Re: [Xen-devel] [PATCH v3 1/5] move XENMEM_add_to_physmap handling framework to common code

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 20.12.13 at 13:26, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:
> On 20/12/13 10:41, Jan Beulich wrote:
>> +        case XENMEM_add_to_physmap:
>> +            if ( !rc || cmp.atp.space != XENMAPSPACE_gmfn_range )
>> +                break;
> 
> Why is this check here in the compat layer?  Surely the -ENOSYS from
> do_memory_op is sufficient to be included in the !rc check ?
> 
>> +
>> +            XLAT_add_to_physmap(&cmp.atp, nat.atp);
>> +            if ( __copy_to_guest(compat, &cmp.atp, 1) )
>> +                rc = -EFAULT;
>> +
>> +            break;

You mis-read the meaning of the check: The reverse translation
was necessary (it's gone with patch 2 anyway) only when
wanting to copy back into the interface structure. Since that
code is gone with us no longer doing these invalid modifications,
any possible incorrectness here is moot now anyway.

Jan


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