[Qemu-devel] [PATCH 1/1] spapr: Prevent boot CPU core removal

[Qemu-devel] [PATCH 1/1] spapr: Prevent boot CPU core removal

[Bharata B Rao]

Boot CPU is assumed to be always present in QEMU code. So
until that assumptions are gone, deny removal request.
In another words, QEMU won't support boot CPU core hot-unplug.

Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>
---
 hw/ppc/spapr_cpu_core.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
index 5a132bf..0dadf48 100644
--- a/hw/ppc/spapr_cpu_core.c
+++ b/hw/ppc/spapr_cpu_core.c
@@ -133,6 +133,11 @@ void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
     sPAPRDRConnectorClass *drck;
     Error *local_err = NULL;
 
+    if (index == 0) {
+        error_setg(errp, "Boot CPU core is unpluggable");
+        return;
+    }
+
     g_assert(drc);
 
     drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);
-- 
2.7.4

Re: [Qemu-devel] [PATCH 1/1] spapr: Prevent boot CPU core removal

[David Gibson]

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On Wed, Jul 27, 2016 at 10:44:42AM +0530, Bharata B Rao wrote:
> Boot CPU is assumed to be always present in QEMU code. So
> until that assumptions are gone, deny removal request.
> In another words, QEMU won't support boot CPU core hot-unplug.
> 
> Signed-off-by: Bharata B Rao <bharata@linux.vnet.ibm.com>

Applied to ppc-for-2.7, but I've changed the message slightly to avoid
the ambiguity between:
	un-pluggable - "may not be plugged (or unplugged)"
	unplug-able  - "may be unplugged"

> ---
>  hw/ppc/spapr_cpu_core.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/hw/ppc/spapr_cpu_core.c b/hw/ppc/spapr_cpu_core.c
> index 5a132bf..0dadf48 100644
> --- a/hw/ppc/spapr_cpu_core.c
> +++ b/hw/ppc/spapr_cpu_core.c
> @@ -133,6 +133,11 @@ void spapr_core_unplug(HotplugHandler *hotplug_dev, DeviceState *dev,
>      sPAPRDRConnectorClass *drck;
>      Error *local_err = NULL;
>  
> +    if (index == 0) {
> +        error_setg(errp, "Boot CPU core is unpluggable");
> +        return;
> +    }
> +
>      g_assert(drc);
>  
>      drck = SPAPR_DR_CONNECTOR_GET_CLASS(drc);

-- 
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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