Under certain circumstances[0] Kata will attempt to use SHPC hotplug
for PCI devices on the guest. In fact we explicitly enable SHPC on
our PCI to PCI bridges, regardless of the qemu default.
SHPC was designed a long, long time ago for physical hotplugging and
works very poorly for a virtual environment. In particular it has a
mandatory 5s delay to allow a (real, human) operator to back out the
operation if they press a button by mistake. This alone makes it
unusable for a fast start up application like Kata.
Worse, the agent forces a PCI rescan during startup. That will race
with the SHPC hotplug operation causing the device to go into a bad
state where config space can't be accessed from the guest at all.
The only reason we've sort of gotten away with this is that our
default guest kernel configuration triggers what's arguably a kernel
bug effectively disabling SHPC. That makes the agent rescan the only
reason we see the new device.
Now that we require a qemu >=6.1, which includes ACPI PCI hotplug on
the q35 machine, we can explicitly disable SHPC in all cases. It's
nothing but trouble.
fixes#2174
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Removed all TOCs now that GitHub auto-generates them.
Also updated the documentation requirements doc removing the requirement
to add a TOC.
Fixes: #2022.
Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
Keeping around two different x86 machines has no added value
and require more tests and maintenance. Prefer the q35 machine
since it has more features and drop the pc machine.
Fixes#1953
Depends-on: github.com/kata-containers/tests#3586
Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
