[dpdk-stable] [PATCH v3 1/6] mem: add function for checking memsegs IOVAs addresses

[Alejandro Lucero]

On Tue, Jul 10, 2018 at 12:14 PM, Eelco Chaudron <echaudro at redhat.com>
wrote:

>
>
> On 10 Jul 2018, at 12:52, Alejandro Lucero wrote:
>
> On Tue, Jul 10, 2018 at 11:06 AM, Eelco Chaudron <echaudro at redhat.com>
>> wrote:
>>
>>
>>>
>>> On 10 Jul 2018, at 11:34, Alejandro Lucero wrote:
>>>
>>> On Tue, Jul 10, 2018 at 9:56 AM, Eelco Chaudron <echaudro at 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.lucero at netronome.com>
>>>>>> Acked-by: Anatoly Burakov <anatoly.burakov at 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.
>
>
This patchset applies to 17.11.3 which has not that function implemented.

You can see what rte_eal_get_physmem_size and rte_dump_physmem_layout do in
lib/librte_eal/common/eal_common_memory.c file regarding memseg "walks"
when addr is NULL.




>
>
>>
>>
>>> +
>>>
>>>> +               if (mcfg->memseg[i].iova & mask) {
>>>>>> +                       RTE_LOG(INFO, EAL,
>>>>>> +                               "memseg[%d] iova %"PRIx64" out of
>>>>>> range:\n",
>>>>>> +                               i, mcfg->memseg[i].iova);
>>>>>> +
>>>>>> +                       RTE_LOG(INFO, EAL, "\tusing dma mask
>>>>>> %"PRIx64"\n",
>>>>>> +                               mask);
>>>>>> +                       return -1;
>>>>>> +               }
>>>>>> +       }
>>>>>> +
>>>>>> +       return 0;
>>>>>> +}
>>>>>> +
>>>>>>  /* return the number of memory channels */
>>>>>>  unsigned rte_memory_get_nchannel(void)
>>>>>>  {
>>>>>> diff --git a/lib/librte_eal/common/include/rte_memory.h
>>>>>> b/lib/librte_eal/common/include/rte_memory.h
>>>>>> index 80a8fc0..b2a0168 100644
>>>>>> --- a/lib/librte_eal/common/include/rte_memory.h
>>>>>> +++ b/lib/librte_eal/common/include/rte_memory.h
>>>>>> @@ -209,6 +209,9 @@ struct rte_memseg {
>>>>>>   */
>>>>>>  unsigned rte_memory_get_nrank(void);
>>>>>>
>>>>>> +/* check memsegs iovas are within a range based on dma mask */
>>>>>> +int rte_eal_check_dma_mask(uint8_t maskbits);
>>>>>> +
>>>>>>  /**
>>>>>>   * Drivers based on uio will not load unless physical
>>>>>>   * addresses are obtainable. It is only possible to get
>>>>>> diff --git a/lib/librte_eal/rte_eal_version.map
>>>>>> b/lib/librte_eal/rte_eal_version.map
>>>>>> index f4f46c1..aa6cf87 100644
>>>>>> --- a/lib/librte_eal/rte_eal_version.map
>>>>>> +++ b/lib/librte_eal/rte_eal_version.map
>>>>>> @@ -184,6 +184,7 @@ DPDK_17.11 {
>>>>>>
>>>>>>         rte_eal_create_uio_dev;
>>>>>>         rte_bus_get_iommu_class;
>>>>>> +       rte_eal_check_dma_mask;
>>>>>>         rte_eal_has_pci;
>>>>>>         rte_eal_iova_mode;
>>>>>>         rte_eal_mbuf_default_mempool_ops;
>>>>>> --
>>>>>> 1.9.1
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>
>>>
>
>