Re: [Xen-devel] [PATCH v5 0/6] xen/PMU: PMU support for Xen PV(H) guests

[Julien Grall <julien.grall@citrix.com>]

Hi,

On 07/08/15 16:35, David Vrabel wrote:
> On 02/07/15 15:53, Boris Ostrovsky wrote:
>> I haven't posted Linux part of PV(H) VPMU support in a while but now
>> that (hopefully) the hypervisor part is getting close to be done I
>> think it's time to post it again.
>>
>> There are very few differences compared to the last version, mostly due
>> to updates in shared structures layouts. Patches 1 and 4 have no changes
>> at all and patch 5 has minor changes due to rebasing so I kept David's
>> Reviewed-by tag.
> 
> This breaks the arm and arm64 builds.
> 
> In file included from
> /local/davidvr/work/k.org/tip/drivers/xen/sys-hypervisor.c:23:0:
> /local/davidvr/work/k.org/tip/include/xen/interface/xenpmu.h:91:22:
> error: field ‘pmu’ has incomplete type
>   struct xen_pmu_arch pmu;
>                       ^
> /local/davidvr/work/k.org/tip/drivers/xen/sys-hypervisor.c: In function
> ‘pmu_mode_store’:
> /local/davidvr/work/k.org/tip/drivers/xen/sys-hypervisor.c:403:2: error:
> implicit declaration of function ‘HYPERVISOR_xenpmu_op’
> [-Werror=implicit-function-declaration]
>   ret = HYPERVISOR_xenpmu_op(XENPMU_mode_set, &xp);
>   ^

There is no PMU support for the moment on ARM and this hypercall is only
used for x86. I would introduce a new CONFIG (CONFIG_XEN_PMMU) which is
enabled for x86 and disabled for ARM.

> cc1: some warnings being treated as errors
> /local/davidvr/work/k.org/tip/scripts/Makefile.build:258: recipe for
> target 'drivers/xen/sys-hypervisor.o' failed
> make[3]: *** [drivers/xen/sys-hypervisor.o] Error 1
> make[3]: *** Waiting for unfinished jobs....
> /local/davidvr/work/k.org/tip/drivers/xen/xenfs/xensyms.c: In function
> ‘xensyms_next_sym’:
> /local/davidvr/work/k.org/tip/drivers/xen/xenfs/xensyms.c:34:2: error:
> implicit declaration of function ‘HYPERVISOR_dom0_op’
> [-Werror=implicit-function-declaration]
>   ret = HYPERVISOR_dom0_op(&xs->op);
>   ^

DOM0 op doesn't exists for ARM and xensyms is not even plumbed. I would
make sure that XEN_SYMS is not enabled for ARM maybe adding the line
below in the kconfig?

depends on X86 && XEN_DOM0 && XENFS

Regards,

-- 
Julien Grall