vl: Add option to avoid stopping VM upon guest panic

The current default action of pausing a guest after a panic event
is received leaves the responsibility to resume guest execution to the
management layer. The reasons for this behavior are discussed here:
https://lore.kernel.org/qemu-devel/52148F88.5000509@redhat.com/

However, in instances like the case of older guests (Linux and
Windows) using a pvpanic device but missing support for the
PVPANIC_CRASHLOADED event, and Windows guests using the hv-crash
enlightenment, it is desirable to allow the guests to continue
running after sending a PVPANIC_PANICKED event. This allows such
guests to proceed to capture a crash dump and automatically reboot
without intervention of a management layer.

Add an option to avoid stopping a VM after a panic event is received,
by passing:

-action panic=none

in the command line arguments, or during runtime by using an upcoming
QMP command.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alejandro Jimenez <alejandro.j.jimenez@oracle.com>
Message-Id: <1607705564-26264-3-git-send-email-alejandro.j.jimenez@oracle.com>
[Do not fix panic action in the variable, instead modify -no-shutdown. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alejandro Jimenez 2020-12-11 17:31:52 -05:00 committed by Paolo Bonzini
parent 2a5ad60b54
commit c753e8e725
6 changed files with 43 additions and 5 deletions

View file

@ -3899,6 +3899,8 @@ DEF("action", HAS_ARG, QEMU_OPTION_action,
" action when guest reboots [default=none]\n"
"-action shutdown=poweroff|pause\n"
" action when guest shuts down [default=poweroff]\n"
"-action panic=poweroff|pause|none\n"
" action when guest panics [default=poweroff]\n"
"-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n"
" action when watchdog fires [default=reset]\n",
QEMU_ARCH_ALL)
@ -3911,6 +3913,7 @@ SRST
Examples:
``-action panic=none``
``-action reboot=shutdown,shutdown=pause``
``-watchdog i6300esb -action watchdog=pause``