[PATCH v4] arm/virt: Add memory hot remove support

[PATCH v4] arm/virt: Add memory hot remove support

[Shameer Kolothum]

This adds support for memory(pc-dimm) hot remove on arm/virt that
uses acpi ged device.

NVDIMM hot removal is not yet supported.

Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
---
v2 --> v3
  -Addressed Eric's comments on v3. 
v2 --> v3
  -Addressed Eric's review comment and added check for NVDIMM.
RFC v1 --> v2
  -Rebased on top of latest Qemu master.
  -Dropped "RFC" and tested with kernel 5.7-rc6
---
 hw/acpi/generic_event_device.c | 29 ++++++++++++++++
 hw/arm/virt.c                  | 62 ++++++++++++++++++++++++++++++++--
 2 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
index 1cb34111e5..b8abdefa1c 100644
--- a/hw/acpi/generic_event_device.c
+++ b/hw/acpi/generic_event_device.c
@@ -193,6 +193,33 @@ 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) &&
+                       !(object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)))) {
+        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);
@@ -318,6 +345,8 @@ 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 caceb1e4a0..80ef2d7b7a 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -2177,11 +2177,68 @@ 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(&local_err,
+                   "memory hotplug is not enabled: missing acpi-ged device");
+        goto out;
+    }
+
+    if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
+        error_setg(&local_err,
+                   "nvdimm device hot unplug is not supported yet.");
+        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));
+    qdev_unrealize(dev);
+
+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,
@@ -2262,6 +2319,7 @@ 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->nvdimm_supported = true;
     mc->auto_enable_numa_with_memhp = true;
-- 
2.17.1

Re: [PATCH v4] arm/virt: Add memory hot remove support

[Auger Eric]

Hi Shameer,

On 6/22/20 2:41 PM, Shameer Kolothum wrote:
> This adds support for memory(pc-dimm) hot remove on arm/virt that
> uses acpi ged device.
> 
> NVDIMM hot removal is not yet supported.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Works fine for me when passing "movable_node" in the guest kernel
params. I am able to hotplug and hotremove PCDIMM slots several times

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Tested-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric
> ---
> v2 --> v3
>   -Addressed Eric's comments on v3. 
> v2 --> v3
>   -Addressed Eric's review comment and added check for NVDIMM.
> RFC v1 --> v2
>   -Rebased on top of latest Qemu master.
>   -Dropped "RFC" and tested with kernel 5.7-rc6
> ---
>  hw/acpi/generic_event_device.c | 29 ++++++++++++++++
>  hw/arm/virt.c                  | 62 ++++++++++++++++++++++++++++++++--
>  2 files changed, 89 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
> index 1cb34111e5..b8abdefa1c 100644
> --- a/hw/acpi/generic_event_device.c
> +++ b/hw/acpi/generic_event_device.c
> @@ -193,6 +193,33 @@ 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) &&
> +                       !(object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)))) {
> +        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);
> @@ -318,6 +345,8 @@ 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 caceb1e4a0..80ef2d7b7a 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2177,11 +2177,68 @@ 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(&local_err,
> +                   "memory hotplug is not enabled: missing acpi-ged device");
> +        goto out;
> +    }
> +
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
> +        error_setg(&local_err,
> +                   "nvdimm device hot unplug is not supported yet.");
> +        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));
> +    qdev_unrealize(dev);
> +
> +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,
> @@ -2262,6 +2319,7 @@ 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->nvdimm_supported = true;
>      mc->auto_enable_numa_with_memhp = true;
> 

Re: [PATCH v4] arm/virt: Add memory hot remove support

[Peter Maydell]

On Tue, 23 Jun 2020 at 11:15, Auger Eric <eric.auger@redhat.com> wrote:
>
> Hi Shameer,
>
> On 6/22/20 2:41 PM, Shameer Kolothum wrote:
> > This adds support for memory(pc-dimm) hot remove on arm/virt that
> > uses acpi ged device.
> >
> > NVDIMM hot removal is not yet supported.
> >
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Works fine for me when passing "movable_node" in the guest kernel
> params. I am able to hotplug and hotremove PCDIMM slots several times
>
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Tested-by: Eric Auger <eric.auger@redhat.com>

Thanks for the review, Eric.

Applied to target-arm.next, thanks.

-- PMM

Re: [PATCH v4] arm/virt: Add memory hot remove support

[Igor Mammedov]

On Mon, 22 Jun 2020 13:41:57 +0100
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:

> This adds support for memory(pc-dimm) hot remove on arm/virt that
> uses acpi ged device.
> 
> NVDIMM hot removal is not yet supported.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
> v2 --> v3
>   -Addressed Eric's comments on v3. 
> v2 --> v3
>   -Addressed Eric's review comment and added check for NVDIMM.
> RFC v1 --> v2
>   -Rebased on top of latest Qemu master.
>   -Dropped "RFC" and tested with kernel 5.7-rc6
> ---
>  hw/acpi/generic_event_device.c | 29 ++++++++++++++++
>  hw/arm/virt.c                  | 62 ++++++++++++++++++++++++++++++++--
>  2 files changed, 89 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/acpi/generic_event_device.c b/hw/acpi/generic_event_device.c
> index 1cb34111e5..b8abdefa1c 100644
> --- a/hw/acpi/generic_event_device.c
> +++ b/hw/acpi/generic_event_device.c
> @@ -193,6 +193,33 @@ 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) &&
> +                       !(object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)))) {
> +        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);
> @@ -318,6 +345,8 @@ 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 caceb1e4a0..80ef2d7b7a 100644
> --- a/hw/arm/virt.c
> +++ b/hw/arm/virt.c
> @@ -2177,11 +2177,68 @@ 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(&local_err,
> +                   "memory hotplug is not enabled: missing acpi-ged device");
> +        goto out;
> +    }
> +
> +    if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
> +        error_setg(&local_err,
> +                   "nvdimm device hot unplug is not supported yet.");
> +        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));
> +    qdev_unrealize(dev);

doesn't pc_dimm_unplug() do unrealize already?
(/me wonders why it doesn't explode here,
are we leaking a refference somewhere so dimm is still alive?)

> +
> +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,
> @@ -2262,6 +2319,7 @@ 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->nvdimm_supported = true;
>      mc->auto_enable_numa_with_memhp = true;

RE: [PATCH v4] arm/virt: Add memory hot remove support

[Shameerali Kolothum Thodi]

> -----Original Message-----
> From: Igor Mammedov [mailto:imammedo@redhat.com]
> Sent: 24 June 2020 15:09
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> Cc: qemu-devel@nongnu.org; qemu-arm@nongnu.org;
> peter.maydell@linaro.org; mst@redhat.com; Linuxarm
> <linuxarm@huawei.com>; xuwei (O) <xuwei5@huawei.com>;
> eric.auger@redhat.com; Zengtao (B) <prime.zeng@hisilicon.com>
> Subject: Re: [PATCH v4] arm/virt: Add memory hot remove support
> 
> On Mon, 22 Jun 2020 13:41:57 +0100
> Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:
> 
> > This adds support for memory(pc-dimm) hot remove on arm/virt that
> > uses acpi ged device.
> >
> > NVDIMM hot removal is not yet supported.
> >
> > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> > ---
> > v2 --> v3
> >   -Addressed Eric's comments on v3.
> > v2 --> v3
> >   -Addressed Eric's review comment and added check for NVDIMM.
> > RFC v1 --> v2
> >   -Rebased on top of latest Qemu master.
> >   -Dropped "RFC" and tested with kernel 5.7-rc6
> > ---
> >  hw/acpi/generic_event_device.c | 29 ++++++++++++++++
> >  hw/arm/virt.c                  | 62
> ++++++++++++++++++++++++++++++++--
> >  2 files changed, 89 insertions(+), 2 deletions(-)
> >
> > diff --git a/hw/acpi/generic_event_device.c
> b/hw/acpi/generic_event_device.c
> > index 1cb34111e5..b8abdefa1c 100644
> > --- a/hw/acpi/generic_event_device.c
> > +++ b/hw/acpi/generic_event_device.c
> > @@ -193,6 +193,33 @@ static void

[...]

> > +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));
> > +    qdev_unrealize(dev);
> 
> doesn't pc_dimm_unplug() do unrealize already?
> (/me wonders why it doesn't explode here,
> are we leaking a refference somewhere so dimm is still alive?)

Does it? From a quick look at the code it is not obvious.

pc_dimm_unplug()
  memory_device_unplug()
    memory_region_del_subregion()
  vmstate_unregister_ram()
    qemu_ram_unset_idstr()
    qemu_ram_unset_migratable()

If it does, then we may need to fix x86/ppc as well.

Thanks,
Shameer

> > +
> > +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,
> > @@ -2262,6 +2319,7 @@ 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->nvdimm_supported = true;
> >      mc->auto_enable_numa_with_memhp = true;

Re: [PATCH v4] arm/virt: Add memory hot remove support

[Peter Maydell]

On Wed, 24 Jun 2020 at 17:50, Shameerali Kolothum Thodi
<shameerali.kolothum.thodi@huawei.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Igor Mammedov [mailto:imammedo@redhat.com]
> > doesn't pc_dimm_unplug() do unrealize already?
> > (/me wonders why it doesn't explode here,
> > are we leaking a refference somewhere so dimm is still alive?)
>
> Does it? From a quick look at the code it is not obvious.
>
> pc_dimm_unplug()
>   memory_device_unplug()
>     memory_region_del_subregion()
>   vmstate_unregister_ram()
>     qemu_ram_unset_idstr()
>     qemu_ram_unset_migratable()
>
> If it does, then we may need to fix x86/ppc as well.

In any case this patch is now in master, so if you determine
that it needs a fix please send that as a followup patch.

thanks
-- PMM

Re: [PATCH v4] arm/virt: Add memory hot remove support

[Igor Mammedov]

On Wed, 24 Jun 2020 16:50:11 +0000
Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com> wrote:

> > -----Original Message-----
> > From: Igor Mammedov [mailto:imammedo@redhat.com]
> > Sent: 24 June 2020 15:09
> > To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@huawei.com>
> > Cc: qemu-devel@nongnu.org; qemu-arm@nongnu.org;
> > peter.maydell@linaro.org; mst@redhat.com; Linuxarm
> > <linuxarm@huawei.com>; xuwei (O) <xuwei5@huawei.com>;
> > eric.auger@redhat.com; Zengtao (B) <prime.zeng@hisilicon.com>
> > Subject: Re: [PATCH v4] arm/virt: Add memory hot remove support
> > 
> > On Mon, 22 Jun 2020 13:41:57 +0100
> > Shameer Kolothum <shameerali.kolothum.thodi@huawei.com> wrote:
> >   
> > > This adds support for memory(pc-dimm) hot remove on arm/virt that
> > > uses acpi ged device.
> > >
> > > NVDIMM hot removal is not yet supported.
> > >
> > > Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> > > ---
> > > v2 --> v3
> > >   -Addressed Eric's comments on v3.
> > > v2 --> v3
> > >   -Addressed Eric's review comment and added check for NVDIMM.
> > > RFC v1 --> v2
> > >   -Rebased on top of latest Qemu master.
> > >   -Dropped "RFC" and tested with kernel 5.7-rc6
> > > ---
> > >  hw/acpi/generic_event_device.c | 29 ++++++++++++++++
> > >  hw/arm/virt.c                  | 62  
> > ++++++++++++++++++++++++++++++++--  
> > >  2 files changed, 89 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/hw/acpi/generic_event_device.c  
> > b/hw/acpi/generic_event_device.c  
> > > index 1cb34111e5..b8abdefa1c 100644
> > > --- a/hw/acpi/generic_event_device.c
> > > +++ b/hw/acpi/generic_event_device.c
> > > @@ -193,6 +193,33 @@ static void  
> 
> [...]
> 
> > > +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));
> > > +    qdev_unrealize(dev);  
> > 
> > doesn't pc_dimm_unplug() do unrealize already?
> > (/me wonders why it doesn't explode here,
> > are we leaking a refference somewhere so dimm is still alive?)  
> 
> Does it? From a quick look at the code it is not obvious.
> 
> pc_dimm_unplug()
>   memory_device_unplug()
>     memory_region_del_subregion()
>   vmstate_unregister_ram()
>     qemu_ram_unset_idstr()
>     qemu_ram_unset_migratable()
> 
> If it does, then we may need to fix x86/ppc as well.
you are right, it's correct.
I mixed it up with:
 pc_memory_unplug()
     pc_dimm_unplug(PC_DIMM(dev), MACHINE(pcms));
     object_property_set_bool(OBJECT(dev), false, "realized", &error_abort);


> 
> Thanks,
> Shameer
> 
> > > +
> > > +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,  
> > > @@ -2262,6 +2319,7 @@ 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->nvdimm_supported = true;
> > >      mc->auto_enable_numa_with_memhp = true;  
>