On Mon, Jun 04, 2018 at 12:33:04PM +0200, Max Reitz wrote: > On 2018-06-04 12:27, Daniel P. Berrangé wrote: > > The RUN_STATE_PRECONFIG state is not supposed to be reachable unless the > > --preconfig argument is given to QEMU, but when it was introduced in: > > > > commit 047f7038f586d2150f16c6d9ba9cfd0479f0f6ac > > Author: Igor Mammedov <imamm...@redhat.com> > > Date: Fri May 11 19:24:43 2018 +0200 > > > > cli: add --preconfig option > > > > The global 'current_run_state' variable was changed to have an initial > > value of RUN_STATE_PRECONFIG regardless of whether --preconfig is given. > > > > It then relies on the main loop to toggle it back to RUN_STATE_PRELAUNCH > > when --preconfig is not given. This is racy because it means that there > > is a window where QEMU is in RUN_STATE_PRECONFIG despite --preconfig not > > being given. This can be seen with the failure: > > > > $ echo | x86_64-softmmu/qemu-system-x86_64 -monitor stdio > > QEMU 2.12.50 monitor - type 'help' for more information > > (qemu) > > HMP not available in preconfig state, use QMP instead > > > > Signed-off-by: Daniel P. Berrangé <berra...@redhat.com> > > --- > > vl.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > This indeed fixes the issue that the preconfig state is reachable > without --preconfig, but it still keeps the main loop being invoked > twice (which means that e.g. HMP will process a single character before > the main loop is actually really invoked: > > $ echo quit | x86_64-softmmu/qemu-system-x86_64 \ > -drive file=/dev/null,if=ide,readonly=on -monitor stdio > QEMU 2.12.50 monitor - type 'help' for more information > (qemu) qqemu-system-x86_64: Initialization of device ide-hd failed: > Block node is read-only > > (Note the "q" before "qemu-system-x86_64")) > > (Naively,) I agree with Michal that the main loop should only be invoked > twice if --preconfig has been given, which is implemented by his patch: > > http://lists.nongnu.org/archive/html/qemu-devel/2018-06/msg00367.html
I think we probably need a combination of both patches for maximum safety. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
