Re: [PATCH 6/6] xen: arm: use superpages in p2m when pages are suitably aligned

[Julien Grall <julien.grall@linaro.org>]

On 10/06/14 16:23, Ian Campbell wrote:
> On Tue, 2014-06-10 at 13:10 +0100, Julien Grall wrote:
>> Hi Ian,
>>
>> This patch looks good in general. I've only few comments, see them below.
>>
>> On 06/10/2014 10:57 AM, Ian Campbell wrote:
>>> +void p2m_dump_info(struct domain *d)
>>> +{
>>> +    struct p2m_domain *p2m = &d->arch.p2m;
>>> +
>>> +    spin_lock(&p2m->lock);
>>> +    printk("p2m mappings for domain %d (vmid %d):\n",
>>> +           d->domain_id, p2m->vmid);
>>> +    BUG_ON(p2m->stats.mappings[0] || p2m->stats.shattered[0]);
>>> +    printk("  1G mappings: %d (shattered %d)\n",
>>> +           p2m->stats.mappings[1], p2m->stats.shattered[1]);
>>> +    printk("  2M mappings: %d (shattered %d)\n",
>>> +           p2m->stats.mappings[2], p2m->stats.shattered[2]);
>>> +    printk("  4K mappings: %d\n", p2m->stats.mappings[3]);
>>
>> I wondering if we can have more than 2^32-1 4K mapping sometimes...
>
> That would be 16TB of memory, which isn't out of the question but we
> don't currently support it. Still, not much harm in increase to a 64-bit
> field.

Sounds good.

>> I think we should document how we pass the argument to apply_p2m_changes
>> somewhere. Even better, use gmfn and nr_gfn, as x86 does, for
>> apply_p2m_changes and handle internally the pfn_to_paddr stuff. This
>> would avoid this kind of problem.
>
> Arianna is sorting that all out in her mmio mapping series.

Oh right. Some of you will have to rebase his/her series on top of the 
other one :).

Regards,

-- 
Julien Grall