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

Eelco Chaudron echaudro at redhat.com
Tue Jul 10 12:06:29 CEST 2018



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?

>>> +
>>> +               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
>>>
>>




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