On Tue, 31 Dec 2013, Konrad Rzeszutek Wilk wrote:
> From: Mukesh Rathor <mukesh.rat...@oracle.com>
>
> As we do not have yet a mechanism for that.
>
> This also impacts the ARM/ARM64 code (which does not have
> hotplug support yet).
>
> Signed-off-by: Mukesh Rathor <mukesh.rat...@oracle.com>
> Signed-off-by: Konrad Rzeszutek Wilk <konrad.w...@oracle.com>
> ---
> drivers/xen/cpu_hotplug.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/xen/cpu_hotplug.c b/drivers/xen/cpu_hotplug.c
> index cc6513a..5f80802 100644
> --- a/drivers/xen/cpu_hotplug.c
> +++ b/drivers/xen/cpu_hotplug.c
> @@ -4,6 +4,7 @@
>
> #include <xen/xen.h>
> #include <xen/xenbus.h>
> +#include <xen/features.h>
>
> #include <asm/xen/hypervisor.h>
> #include <asm/cpu.h>
> @@ -102,7 +103,8 @@ static int __init setup_vcpu_hotplug_event(void)
> static struct notifier_block xsn_cpu = {
> .notifier_call = setup_cpu_watcher };
>
> - if (!xen_pv_domain())
> + /* PVH/ARM/ARM64 TBD/FIXME: future work */
> + if (!xen_pv_domain() || xen_feature(XENFEAT_auto_translated_physmap))
> return -ENODEV;
>
> register_xenstore_notifier(&xsn_cpu);
Sorry for being a bit obnoxious but I was thinking that using a
xen_feature(XENFEAT_auto_translated_physmap) check is conceptually
wrong, because cpu hotplug and nested paging are orthogonal.
Given that we most probably want to follow the PV path for cpu_hotplug
(that is using drivers/xen/cpu_hotplug.c), is there actually a problem
with building and initializing it on PVH guests?
If it works as it is, I would be tempted to leave it for now.
Otherwise the patch is OK and you can add my Acked-by.
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