Re: [Xen-devel] [PATCH V3] tools/libxc, xen/x86: Added xc_set_mem_access_multi()

[Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>]

On 09/06/2016 05:28 PM, Jan Beulich wrote:
>>>> On 06.09.16 at 16:21, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
>> On 09/06/2016 05:07 PM, Jan Beulich wrote:
>>>>>> On 06.09.16 at 12:00, <rcojocaru@xxxxxxxxxxxxxxx> wrote:
>>>> --- a/xen/arch/arm/p2m.c
>>>> +++ b/xen/arch/arm/p2m.c
>>>> @@ -1836,6 +1836,15 @@ long p2m_set_mem_access(struct domain *d, gfn_t 
>>>> gfn, uint32_t nr,
>>>>      return 0;
>>>>  }
>>>>  
>>>> +long p2m_set_mem_access_multi(struct domain *d,
>>>> +                              const XEN_GUEST_HANDLE(const_uint64) 
>>>> pfn_list,
>>>> +                              const XEN_GUEST_HANDLE(const_uint8) 
>>>> access_list,
>>>> +                              uint32_t nr, uint32_t start, uint32_t mask,
>>>> +                              unsigned int altp2m_idx)
>>>> +{
>>>> +    return -ENOTSUP;
>>>> +}
>>>
>>> If this indeed fixes the build problem on ARM, then I'd like to have an
>>> explanation (by you or the ARM maintainers) where ENOTSUP gets
>>> defined. I can't find any single instance of this throughout the tree,
>>> and headers outside of the tree aren't supposed to get included in
>>> the hypervisor build.
>>
>> It's defined in errno.h, which some in-tree files do include, but as
>> stated I don't, at the moment, have access to an ARM setup, so it is
>> theoretically possible that the code still doesn't compile on ARM. I
>> thought it would, since it's trivial.
> 
> I can't find any inclusion of plain errno.h (apart in tools built to aid
> the building process). There are xen/errno.h and, public/errno.h,
> but those - afaics - don't define ENOTSUP.

You're right. And yet, cross-compiling Xen for ARM64 as recommended here:

https://wiki.xenproject.org/wiki/Xen_ARM_with_Virtualization_Extensions/CrossCompiling#64-bit_crossbuild

works without a hitch.

Maybe the some standard libc header we include brings errno.h in? I'm
not sure what to do, should I switch to an error number from the in-tree
errno.h (if so, which one would be the most appropriate)?


Thanks,
Razvan

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