On Tue, Jul 10, 2018 at 12:33 PM, Burakov, Anatoly <
anatoly.bura...@intel.com> wrote:
> On 10-Jul-18 12:14 PM, Eelco Chaudron wrote:
>
>>
>>
>> On 10 Jul 2018, at 12:52, Alejandro Lucero wrote:
>>
>> On Tue, Jul 10, 2018 at 11:06 AM, Eelco Chaudron <echau...@redhat.com>
>>> wrote:
>>>
>>>
>>>>
>>>> On 10 Jul 2018, at 11:34, Alejandro Lucero wrote:
>>>>
>>>> On Tue, Jul 10, 2018 at 9:56 AM, Eelco Chaudron <echau...@redhat.com>
>>>>
>>>>> wrote:
>>>>>
>>>>>
>>>>>
>>>>>> On 4 Jul 2018, at 14:53, Alejandro Lucero wrote:
>>>>>>
>>>>>> A device can suffer addressing limitations. This functions checks
>>>>>>
>>>>>> memsegs have iovas within the supported range based on dma mask.
>>>>>>>
>>>>>>> PMD should use this during initialization if supported devices
>>>>>>> suffer addressing limitations, returning an error if this function
>>>>>>> returns memsegs out of range.
>>>>>>>
>>>>>>> Another potential usage is for emulated IOMMU hardware with
>>>>>>> addressing
>>>>>>> limitations.
>>>>>>>
>>>>>>> Signed-off-by: Alejandro Lucero <alejandro.luc...@netronome.com>
>>>>>>> Acked-by: Anatoly Burakov <anatoly.bura...@intel.com>
>>>>>>> ---
>>>>>>> lib/librte_eal/common/eal_common_memory.c | 33
>>>>>>> ++++++++++++++++++++++++++++++
>>>>>>> lib/librte_eal/common/include/rte_memory.h | 3 +++
>>>>>>> lib/librte_eal/rte_eal_version.map | 1 +
>>>>>>> 3 files changed, 37 insertions(+)
>>>>>>>
>>>>>>> diff --git a/lib/librte_eal/common/eal_common_memory.c
>>>>>>> b/lib/librte_eal/common/eal_common_memory.c
>>>>>>> index fc6c44d..f5efebe 100644
>>>>>>> --- a/lib/librte_eal/common/eal_common_memory.c
>>>>>>> +++ b/lib/librte_eal/common/eal_common_memory.c
>>>>>>> @@ -109,6 +109,39 @@
>>>>>>> }
>>>>>>> }
>>>>>>>
>>>>>>> +/* check memseg iovas are within the required range based on dma
>>>>>>> mask
>>>>>>> */
>>>>>>> +int
>>>>>>> +rte_eal_check_dma_mask(uint8_t maskbits)
>>>>>>> +{
>>>>>>> +
>>>>>>> + const struct rte_mem_config *mcfg;
>>>>>>> + uint64_t mask;
>>>>>>> + int i;
>>>>>>> +
>>>>>>>
>>>>>>>
>>>>>>> I think we should add some sanity check to the input maskbits, i.e.
>>>>>> [64,0)
>>>>>> or [64, 32]? What would be a reasonable lower bound.
>>>>>>
>>>>>>
>>>>>> This is not a user's API, so any invocation will be reviewed, but I
>>>>>> guess
>>>>>>
>>>>> adding a sanity check here does not harm.
>>>>>
>>>>> Not sure about lower bound but upper should 64, although it does not
>>>>> make
>>>>> sense but it is safe. Lower bound is not so problematic.
>>>>>
>>>>>
>>>>>
>>>>> + /* create dma mask */
>>>>>>
>>>>>> + mask = ~((1ULL << maskbits) - 1);
>>>>>>> +
>>>>>>> + /* get pointer to global configuration */
>>>>>>> + mcfg = rte_eal_get_configuration()->mem_config;
>>>>>>> +
>>>>>>> + for (i = 0; i < RTE_MAX_MEMSEG; i++) {
>>>>>>> + if (mcfg->memseg[i].addr == NULL)
>>>>>>> + break;
>>>>>>>
>>>>>>>
>>>>>> Looking at some other code, it looks like NULL entries might exists.
>>>> So
>>>> should a continue; rather than a break; be used here?
>>>>
>>>>
>>>> I do not think so. memsegs are allocated sequentially, so first with
>>> addr
>>> as NULL implies no more memsegs.
>>>
>>
>> I was referring to the mem walk functions, rte_memseg_list_walk(). Maybe
>> some having more experience with this area can review/comment.
>>
>
> Pre-18.05, all memsegs are allocated continuously. Memseg lists and memseg
> list walk functions are 18.05+.
>
> Alejandro, perhaps it would be worth it to tag your patchset with
> "pre-18.05" to avoid similar confusion in the future?
>
>
Yes, that will help. I'm sending a new version shortly and I'll make it
clear.
> --
> Thanks,
> Anatoly
>
