RE: [PATCH V15 0/7] Add architecture agnostic code to support vCPU Hotplug

[Salil Mehta]

>  From: qemu-arm-bounces+salil.mehta=huawei.com@nongnu.org <qemu-
>  arm-bounces+salil.mehta=huawei.com@nongnu.org> On Behalf Of Salil
>  Mehta via
>  Sent: Monday, July 15, 2024 3:14 PM
>  To: Igor Mammedov <imammedo@redhat.com>
>  
>  Hi Igor,
>  
>  >  From: Igor Mammedov <imammedo@redhat.com>
>  >  Sent: Monday, July 15, 2024 2:55 PM
>  >  To: Salil Mehta <salil.mehta@huawei.com>
>  >
>  >  On Sat, 13 Jul 2024 19:25:09 +0100
>  >  Salil Mehta <salil.mehta@huawei.com> wrote:
>  >
>  >  > [Note: References are present at the last after the revision
>  > history]  >  > Virtual CPU hotplug support is being added across
>  > various architectures  [1][3].
>  >  > This series adds various code bits common across all architectures:
>  >  >
>  >  > 1. vCPU creation and Parking code refactor [Patch 1] 2. Update ACPI
>  > > GED framework to support vCPU Hotplug [Patch 2,3] 3. ACPI CPUs AML
>  > > code change [Patch 4,5] 4. Helper functions to support unrealization
>  > > of CPU objects [Patch 6,7]
>  >
>  >  with patch 1 and 3 fixed should be good to go.
>  >
>  >  Salil,
>  >  Can you remind me what happened to migration part of this?
>  >  Ideally it should be a part of of this series as it should be common
>  > for  everything that uses GED and should be a conditional part of
>  > GED's  VMSTATE.
>  >
>  >  If this series is just a common base and no actual hotplug on top of
>  > it is  merged in this release (provided patch 13 is fixed), I'm fine
>  > with migration  bits being a separate series on top.
>  >
>  >  However if some machine would be introducing cpu hotplug in the same
>  > release, then the migration part should be merged before it or be a
>  > part  that cpu hotplug series.
>  
>  We have tested Live/Pseudo Migration and it seem to work with the
>  changes part of the architecture specific patch-set.
>  
>  Ampere: https://lore.kernel.org/all/e17e28ac-28c7-496f-b212-
>  2c9b552dbf63@amperemail.onmicrosoft.com/
>  Oracle: https://lore.kernel.org/all/46D74D30-EE54-4AD2-8F0E-
>  BA5627FAA63E@oracle.com/
>  
>  
>  For ARM, please check below patch part of RFC V3 for changes related to
>  migration:
>  https://lore.kernel.org/qemu-devel/20240613233639.202896-15-
>  salil.mehta@huawei.com/


Do you wish to move below change into this path-set and make it common
to all instead?


diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index 63226b0040..e92ce07955 100644
--- a/hw/acpi/generic_event_device.c
+++ b/hw/acpi/generic_event_device.c
@@ -333,6 +333,16 @@ static const VMStateDescription vmstate_memhp_state = {
     }
 };
 
+static const VMStateDescription vmstate_cpuhp_state = {
+    .name = "acpi-ged/cpuhp",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_CPU_HOTPLUG(cpuhp_state, AcpiGedState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
 static const VMStateDescription vmstate_ged_state = {
     .name = "acpi-ged-state",
     .version_id = 1,
@@ -381,6 +391,7 @@ static const VMStateDescription vmstate_acpi_ged = {
     },
     .subsections = (const VMStateDescription * const []) {
         &vmstate_memhp_state,
+        &vmstate_cpuhp_state,
         &vmstate_ghes_state,
         NULL
     }

Maybe I can add a separate patch for this in the end? Please confirm.

Thanks
Salil.