Re: [dpdk-dev] [PATCH v2 5/7] mem: modify error message for DMA mask check

["Burakov, Anatoly" <anatoly.burakov@intel.com>]

On 05-Nov-18 10:13 AM, Alejandro Lucero wrote:
> On Mon, Nov 5, 2018 at 10:01 AM Li, WenjieX A <wenjiex.a.li@intel.com>
> wrote:
> 
>> 1. With GCC32, testpmd could not startup without '--iova-mode pa'.
>> ./i686-native-linuxapp-gcc/app/testpmd -c f -n 4 -- -i
>> The output is:
>> EAL: Detected 16 lcore(s)
>> EAL: Detected 1 NUMA nodes
>> EAL: Multi-process socket /var/run/dpdk/rte/mp_socket
>> EAL: Some devices want iova as va but pa will be used because.. EAL: few
>> device bound to UIO
>> EAL: No free hugepages reported in hugepages-1048576kB
>> EAL: Probing VFIO support...
>> EAL: VFIO support initialized
>> EAL: wrong dma mask size 48 (Max: 31)
>> EAL: alloc_pages_on_heap(): couldn't allocate memory due to IOVA exceeding
>> limits of current DMA mask
>> error allocating rte services array
>> EAL: FATAL: rte_service_init() failed
>> EAL: rte_service_init() failed
>> PANIC in main():
>> Cannot init EAL
>> 5: [./i686-native-linuxapp-gcc/app/testpmd(+0x95fda) [0x56606fda]]
>> 4: [/lib/i386-linux-gnu/libc.so.6(__libc_start_main+0xf6) [0xf74d1276]]
>> 3: [./i686-native-linuxapp-gcc/app/testpmd(main+0xf21) [0x565fcee1]]
>> 2: [./i686-native-linuxapp-gcc/app/testpmd(__rte_panic+0x3d) [0x565edc68]]
>> 1: [./i686-native-linuxapp-gcc/app/testpmd(rte_dump_stack+0x33)
>> [0x5675f333]]
>> Aborted
>>
>> 2. With '--iova-mode pa', testpmd could startup.
>> 3. With GCC64, there is no such issue.
>> Thanks!
>>
>>
> Does 32 bits support require IOMMU? It would be a surprise. If there is no
> IOMMU hardware, no dma mask should be there at all.

IOMMU is supported on 32-bits, however limited the address space might 
be. Maybe limit IOMMU width to RTE_MIN(31, value) bits for everything on 
32-bit?

-- 
Thanks,
Anatoly