[dpdk-dev] [PATCH 1/2] eal: honor IOVA mode for no-huge case

[Ferruh Yigit]

On 10/31/2017 3:37 PM, Ferruh Yigit wrote:
> On 10/31/2017 2:49 PM, Ferruh Yigit wrote:
>> On 10/11/2017 3:33 AM, Jianfeng Tan wrote:
>>> With the introduction of IOVA mode, the only blocker to run
>>> with 4KB pages for NICs binding to vfio-pci, is that
>>> RTE_BAD_PHYS_ADDR is not a valid IOVA address.
>>>
>>> We can refine this by using VA as IOVA if it's IOVA mode.
>>>
>>> Signed-off-by: Jianfeng Tan <jianfeng.tan at intel.com>
>>> ---
>>>  lib/librte_eal/linuxapp/eal/eal_memory.c | 5 ++++-
>>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/librte_eal/linuxapp/eal/eal_memory.c b/lib/librte_eal/linuxapp/eal/eal_memory.c
>>> index 28bca49..187d338 100644
>>> --- a/lib/librte_eal/linuxapp/eal/eal_memory.c
>>> +++ b/lib/librte_eal/linuxapp/eal/eal_memory.c
>>> @@ -1030,7 +1030,10 @@ rte_eal_hugepage_init(void)
>>>  					strerror(errno));
>>>  			return -1;
>>>  		}
>>> -		mcfg->memseg[0].phys_addr = RTE_BAD_PHYS_ADDR;
>>> +		if (rte_eal_iova_mode() == RTE_IOVA_VA)
>>> +			mcfg->memseg[0].phys_addr = (uintptr_t)addr;
>>> +		else
>>> +			mcfg->memseg[0].phys_addr = RTE_BAD_PHYS_ADDR;
>>
>> This breaks KNI which requires physical address.
> 
> My bad, this patch is for no_hugetlbfs case.
> 
> Issue seen starting from next patch in the set [1], which enables IOVA mode for
> Intel PMDs.
> 
> With IOVA mode enabled, KNI fails.
> 
> Does it make sense to add an API to set iova mode explicitly by application?
> Application can set iova to PA and allocate memzones it requires.

Added config option to disable IOVA mode detection:
http://dpdk.org/dev/patchwork/patch/31071/

Still concerned if this may hit someone, since the result for KNI is a kernel
crash it would be nice to have more solid protection here.

And suggestion welcome.

Thanks,
ferruh

> 
> [1]
> http://dpdk.org/commit/f37dfab2
> 
>>
>> Any idea how to disable RTE_IOVA_VA when KNI used?
>>
>>>  		mcfg->memseg[0].addr = addr;
>>>  		mcfg->memseg[0].hugepage_sz = RTE_PGSIZE_4K;
>>>  		mcfg->memseg[0].len = internal_config.memory;
>>>
>>
>