Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NH. Peter Anvin <hpa@zytor.com>

This patch fixes compilation error on ia64.
include asm/xen/hypervisor.h instead of asm-x86/xen/hypervisor.h
use xen_pv_domain() instead of is_running_on_xen()

>   CC      drivers/xen/cpu_hotplug.o
> In file included from /linux-2.6/drivers/xen/cpu_hotplug.c:5:
> /linux-2.6/include/asm-x86/xen/hypervisor.h:44:22: error: asm/desc.h: No such file or directory
> /linux-2.6/include/asm-x86/xen/hypervisor.h:66:1: warning: "MULTI_UVMFLAGS_INDEX" redefined
> In file included from /linux-2.6/include/asm-x86/xen/hypervisor.h:52,
>                  from /linux-2.6/drivers/xen/cpu_hotplug.c:5:
> /linux-2.6/arch/ia64/include/asm/xen/hypercall.h:233:1: warning: this is the location of the previous definition
> /linux-2.6/drivers/xen/cpu_hotplug.c: In function 'setup_vcpu_hotplug_event':
> /linux-2.6/drivers/xen/cpu_hotplug.c:81: error: implicit declaration of function 'is_running_on_xen'
> make[4]: *** [drivers/xen/cpu_hotplug.o] Error 1
> make[4]: *** Waiting for unfinished jobs....
Signed-off-by: NIsaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NAlex Nixon <alex.nixon@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Note the changes from 2.6.18-xen CPU hotplugging:

A vcpu_down request from the remote admin via Xenbus both hotunplugs the
CPU, and disables it by removing it from the cpu_present map, and removing
its entry in /sys.

A vcpu_up request from the remote admin only re-enables the CPU, and does
not immediately bring the CPU up. A udev event is emitted, which can be
caught by the user if he wishes to automatically re-up CPUs when available,
or implement a more complex policy.
Signed-off-by: NAlex Nixon <alex.nixon@citrix.com>
Acked-by: NJeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>