[dpdk-dev] [PATCH v7 2/9] eal/pci: get iommu class

[santosh]

Hi Anatoly,


On Monday 04 September 2017 08:23 PM, Burakov, Anatoly wrote:
>> From: Santosh Shukla [mailto:santosh.shukla at caviumnetworks.com]
>> Sent: Thursday, August 31, 2017 4:26 AM
>> To: dev at dpdk.org
>> Cc: thomas at monjalon.net; jerin.jacob at caviumnetworks.com;
>> hemant.agrawal at nxp.com; olivier.matz at 6wind.com;
>> maxime.coquelin at redhat.com; Gonzalez Monroy, Sergio
>> <sergio.gonzalez.monroy at intel.com>; Richardson, Bruce
>> <bruce.richardson at intel.com>; shreyansh.jain at nxp.com;
>> gaetan.rivet at 6wind.com; Burakov, Anatoly <anatoly.burakov at intel.com>;
>> stephen at networkplumber.org; aconole at redhat.com; Santosh Shukla
>> <santosh.shukla at caviumnetworks.com>
>> Subject: [PATCH v7 2/9] eal/pci: get iommu class
>>
>> Introducing rte_pci_get_iommu_class API which helps to get iommu class of
>> PCI device on the bus and returns preferred iova mapping mode for PCI bus.
>>
>> Patch also add rte_pci_get_iommu_class definition for bsdapp, in bsdapp
>> case - api returns default iova mode.
>>
>> Signed-off-by: Santosh Shukla <santosh.shukla at caviumnetworks.com>
>> Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
>> Reviewed-by: Maxime Coquelin <maxime.coquelin at redhat.com>
>> ---
>> v6 --> v7:
>> - squashed v6 series patch [02/12] & [03/12] (Aaron comment).
>>
>>  lib/librte_eal/bsdapp/eal/eal_pci.c           | 10 ++++++++++
>>  lib/librte_eal/bsdapp/eal/rte_eal_version.map |  1 +
>>  lib/librte_eal/common/include/rte_bus.h       | 10 ++++++++++
>>  lib/librte_eal/common/include/rte_pci.h       | 11 +++++++++++
>>  4 files changed, 32 insertions(+)
>>
>> diff --git a/lib/librte_eal/bsdapp/eal/eal_pci.c
>> b/lib/librte_eal/bsdapp/eal/eal_pci.c
>> index 04eacdcc7..e2c252320 100644
>> --- a/lib/librte_eal/bsdapp/eal/eal_pci.c
>> +++ b/lib/librte_eal/bsdapp/eal/eal_pci.c
>> @@ -403,6 +403,16 @@ rte_pci_scan(void)
>>  	return -1;
>>  }
>>
>> +/*
>> + * Get iommu class of pci devices on the bus.
>> + */
>> +enum rte_iova_mode
>> +rte_pci_get_iommu_class(void)
>> +{
>> +	/* Supports only RTE_KDRV_NIC_UIO */
>> +	return RTE_IOVA_PA;
>> +}
>> +
>>  int
>>  pci_update_device(const struct rte_pci_addr *addr)  { diff --git
>> a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
>> b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
>> index c819e3084..1fdcfb460 100644
>> --- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
>> +++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
>> @@ -242,5 +242,6 @@ DPDK_17.11 {
>>  	global:
>>
>>  	rte_pci_match;
>> +	rte_pci_get_iommu_class;
>>
>>  } DPDK_17.08;
>> diff --git a/lib/librte_eal/common/include/rte_bus.h
>> b/lib/librte_eal/common/include/rte_bus.h
>> index c79368d3c..9e40687e5 100644
>> --- a/lib/librte_eal/common/include/rte_bus.h
>> +++ b/lib/librte_eal/common/include/rte_bus.h
>> @@ -55,6 +55,16 @@ extern "C" {
>>  /** Double linked list of buses */
>>  TAILQ_HEAD(rte_bus_list, rte_bus);
>>
>> +
>> +/**
>> + * IOVA mapping mode.
>> + */
>> +enum rte_iova_mode {
>> +	RTE_IOVA_DC = 0,	/* Don't care mode */
>> +	RTE_IOVA_PA = (1 << 0),
>> +	RTE_IOVA_VA = (1 << 1)
> Hi Santosh,
>
> No need to set values explicitly, standard C will take care of it.

no strong opinion, change queued for v8.

> I wonder the purpose of "don't care" mode. It's not used for anything but cases when no driver is bound. All the libraries (e.g. rte_malloc) will only check for IOVA_VA mode. Can't we just used PA in all cases where IOVA_DC would be applicable?

Indeed policy is to use iova_pa for _dc case, 
but we need a way to distinguish between no device found vs device attached
(if attached then decide upon its iova scheme).

For more detailed info pl. refer [1].

[1] http://dpdk.org/dev/patchwork/patch/26762/

> Thanks,
> Anatoly