[dpdk-stable] [PATCH v3 2/6] ethdev: add function for checking IOVAs by a device

[Alejandro Lucero]

On Tue, Jul 10, 2018 at 10:42 AM, Alejandro Lucero <
alejandro.lucero at netronome.com> wrote:

>
>
> On Tue, Jul 10, 2018 at 9:57 AM, Eelco Chaudron <echaudro at redhat.com>
> wrote:
>
>>
>>
>> On 4 Jul 2018, at 14:53, Alejandro Lucero wrote:
>>
>> A PMD should invoke this function for checking memsegs iovas are within
>>> the supported range by the device.
>>>
>>> Signed-off-by: Alejandro Lucero <alejandro.lucero at netronome.com>
>>>
>>
>> Agree with Andrew here, why not call rte_eal_check_dma_mask() directly in
>> nfp_net_txq_full()?
>>
>>
BTW, IOVA checking can not be done inside PMD functions like that one
because that is in the fast path. Any IOVA checking needs to be done at
initialization time.


>
> My idea was to add this indirection for handling dma mask when just part
> of the IOVAs are not usable. Now, if the dma mask finds a problem, the PMD
> does not make any port initialization.
>
> Memory management is changing and ideally an app should just allocate
> memory safe to be used by the PMD when that memory is going to be used for
> sending or receiving data, what is not always the case.
>
> It is true this indirection is not being used for any purpose by now, so
> yes, I could use a direct call the the EAL one.
>
>
>>
>> ---
>>>  lib/librte_ether/rte_ethdev.h           | 13 +++++++++++++
>>>  lib/librte_ether/rte_ethdev_version.map |  1 +
>>>  2 files changed, 14 insertions(+)
>>>
>>> diff --git a/lib/librte_ether/rte_ethdev.h
>>> b/lib/librte_ether/rte_ethdev.h
>>> index eba11ca..e51a432 100644
>>> --- a/lib/librte_ether/rte_ethdev.h
>>> +++ b/lib/librte_ether/rte_ethdev.h
>>> @@ -2799,6 +2799,19 @@ int rte_eth_dev_set_vlan_ether_type(uint16_t
>>> port_id,
>>>  int rte_eth_dev_set_vlan_pvid(uint16_t port_id, uint16_t pvid, int on);
>>>
>>>  /**
>>> + * check device dma mask within expected range based on dma mask.
>>> + *
>>> + * @param maskbits
>>> + *  mask length in bits
>>> + *
>>> + */
>>> +static inline int
>>> +rte_eth_dev_check_dma_mask(uint8_t maskbits)
>>> +{
>>> +       return rte_eal_check_dma_mask(maskbits);
>>> +}
>>> +
>>> +/**
>>>   *
>>>   * Retrieve a burst of input packets from a receive queue of an Ethernet
>>>   * device. The retrieved packets are stored in *rte_mbuf* structures
>>> whose
>>> diff --git a/lib/librte_ether/rte_ethdev_version.map
>>> b/lib/librte_ether/rte_ethdev_version.map
>>> index e9681ac..0b11b8a 100644
>>> --- a/lib/librte_ether/rte_ethdev_version.map
>>> +++ b/lib/librte_ether/rte_ethdev_version.map
>>> @@ -191,6 +191,7 @@ DPDK_17.08 {
>>>  DPDK_17.11 {
>>>         global:
>>>
>>> +       rte_eth_dev_check_dma_mask;
>>>         rte_eth_dev_get_sec_ctx;
>>>         rte_eth_dev_pool_ops_supported;
>>>         rte_eth_dev_reset;
>>> --
>>> 1.9.1
>>>
>>
>