On Thu, 14 Feb 2019 08:52:25 +0800
Wei Yang <richardw.y...@linux.intel.com> wrote:
> Currently we do device realization like below:
>
> hotplug_handler_pre_plug()
> dc->realize()
> hotplug_handler_plug()
>
> Before we do device realization and plug, we would allocate necessary
> resources and check the capacity.
'capacity' probably is not right word to use here
maybe s/the capacity/if 'memory-hotplug-support' property is enabled/
>
> While we leave acpi_memory_hotplug capacity check in the last step. This
wouldn't use 'leave' and 'capacity' here either, pls rephrase.
> looks not comply with current architecture and does some unnecessary
s/looks not/doesn't/
> work.
add more explanation about 'unnecessary work'.
problem as I see it, is that after successful pc_dimm_plug()
we get into piix4_device_plug_cb() and since
s->acpi_memory_hotplug.is_enabled == false
and all other 'if' conditions also false we would endup
at g_assert_not_reached() causing QEMU crash in piix4 case
and with error_abort up the call chain in case of ich9.
> This patch abstract the check on acpi_memory_hotplug capacity in
> pre_plug stage.
>
> Signed-off-by: Wei Yang <richardw.y...@linux.intel.com>
> ---
> hw/acpi/piix4.c | 14 ++++++++++++--
> hw/i386/pc.c | 8 ++++++++
doesn't look complete, why did you skip on similar code in ich9
(Q35 machine)?
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> index e330f24c71..c97b747496 100644
> --- a/hw/acpi/piix4.c
> +++ b/hw/acpi/piix4.c
> @@ -370,13 +370,22 @@ static void piix4_pm_powerdown_req(Notifier *n, void
> *opaque)
> acpi_pm1_evt_power_down(&s->ar);
> }
>
> +static void piix4_device_pre_plug_cb(HotplugHandler *hotplug_dev,
> + DeviceState *dev, Error **errp)
> +{
> + PIIX4PMState *s = PIIX4_PM(hotplug_dev);
> +
> + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) &&
> + !s->acpi_memory_hotplug.is_enabled)
> + error_setg(errp,
> + "memory hotplug is not enabled: PIIX4 memory hotplug disabled");
> +}
> static void piix4_device_plug_cb(HotplugHandler *hotplug_dev,
> DeviceState *dev, Error **errp)
> {
> PIIX4PMState *s = PIIX4_PM(hotplug_dev);
>
> - if (s->acpi_memory_hotplug.is_enabled &&
> - object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
> if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
> nvdimm_acpi_plug_cb(hotplug_dev, dev);
> } else {
> @@ -702,6 +711,7 @@ static void piix4_pm_class_init(ObjectClass *klass, void
> *data)
> */
> dc->user_creatable = false;
> dc->hotpluggable = false;
> + hc->pre_plug = piix4_device_pre_plug_cb;
> hc->plug = piix4_device_plug_cb;
> hc->unplug_request = piix4_device_unplug_request_cb;
> hc->unplug = piix4_device_unplug_cb;
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index 734d3268fa..3c6eed0cd3 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -1662,6 +1662,7 @@ static void pc_memory_pre_plug(HotplugHandler
> *hotplug_dev, DeviceState *dev,
> const PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
> const bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM);
> const uint64_t legacy_align = TARGET_PAGE_SIZE;
> + HotplugHandlerClass *hhc;
>
> /*
> * When -no-acpi is used with Q35 machine type, no ACPI is built,
> @@ -1674,6 +1675,13 @@ static void pc_memory_pre_plug(HotplugHandler
> *hotplug_dev, DeviceState *dev,
> return;
> }
>
> + /*
> + * Check acpi_dev memory hotplug capacity
> + */
> + hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
> + if (hcc->pre_plug)
> + hhc->pre_plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, errp);
use hotplug_handler_pre_plug() instead of open-coding check
> if (is_nvdimm && !pcms->acpi_nvdimm_state.is_enabled) {
> error_setg(errp, "nvdimm is not enabled: missing 'nvdimm' in '-M'");
> return;
