopefully a fixed property (we can debate removing it down the road if we want). > Daniel P. Berrangé (4): > hw/acpi: add trace events for TCO watchdog register access > hw/isa: add trace events for ICH9 LPC chip config access > hw/watchdog: add trace events for watchdog action handling > hw/isa: enable TCO watchdog reboot pin strap by default > > hw/acpi/tco.c | 41 +++++++++++++++++++++++++++------------- > hw/acpi/trace-events | 2 ++ > hw/i386/pc.c | 4 +++- > hw/isa/lpc_ich9.c | 5 ++++- > hw/isa/trace-events | 4 ++++ > hw/watchdog/trace-events | 4 ++++ > hw/watchdog/watchdog.c | 4 ++++ > tests/qtest/tco-test.c | 2 +- > 8 files changed, 50 insertions(+), 16 deletions(-) > > -- > 2.37.3