Re: [PATCH RFC V2 24/37] hw/acpi: Update ACPI GED framework to support vCPU Hotplug

[Michael S. Tsirkin]

On Tue, Sep 26, 2023 at 11:37:38AM +0000, Salil Mehta wrote:
> > From: Michael S. Tsirkin <mst@redhat.com>
> > Sent: Tuesday, September 26, 2023 12:02 PM
> > To: Salil Mehta <salil.mehta@huawei.com>
> > Cc: qemu-devel@nongnu.org; qemu-arm@nongnu.org; maz@kernel.org; jean-
> > philippe@linaro.org; Jonathan Cameron <jonathan.cameron@huawei.com>;
> > lpieralisi@kernel.org; peter.maydell@linaro.org;
> > richard.henderson@linaro.org; imammedo@redhat.com; andrew.jones@linux.dev;
> > david@redhat.com; philmd@linaro.org; eric.auger@redhat.com;
> > will@kernel.org; ardb@kernel.org; oliver.upton@linux.dev;
> > pbonzini@redhat.com; gshan@redhat.com; rafael@kernel.org;
> > borntraeger@linux.ibm.com; alex.bennee@linaro.org; linux@armlinux.org.uk;
> > darren@os.amperecomputing.com; ilkka@os.amperecomputing.com;
> > vishnu@os.amperecomputing.com; karl.heubaum@oracle.com;
> > miguel.luis@oracle.com; salil.mehta@opnsrc.net; zhukeqian
> > <zhukeqian1@huawei.com>; wangxiongfeng (C) <wangxiongfeng2@huawei.com>;
> > wangyanan (Y) <wangyanan55@huawei.com>; jiakernel2@gmail.com;
> > maobibo@loongson.cn; lixianglai@loongson.cn
> > Subject: Re: [PATCH RFC V2 24/37] hw/acpi: Update ACPI GED framework to
> > support vCPU Hotplug
> > 
> > On Tue, Sep 26, 2023 at 11:04:23AM +0100, Salil Mehta wrote:
> > > ACPI GED shall be used to convey to the guest kernel about any CPU hot-
> > (un)plug
> > > events. Therefore, existing ACPI GED framework inside QEMU needs to be
> > enhanced
> > > to support CPU hotplug state and events.
> > >
> > > Co-developed-by: Salil Mehta <salil.mehta@huawei.com>
> > 
> > Co-developed with yourself?
> > 
> > didn't you co-develop this with xianglai li?
> 
> No, our effort is quite old ARM patch-set existed since the year 2020
> without any change. Please check the original patch-set here:
> 
> https://lore.kernel.org/qemu-devel/20200613213629.21984-11-salil.mehta@huawei.com/
> 
> 
> To be fair to the authors, it will not be right to add another SOB here.
> 

I see. And what's the difference with patches that xianglai li posted?
Are they both rebases of the same old patch then?

> 
> > 
> > Just include his S.O.B then, and drop the non-standard Co-developed-by.
> 
> Co-developed-by Tag has been added to ensure main authors of the patch
> get highlighted clearly.

I think I don't know the patch provenance at this point.

> 
> > 
> > 
> > 
> > > Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> > > Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
> > > Signed-off-by: Keqian Zhu <zhukeqian1@huawei.com>
> > > Signed-off-by: Salil Mehta <salil.mehta@huawei.com>
> > 
> > 
> > 
> > > ---
> > >  hw/acpi/generic_event_device.c | 10 ++++++++++
> > >  1 file changed, 10 insertions(+)
> > >
> > > diff --git a/hw/acpi/generic_event_device.c
> > b/hw/acpi/generic_event_device.c
> > > index ad252e6a91..0266733a54 100644
> > > --- a/hw/acpi/generic_event_device.c
> > > +++ b/hw/acpi/generic_event_device.c
> > > @@ -12,6 +12,7 @@
> > >  #include "qemu/osdep.h"
> > >  #include "qapi/error.h"
> > >  #include "hw/acpi/acpi.h"
> > > +#include "hw/acpi/cpu.h"
> > >  #include "hw/acpi/generic_event_device.h"
> > >  #include "hw/irq.h"
> > >  #include "hw/mem/pc-dimm.h"
> > > @@ -239,6 +240,8 @@ static void acpi_ged_device_plug_cb(HotplugHandler
> > *hotplug_dev,
> > >          } else {
> > >              acpi_memory_plug_cb(hotplug_dev, &s->memhp_state, dev,
> > errp);
> > >          }
> > > +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> > > +        acpi_cpu_plug_cb(hotplug_dev, &s->cpuhp_state, dev, errp);
> > >      } else {
> > >          error_setg(errp, "virt: device plug request for unsupported
> > device"
> > >                     " type: %s", object_get_typename(OBJECT(dev)));
> > > @@ -253,6 +256,8 @@ static void acpi_ged_unplug_request_cb(HotplugHandler
> > *hotplug_dev,
> > >      if ((object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
> > >                         !(object_dynamic_cast(OBJECT(dev),
> > TYPE_NVDIMM)))) {
> > >          acpi_memory_unplug_request_cb(hotplug_dev, &s->memhp_state, dev,
> > errp);
> > > +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> > > +        acpi_cpu_unplug_request_cb(hotplug_dev, &s->cpuhp_state, dev,
> > errp);
> > >      } else {
> > >          error_setg(errp, "acpi: device unplug request for unsupported
> > device"
> > >                     " type: %s", object_get_typename(OBJECT(dev)));
> > > @@ -266,6 +271,8 @@ static void acpi_ged_unplug_cb(HotplugHandler
> > *hotplug_dev,
> > >
> > >      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> > >          acpi_memory_unplug_cb(&s->memhp_state, dev, errp);
> > > +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
> > > +        acpi_cpu_unplug_cb(&s->cpuhp_state, dev, errp);
> > >      } else {
> > >          error_setg(errp, "acpi: device unplug for unsupported device"
> > >                     " type: %s", object_get_typename(OBJECT(dev)));
> > > @@ -277,6 +284,7 @@ static void acpi_ged_ospm_status(AcpiDeviceIf *adev,
> > ACPIOSTInfoList ***list)
> > >      AcpiGedState *s = ACPI_GED(adev);
> > >
> > >      acpi_memory_ospm_status(&s->memhp_state, list);
> > > +    acpi_cpu_ospm_status(&s->cpuhp_state, list);
> > >  }
> > >
> > >  static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits
> > ev)
> > > @@ -291,6 +299,8 @@ static void acpi_ged_send_event(AcpiDeviceIf *adev,
> > AcpiEventStatusBits ev)
> > >          sel = ACPI_GED_PWR_DOWN_EVT;
> > >      } else if (ev & ACPI_NVDIMM_HOTPLUG_STATUS) {
> > >          sel = ACPI_GED_NVDIMM_HOTPLUG_EVT;
> > > +    } else if (ev & ACPI_CPU_HOTPLUG_STATUS) {
> > > +        sel = ACPI_GED_CPU_HOTPLUG_EVT;
> > >      } else {
> > >          /* Unknown event. Return without generating interrupt. */
> > >          warn_report("GED: Unsupported event %d. No irq injected", ev);
> > > --
> > > 2.34.1