[dpdk-dev] Issue with VFIO/IOMMU
Vikas Gupta
vikas.gupta at broadcom.com
Mon Sep 7 15:31:10 CEST 2020
RE: [dpdk-dev] Issue with VFIO/IOMMU
Hi Burakov,
-----Original Message-----
From: Burakov, Anatoly [mailto:anatoly.burakov at intel.com
<anatoly.burakov at intel.com>]
Sent: Friday, September 04, 2020 7:20 PM
To: Vikas Gupta <vikas.gupta at broadcom.com>; dev at dpdk.org
Cc: Ajit Kumar Khaparde <ajit.khaparde at broadcom.com>; Vikram Prakash <
vikram.prakash at broadcom.com>
Subject: Re: [dpdk-dev] Issue with VFIO/IOMMU
On 03-Sep-20 12:09 PM, Vikas Gupta wrote:
> Hi,
>
> I observe an issue with IOVA address returned by api
> rte_memzone_reserve_aligned (flags= RTE_MEMZONE_IOVA_CONTIG) used for
> queue memory allocation. With high level debugging, I notice that IOVA
> address returned in mz->iova is not mapped by VFIO_IOMMU_MAP_DMA so in
> turn SMMU exception is seen.
I'm not sure i follow.
How did you determine that to be the case, given that, by your own
admission below, `vfio_type1_dma_mem_map` function is executed several
times?
[Vikas]:
I`ll mention map and unmap as below in explaining through one of the example
map = function vfio_type1_dma_mem_map called with argument do_map = 1
unamp = function type1_dma_mem_map called with argument do_map = 0
What I notice that for some particular address received in mz->iova, after
rte_memzone_reserve_aligned is successfully returned, the map function
(vfio_type1_dma_mem_map do_map =1) was not called prior to return of
function rte_memzone_reserve_aligned.
Below is one of the sequence to understand.
Let’s say there is an address ‘*iova_fail’*, for which exception is raised
by SMMU while dpdk-test runs with Crypto PMD.
When dpdk-test is run with Crypto test suit I see that for an address*
iova_fail* several times vfio_type1_dma_mem_map is called with (do_map =
0/1 with length = 2MB). I believe this happens due to call for memory
allocation/free for buffers/queues. The test runs fine as long as the map
is called before rte_memzone_reserve_aligned returns and similarly for
unmap when same memory is freed. But after several times with map/unmap for*
iova_fail*, map is NOT called before rte_memzone_reserve_aligned is retuned
though iova_fail was previously unmapped. Since it’s not mapped, SMMU
raises an exception.
Please note issue is not frequently visible and might reproduce after
pmd_crypto_autotest is run multiple times over dpdk-test.
If you are not able to follow I`ll try to send the debug printfs for test.
Thanks,
Vikas
>
>
>
> *Details for the setup*
>
> Platform: Armv8 (Broadcom Stingray)
>
> DPDK release: DPDK 20.08 <http://fast.dpdk.org/rel/dpdk-20.08.tar.xz>
>
> PMD patch:
>
> https://patches.dpdk.org/project/dpdk/list/?series=&submitter=1907&sta
> te=&q=&archive=&delegate=
>
> dpdk-test is launched using below command
>
> *dpdk-test --vdev <cryptopmd_name> -w 0000:00:00.0 --iova-mode pa *
>
>
>
> The test suite is launched over dpdk-test application command prompt
> using command ‘cryptodev_<cryptopmd_name>_autotest’
>
> The issue is seen when several iterations of above test_suite is
> executed which in turn do multiple calls to
> rte_memzone_reserve_aligned, rte_mempool_create and rte_memzone_free,
rte_mempool_free.
>
> Function *vfio_type1_dma_mem_map* with map/unmap event is executed
> several times during test_suite run.
>
>
>
> Any inputs would be helpful.
>
>
>
> Thanks,
>
> Vikas
>
--
Thanks,
Anatoly
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