On Fri, 7 Jun 2024 12:56:45 +0100 Salil Mehta <salil.me...@huawei.com> wrote:
> OSPM evaluates _EVT method to map the event. The CPU hotplug event eventually > results in start of the CPU scan. Scan figures out the CPU and the kind of > event(plug/unplug) and notifies it back to the guest. Update the GED AML _EVT > method with the call to \\_SB.CPUS.CSCN > > Also, macro CPU_SCAN_METHOD might be referred in other places like during GED > intialization so it makes sense to have its definition placed in some common > header file like cpu_hotplug.h. But doing this can cause compilation break > because of the conflicting macro definitions present in cpu.c and > cpu_hotplug.c one of the reasons is that you reusing legacy hw/acpi/cpu_hotplug.h, see below for suggestion. > and because both these files get compiled due to historic reasons of x86 world > i.e. decision to use legacy(GPE.2)/modern(GED) CPU hotplug interface happens > during runtime [1]. To mitigate above, for now, declare a new common macro > ACPI_CPU_SCAN_METHOD for CPU scan method instead. > (This needs a separate discussion later on for clean-up) > > Reference: > [1] > https://lore.kernel.org/qemu-devel/1463496205-251412-24-git-send-email-imamm...@redhat.com/ > > Co-developed-by: Keqian Zhu <zhukeqi...@huawei.com> > Signed-off-by: Keqian Zhu <zhukeqi...@huawei.com> > Signed-off-by: Salil Mehta <salil.me...@huawei.com> > Reviewed-by: Jonathan Cameron <jonathan.came...@huawei.com> > Reviewed-by: Gavin Shan <gs...@redhat.com> > Tested-by: Vishnu Pajjuri <vis...@os.amperecomputing.com> > Tested-by: Xianglai Li <lixiang...@loongson.cn> > Tested-by: Miguel Luis <miguel.l...@oracle.com> > Reviewed-by: Shaoqin Huang <shahu...@redhat.com> > Tested-by: Zhao Liu <zhao1....@intel.com> > --- > hw/acpi/cpu.c | 2 +- > hw/acpi/generic_event_device.c | 4 ++++ > include/hw/acpi/cpu_hotplug.h | 2 ++ > 3 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/hw/acpi/cpu.c b/hw/acpi/cpu.c > index 473b37ba88..af2b6655d2 100644 > --- a/hw/acpi/cpu.c > +++ b/hw/acpi/cpu.c > @@ -327,7 +327,7 @@ const VMStateDescription vmstate_cpu_hotplug = { > #define CPUHP_RES_DEVICE "PRES" > #define CPU_LOCK "CPLK" > #define CPU_STS_METHOD "CSTA" > -#define CPU_SCAN_METHOD "CSCN" > +#define CPU_SCAN_METHOD ACPI_CPU_SCAN_METHOD > #define CPU_NOTIFY_METHOD "CTFY" > #define CPU_EJECT_METHOD "CEJ0" > #define CPU_OST_METHOD "COST" > diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c > index 54d3b4bf9d..63226b0040 100644 > --- a/hw/acpi/generic_event_device.c > +++ b/hw/acpi/generic_event_device.c > @@ -109,6 +109,10 @@ void build_ged_aml(Aml *table, const char *name, > HotplugHandler *hotplug_dev, > aml_append(if_ctx, aml_call0(MEMORY_DEVICES_CONTAINER "." > MEMORY_SLOT_SCAN_METHOD)); > break; > + case ACPI_GED_CPU_HOTPLUG_EVT: > + aml_append(if_ctx, aml_call0(ACPI_CPU_CONTAINER "." > + ACPI_CPU_SCAN_METHOD)); I don't particularly like exposing cpu hotplug internals for outside code and then making that code do plumbing hoping that nothing will explode in the future. build_cpus_aml() takes event_handler_method to create a method that can be called by platform. What I suggest is to call that method here instead of trying to expose CPU hotplug internals and manually building call path here. aka: build_cpus_aml(event_handler_method = PATH_TO_GED_DEVICE.CSCN) and then call here aml_append(if_ctx, aml_call0(CSCN)); which will call CSCN in GED scope, that was be populated by build_cpus_aml() to do cpu scan properly without need to expose cpu hotplug internal names and then trying to fixup conflicts caused by that. PS: we should do the same for memory hotplug, we see in context above > + break; > case ACPI_GED_PWR_DOWN_EVT: > aml_append(if_ctx, > aml_notify(aml_name(ACPI_POWER_BUTTON_DEVICE), > diff --git a/include/hw/acpi/cpu_hotplug.h b/include/hw/acpi/cpu_hotplug.h > index 48b291e45e..ef631750b4 100644 > --- a/include/hw/acpi/cpu_hotplug.h > +++ b/include/hw/acpi/cpu_hotplug.h > @@ -20,6 +20,8 @@ > #include "hw/acpi/cpu.h" > > #define ACPI_CPU_HOTPLUG_REG_LEN 12 > +#define ACPI_CPU_SCAN_METHOD "CSCN" > +#define ACPI_CPU_CONTAINER "\\_SB.CPUS" > > typedef struct AcpiCpuHotplug { > Object *device;
