Hi Shameer, On 3/18/20 1:37 PM, Shameer Kolothum wrote: > This adds support for memory hot remove on arm/virt that > uses acpi ged device.
I gave this a try and it works fine if the PCDIMM slot was initially hotplugged: (QEMU) object-add qom-type=memory-backend-ram id=mem1 props.size=4294967296 {"return": {}} (QEMU) device_add driver=pc-dimm id=pcdimm1 memdev=mem1 (QEMU) device_del id=pcdimm1 {"return": {}} on guest I can see: [ 82.466321] Offlined Pages 262144 [ 82.541712] Offlined Pages 262144 [ 82.589236] Offlined Pages 262144 [ 82.969166] Offlined Pages 262144 However I noticed that if qemu is launched directly with -m 16G,maxmem=32G,slots=2 \ -object memory-backend-ram,id=mem1,size=4G \ -device pc-dimm,memdev=mem1,id=dimm1,driver=pc-dimm -device and then in the qmp shell: (QEMU) device_del id=dimm1 the hot-unplug fails in guest: [ 78.897407] Offlined Pages 262144 [ 79.260811] Offlined Pages 262144 [ 79.308105] Offlined Pages 262144 [ 79.333675] page:fffffe00137d1f40 refcount:1 mapcount:0 mapping:ffff0004ea9f20b1 index:0xaaab11c6e [ 79.335927] anon flags: 0x17ffff8000080024(uptodate|active|swapbacked) [ 79.337571] raw: 17ffff8000080024 dead000000000100 dead000000000122 ffff0004ea9f20b1 [ 79.339502] raw: 0000000aaab11c6e 0000000000000000 00000001ffffffff ffff0004fd4e3000 [ 79.341701] page dumped because: unmovable page [ 79.342887] page->mem_cgroup:ffff0004fd4e3000 [ 79.354729] page:fffffe00137d1f40 refcount:1 mapcount:0 mapping:ffff0004ea9f20b1 index:0xaaab11c6e [ 79.357012] anon flags: 0x17ffff8000080024(uptodate|active|swapbacked) [ 79.358658] raw: 17ffff8000080024 dead000000000100 dead000000000122 ffff0004ea9f20b1 [ 79.360611] raw: 0000000aaab11c6e 0000000000000000 00000001ffffffff ffff0004fd4e3000 [ 79.362560] page dumped because: unmovable page [ 79.363742] page->mem_cgroup:ffff0004fd4e3000 [ 79.368636] memory memory20: Offline failed. I did not expect this. The PCDIMM slot in that case does not seem to be interpreted as a hot-unpluggable one (?). I added Anshuman in cc. Thanks Eric > > Signed-off-by: Shameer Kolothum <shameerali.kolothum.th...@huawei.com> > --- > -RFC because linux kernel support for mem hot remove is just queued > for 5.7[1]. > -Tested with guest kernel 5.6-rc5 + [1] > > 1. https://patchwork.kernel.org/cover/11419301/ > --- > hw/acpi/generic_event_device.c | 28 +++++++++++++++++ > hw/arm/virt.c | 56 ++++++++++++++++++++++++++++++++-- > 2 files changed, 82 insertions(+), 2 deletions(-) > > diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c > index 021ed2bf23..3e28c110fa 100644 > --- a/hw/acpi/generic_event_device.c > +++ b/hw/acpi/generic_event_device.c > @@ -182,6 +182,32 @@ static void acpi_ged_device_plug_cb(HotplugHandler > *hotplug_dev, > } > } > > +static void acpi_ged_unplug_request_cb(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + AcpiGedState *s = ACPI_GED(hotplug_dev); > + > + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) { > + acpi_memory_unplug_request_cb(hotplug_dev, &s->memhp_state, dev, > errp); > + } else { > + error_setg(errp, "acpi: device unplug request for unsupported device" > + " type: %s", object_get_typename(OBJECT(dev))); > + } > +} > + > +static void acpi_ged_unplug_cb(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + AcpiGedState *s = ACPI_GED(hotplug_dev); > + > + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) { > + acpi_memory_unplug_cb(&s->memhp_state, dev, errp); > + } else { > + error_setg(errp, "acpi: device unplug for unsupported device" > + " type: %s", object_get_typename(OBJECT(dev))); > + } > +} > + > static void acpi_ged_send_event(AcpiDeviceIf *adev, AcpiEventStatusBits ev) > { > AcpiGedState *s = ACPI_GED(adev); > @@ -286,6 +312,8 @@ static void acpi_ged_class_init(ObjectClass *class, void > *data) > dc->vmsd = &vmstate_acpi_ged; > > hc->plug = acpi_ged_device_plug_cb; > + hc->unplug_request = acpi_ged_unplug_request_cb; > + hc->unplug = acpi_ged_unplug_cb; > > adevc->send_event = acpi_ged_send_event; > } > diff --git a/hw/arm/virt.c b/hw/arm/virt.c > index 94f93dda54..91974e4e80 100644 > --- a/hw/arm/virt.c > +++ b/hw/arm/virt.c > @@ -2096,11 +2096,62 @@ static void > virt_machine_device_plug_cb(HotplugHandler *hotplug_dev, > } > } > > +static void virt_dimm_unplug_request(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + VirtMachineState *vms = VIRT_MACHINE(hotplug_dev); > + Error *local_err = NULL; > + > + if (!vms->acpi_dev) { > + error_setg(errp, > + "memory hotplug is not enabled: missing acpi-ged device"); > + goto out; > + } > + > + hotplug_handler_unplug_request(HOTPLUG_HANDLER(vms->acpi_dev), dev, > + &local_err); > +out: > + error_propagate(errp, local_err); > +} > + > +static void virt_dimm_unplug(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + VirtMachineState *vms = VIRT_MACHINE(hotplug_dev); > + Error *local_err = NULL; > + > + hotplug_handler_unplug(HOTPLUG_HANDLER(vms->acpi_dev), dev, &local_err); > + if (local_err) { > + goto out; > + } > + > + pc_dimm_unplug(PC_DIMM(dev), MACHINE(vms)); > + object_property_set_bool(OBJECT(dev), false, "realized", NULL); > + > + out: > + error_propagate(errp, local_err); > +} > + > static void virt_machine_device_unplug_request_cb(HotplugHandler > *hotplug_dev, > DeviceState *dev, Error **errp) > { > - error_setg(errp, "device unplug request for unsupported device" > - " type: %s", object_get_typename(OBJECT(dev))); > + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) { > + virt_dimm_unplug_request(hotplug_dev, dev, errp); > + } else { > + error_setg(errp, "device unplug request for unsupported device" > + " type: %s", object_get_typename(OBJECT(dev))); > + } > +} > + > +static void virt_machine_device_unplug_cb(HotplugHandler *hotplug_dev, > + DeviceState *dev, Error **errp) > +{ > + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) { > + virt_dimm_unplug(hotplug_dev, dev, errp); > + } else { > + error_setg(errp, "virt: device unplug for unsupported device" > + " type: %s", object_get_typename(OBJECT(dev))); > + } > } > > static HotplugHandler *virt_machine_get_hotplug_handler(MachineState > *machine, > @@ -2181,6 +2232,7 @@ static void virt_machine_class_init(ObjectClass *oc, > void *data) > hc->pre_plug = virt_machine_device_pre_plug_cb; > hc->plug = virt_machine_device_plug_cb; > hc->unplug_request = virt_machine_device_unplug_request_cb; > + hc->unplug = virt_machine_device_unplug_cb; > mc->numa_mem_supported = true; > mc->auto_enable_numa_with_memhp = true; > mc->default_ram_id = "mach-virt.ram"; >