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Re: [Qemu-devel] [FIX PATCH] spapr: Gracefully fail CPU thread unplug
From: |
David Gibson |
Subject: |
Re: [Qemu-devel] [FIX PATCH] spapr: Gracefully fail CPU thread unplug |
Date: |
Thu, 18 Aug 2016 10:57:04 +1000 |
User-agent: |
Mutt/1.6.2 (2016-07-01) |
On Wed, Aug 17, 2016 at 07:31:38PM +0530, Bharata B Rao wrote:
> sPAPR supports only Core level CPU plug and unplug, but nothing
> prevents user from issuing a device_del on the underlying thread
> device by using its qom path directly. This hits g_assert(hotplug_ctrl)
> in qdev_unplug().
>
> Gracefully reject such unplug requests from ->unplug() handler
>
> Reported-by: Shivaprasad G Bhat <address@hidden>
> Signed-off-by: Bharata B Rao <address@hidden>
Why isn't there a graceful failure if we return NULL from the
hotplug_handler()? Doesn't that indicate a bug in the generic code?
Couldn't the same error be triggered by attempting to unplug some
other random device - say the RTC on x86, or the NVRAM on POWER?
Also I only just noticed that we've had a misspelling here for ages:
"hotpug_handler".
> ---
> hw/ppc/spapr.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 30d6800..0e89d7d 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2344,6 +2344,9 @@ static void spapr_machine_device_unplug(HotplugHandler
> *hotplug_dev,
> return;
> }
> spapr_core_unplug(hotplug_dev, dev, errp);
> + } else {
> + error_setg(errp, "Unplug not supported for device type: %s",
> + object_get_typename(OBJECT(dev)));
> }
> }
>
> @@ -2359,6 +2362,7 @@ static HotplugHandler
> *spapr_get_hotpug_handler(MachineState *machine,
> DeviceState *dev)
> {
> if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) ||
> + object_dynamic_cast(OBJECT(dev), TYPE_CPU) ||
> object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
> return HOTPLUG_HANDLER(machine);
> }
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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