Re: [PATCH v3 0/8] Generalize start-powered-off property from ARM

[David Gibson]

On Mon, Aug 17, 2020 at 07:24:43AM +0200, Philippe Mathieu-Daudé wrote:
> On 8/17/20 6:47 AM, David Gibson wrote:
> > On Wed, Jul 22, 2020 at 11:56:49PM -0300, Thiago Jung Bauermann wrote:
> >> The ARM code has a start-powered-off property in ARMCPU, which is a
> >> subclass of CPUState. This property causes arm_cpu_reset() to set
> >> CPUState::halted to 1, signalling that the CPU should start in a halted
> >> state. Other architectures also have code which aim to achieve the same
> >> effect, but without using a property.
> >>
> >> The ppc/spapr version has a bug where QEMU does a KVM_RUN on the vcpu
> >> before cs->halted is set to 1, causing the vcpu to run while it's still in
> >> an unitialized state (more details in patch 3).
> >>
> >> Peter Maydell mentioned the ARM start-powered-off property and
> >> Eduardo Habkost suggested making it generic, so this patch series does
> >> that, for all cases which I was able to find via grep in the code.
> >>
> >> The only problem is that I was only able to test these changes on a ppc64le
> >> pseries KVM guest, so except for patches 2 and 3, all others are only
> >> build-tested. Also, my grasp of QOM lifecycle is basically non-existant so
> >> please be aware of that when reviewing this series.
> >>
> >> The last patch may be wrong, as pointed out by Eduardo, so I marked it as
> >> RFC. It may make sense to drop it.
> >>
> >> Applies cleanly on yesterday's master.
> > 
> > This series appears to break the Travis build for a MIPS target:
> > 
> > Unexpected error in qdev_prop_set_after_realize() at 
> > /home/travis/build/dgibson/qemu/hw/core/qdev-properties.c:30:
> > qemu-system-mips64el: Attempt to set property 'start-powered-off' on 
> > anonymous device (type 'I6400-mips64-cpu') after it was realized
> > Broken pipe
> > /home/travis/build/dgibson/qemu/tests/qtest/libqtest.c:175: kill_qemu() 
> > detected QEMU death from signal 6 (Aborted) (core dumped)
> > Aborted (core dumped)
> > ERROR qom-test - too few tests run (expected 8, got 0)
> > /home/travis/build/dgibson/qemu/tests/Makefile.include:650: recipe for 
> > target 'check-qtest-mips64el' failed
> 
> Good catch. hw/mips/cps.c, hw/ppc/e500.c and hw/sparc/sun4m.c are
> incorrectly setting the property after the cpu is realized because
> the cpu is created with cpu_create(). We need to create them with
> object_initialize_child() and realize them manually with qdev_realize().

Thiago, can you fix that up and repost please.


-- 
David Gibson                    | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au  | minimalist, thank you.  NOT _the_ _other_
                                | _way_ _around_!
http://www.ozlabs.org/~dgibson

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