Re: [Xen-devel] [RFC 23/23] arm/xen: Add support for 64KB page granularity

[Julien Grall <julien.grall@xxxxxxxxxx>]

Hi,

On 23/06/15 15:19, Stefano Stabellini wrote:
>> diff --git a/arch/arm/xen/enlighten.c b/arch/arm/xen/enlighten.c
>> index 224081c..dcfe251 100644
>> --- a/arch/arm/xen/enlighten.c
>> +++ b/arch/arm/xen/enlighten.c
>> @@ -93,8 +93,8 @@ static void xen_percpu_init(void)
>>      pr_info("Xen: initializing cpu%d\n", cpu);
>>      vcpup = per_cpu_ptr(xen_vcpu_info, cpu);
>>  
>> -    info.mfn = __pa(vcpup) >> PAGE_SHIFT;
>> -    info.offset = offset_in_page(vcpup);
>> +    info.mfn = __pa(vcpup) >> XEN_PAGE_SHIFT;
>> +    info.offset = xen_offset_in_page(vcpup);
>>  
>>      err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, cpu, &info);
>>      BUG_ON(err);
>> @@ -204,7 +204,7 @@ static int __init xen_guest_init(void)
>>      xatp.domid = DOMID_SELF;
>>      xatp.idx = 0;
>>      xatp.space = XENMAPSPACE_shared_info;
>> -    xatp.gpfn = __pa(shared_info_page) >> PAGE_SHIFT;
>> +    xatp.gpfn = __pa(shared_info_page) >> XEN_PAGE_SHIFT;
>>      if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
>>              BUG();
> 
> What about xen_remap_domain_mfn_range? I guess we don't support that use
> case on 64K guests? If so, I would appreaciate an assert and/or an error
> message.

The implementation of xen_remap_domain_mfn_range return -ENOSYS no
matter the page granularity.

This function is PV specific and has been added few months ago just for
a stub. See comment in the code:
"/* Not used by XENFEAT_auto_translated guests */"

Any logging/BUG_ON within this function is out of scope for this series.
And I don't think this will be really useful. Feel free to send a patch
for it.

Regards,

-- 
Julien Grall

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