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Re: [PATCH v7 0/8] Generalize start-powered-off property from ARM

From: Thiago Jung Bauermann
Subject: Re: [PATCH v7 0/8] Generalize start-powered-off property from ARM
Date: Mon, 31 Aug 2020 21:50:25 -0300
User-agent: mu4e 1.4.10; emacs 27.1

David Gibson <david@gibson.dropbear.id.au> writes:

> On Wed, Aug 26, 2020 at 02:55:27AM -0300, Thiago Jung Bauermann wrote:
>> This version fixes `make check` failures in ppc/e500.c, mips/cps.c and
>> sparc/sun4m.c. This was done by moving the qdev_realize_and_unref() call as
>> close as possible to the object_new() call, in order to keep the CPU object
>> construction as similar as possible to the earlier version which used
>> cpu_create().
>> I also had to change the patch which removed the main_cpu_reset() function
>> from sparc/sun4m.c. It was causing a `make check` failure but I can't
>> really explain why. See this message for a few more details:
>> https://lists.nongnu.org/archive/html/qemu-ppc/2020-08/msg00419.html
>> I dropped the Reviewed-by's on the changed patches because of these
>> changes.
>> Original cover letter below, followed by changelog:
>> 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.
> Applied to ppc-for-5.2, thanks.

Thank you!

Thiago Jung Bauermann
IBM Linux Technology Center

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