Re: [Xen-devel] VMX status report. Xen:26323 & Dom0:3.7.1

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 14.01.13 at 17:03, David Vrabel <david.vrabel@xxxxxxxxxx> wrote:
> On 14/01/13 15:06, Andres Lagar-Cavilla wrote:
>> @@ -288,7 +289,19 @@ static int mmap_batch_fn(void *data, void *state)
>>                                       &cur_page);
>>  
>>      /* Store error code for second pass. */
>> -    *(st->err++) = ret;
>> +    if (st->version == 1) {
>> +            if (ret < 0) {
>> +                    /*
>> +                     * V1 encodes the error codes in the 32bit top nibble 
>> of the
>> +                     * mfn (with its known limitations vis-a-vis 64 bit 
>> callers).
>> +                     */
>> +                    *mfnp |= (ret == -ENOENT) ?
>> +                                            PRIVCMD_MMAPBATCH_PAGED_ERROR :
>> +                                            PRIVCMD_MMAPBATCH_MFN_ERROR;
> 
> You also need to clear the top nibble on success (ret >= 0) so large
> PFNs with the top nibble already set don't give false positives of errors.

Not really - that's what v2 was added for (the caller, unless
keeping a second array with the original MFNs, wouldn't be able
to match things up in that case).

Jan


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