Re: [v5][PATCH 1/2] xen:x86:mm:p2m: introduce set_identity_p2m_entry

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 29/07/2014 09:19, Jan Beulich wrote:
>>>> On 29.07.14 at 09:35, <tiejun.chen@intel.com> wrote:
>> On 2014/7/29 15:05, Jan Beulich wrote:
>>>>>> On 29.07.14 at 08:40, <tiejun.chen@intel.com> wrote:
>>>> +    struct p2m_domain *p2m = p2m_get_hostp2m(d);
>>>> +    int ret = -EBUSY;
>>>> +
>>>> +    gfn_lock(p2m, gfn, 0);
>>>> +
>>>> +    tmp_mfn = p2m->get_entry(p2m, gfn, &p2mt, &a, 0, NULL);
>>>> +
>>>> +    if ( mfn_valid(tmp_mfn) )
>>>> +    {
>>>> +        gdprintk(XENLOG_ERR,
>>>> +                 "Overlapping RMRRs at %"PRIx64".\n", (paddr_t)gfn);
>>> Pointless cast: Just use %lx in the format string. Additionally I don't
>>> think the message text is correct: You don't really know whether
>>> what's there is another RMRR (or that the context you're being
>>> called in refers to an RMRR at all). On the contrary - if it was an
>>> RMRR (or to be precise, a previously established identity mapping),
>>> you'd want to report success. And generally we have no stop at
>>> the end of log messages.
>> So just print this,
>>
>> +        gdprintk(XENLOG_ERR,
>> +                 "Overlapping at %lx.\n", (paddr_t)gfn);
> Of course not - such a message is really meaningless.
>
> printk(XENLOG_G_WARNING "Cannot identity map %d:%lx, already mapped to %lx\n",
>        d->domain_id, gfn, mfn_x(mfn));
>
> would be a message conveying all information necessary to
> gain initial understanding of what the issue is.

This would be better as "map d%d:%lx" to indicate that it is a domid
before the colon.

~Andrew