From: "Daniel P. Berrangé" <berrange@redhat.com>
To: qemu-devel@nongnu.org
Cc: "Laurent Vivier" <lvivier@redhat.com>,
"Richard Henderson" <richard.henderson@linaro.org>,
"Ani Sinha" <ani@anisinha.ca>,
"Igor Mammedov" <imammedo@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Thomas Huth" <thuth@redhat.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Eduardo Habkost" <eduardo@habkost.net>,
"Marcel Apfelbaum" <marcel.apfelbaum@gmail.com>,
"Richard W.M. Jones" <rjones@redhat.com>,
"Daniel P. Berrangé" <berrange@redhat.com>
Subject: [PATCH 0/4] hw: make TCO watchdog actually work by default for Q35
Date: Mon, 31 Oct 2022 13:19:30 +0000 [thread overview]
Message-ID: <20221031131934.425448-1-berrange@redhat.com> (raw)
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.
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
next reply other threads:[~2022-10-31 13:24 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-31 13:19 Daniel P. Berrangé [this message]
2022-10-31 13:19 ` [PATCH 1/4] hw/acpi: add trace events for TCO watchdog register access Daniel P. Berrangé
2022-10-31 13:34 ` Richard W.M. Jones
2022-10-31 13:19 ` [PATCH 2/4] hw/isa: add trace events for ICH9 LPC chip config access Daniel P. Berrangé
2022-10-31 13:36 ` Richard W.M. Jones
2022-10-31 13:19 ` [PATCH 3/4] hw/watchdog: add trace events for watchdog action handling Daniel P. Berrangé
2022-10-31 13:36 ` Richard W.M. Jones
2022-10-31 15:46 ` Philippe Mathieu-Daudé
2022-10-31 13:19 ` [PATCH 4/4] hw/isa: enable TCO watchdog reboot pin strap by default Daniel P. Berrangé
2022-10-31 13:40 ` Richard W.M. Jones
2022-10-31 13:50 ` [PATCH 0/4] hw: make TCO watchdog actually work by default for Q35 Daniel P. Berrangé
2022-10-31 15:48 ` Michael S. Tsirkin
2022-11-01 12:57 ` Igor Mammedov
2022-11-01 13:03 ` Daniel P. Berrangé
2022-11-10 16:29 ` Michael S. Tsirkin
2022-11-10 18:21 ` Daniel P. Berrangé
2022-11-10 16:30 ` Michael S. Tsirkin
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