RE: [Question] Regarding PMU initialization within the QEMU for ARM VCPUs

[Salil Mehta]

> From: Igor Mammedov [mailto:imammedo@redhat.com]
> Sent: Monday, June 8, 2020 1:00 PM
> 
> On Fri, 5 Jun 2020 16:38:37 +0000
> Salil Mehta <salil.mehta@huawei.com> wrote:
> 
> > > From: Igor Mammedov [mailto:imammedo@redhat.com]
> > > Sent: Friday, June 5, 2020 4:31 PM
> > > To: Andrew Jones <drjones@redhat.com>
> > > Cc: Salil Mehta <salil.mehta@huawei.com>; qemu-devel@nongnu.org;
> > > qemu-arm@nongnu.org; Peter Maydell <peter.maydell@linaro.org>; 
> > > mst@redhat.com
> > > Subject: Re: [Question] Regarding PMU initialization within the QEMU for 
> > > ARM
> > > VCPUs
> > >
> > > On Wed, 3 Jun 2020 11:37:45 +0200
> > > Andrew Jones <drjones@redhat.com> wrote:
> > >
> > > > On Mon, Jun 01, 2020 at 03:04:33PM +0000, Salil Mehta wrote:
> > > > > Hello,
> > > > > I could see below within function fdt_add_pmu_nodes() part of
> > > > > hw/arm/virt.c during virt machine initialization time:
> > > ...
> > > >
> > > > > Q4. This function  fdt_* looks to be wrongly named. The info
> > > > >     being initialized here shall be used even when ACPI is
> > > > >     being used. Initialization part and FDT info looked
> > > > >     mixed up here if I am right?
> > > >
> > > > Agreed. The function has the wrong name. mach-virt has many functions 
> > > > that
> > > > mix the initialization and fdt building together, but those functions 
> > > > are
> > > > named something like create_foo(). Patches welcome.
> > > that was where I gave up on cpu hotplug arm/virt the last time.
> >
> > Were you releasing the ARM objects as well? Or are you referring to some
> > other problem?
> I was talking about mix of FDT and device creation code.

Ok. I have worked around that for now. Maybe you would like to review
it in the cpuhp patches which I should be able to float this week to the
community.

Thanks
Salil.

> > > Ideally we should split out from create_foo() all firmware generation code
> > > (fdt) and move it to virt_machine_done time + make sure that it could be
> > > regenerated at reset time so guest would get updated FDT on reset.
> >
> > Agreed, just like ACPI part. That would be more cleaner.
> >
> > Thanks
> > Salil.