[dpdk-dev] [PATCH v3 04/11] linuxapp/eal_pci: get iommu class

[santosh]

On Friday 14 July 2017 01:09 PM, Hemant Agrawal wrote:

> On 7/11/2017 11:46 AM, Santosh Shukla wrote:
>> Get iommu class of PCI device on the bus and returns preferred iova
>> mapping mode for that bus.
>>
>> Algorithm for iova scheme selection for PCI bus:
>> 0. Look for device attached to vfio kdrv and has .drv_flag set
>> to RTE_PCI_DRV_NEED_IOVA_VA.
>> 1. Look for any device attached to UIO class of driver.
>> 2. Check for vfio-noiommu mode enabled.
>>
>> If 1) & 2) is false and 0) is true then select
>> mapping scheme as iova=va. Otherwise use default
>> mapping scheme (iova_pa).
>>
>> Signed-off-by: Santosh Shukla <santosh.shukla at caviumnetworks.com>
>> Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
>> ---
>> v1 --> v2:
>> - Removed Linux version check in vfio_noiommu func. Refer [1].
>> - Extending autodetction logic for _iommu_class.
>> Refer [2].
>>
>> [1] https://www.mail-archive.com/dev@dpdk.org/msg70108.html
>> [2] https://www.mail-archive.com/dev@dpdk.org/msg70279.html
>>
>>  lib/librte_eal/linuxapp/eal/eal_pci.c           | 66 +++++++++++++++++++++++++
>>  lib/librte_eal/linuxapp/eal/eal_vfio.c          | 19 +++++++
>>  lib/librte_eal/linuxapp/eal/eal_vfio.h          |  4 ++
>>  lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
>>  4 files changed, 90 insertions(+)
>>
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_pci.c b/lib/librte_eal/linuxapp/eal/eal_pci.c
>> index 7d9e1a99b..573caa000 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_pci.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_pci.c
>> @@ -45,6 +45,7 @@
>>  #include "eal_filesystem.h"
>>  #include "eal_private.h"
>>  #include "eal_pci_init.h"
>> +#include "eal_vfio.h"
>>
>>  /**
>>   * @file
>> @@ -488,6 +489,71 @@ rte_pci_scan(void)
>>      return -1;
>>  }
>>
>> +/*
>> + * Any one of the device bound to uio
>> + */
>> +static inline int
>> +pci_device_bound_uio(void)
>> +{
>> +    struct rte_pci_device *dev = NULL;
>> +
>> +    FOREACH_DEVICE_ON_PCIBUS(dev) {
>> +        if (dev->kdrv == RTE_KDRV_IGB_UIO ||
>> +           dev->kdrv == RTE_KDRV_UIO_GENERIC) {
>> +            return 1;
>> +        }
>> +    }
>> +    return 0;
>> +}
>> +
>> +/*
>> + * Any one of the device has iova as va
>> + */
>> +static inline int
>> +pci_device_has_iova_va(void)
>> +{
>> +    struct rte_pci_device *dev = NULL;
>> +    struct rte_pci_driver *drv = NULL;
>> +
>> +    FOREACH_DRIVER_ON_PCIBUS(drv) {
>> +        if (drv && drv->drv_flags & RTE_PCI_DRV_NEED_IOVA_VA) {
>> +            FOREACH_DEVICE_ON_PCIBUS(dev) {
>> +                if (dev->kdrv == RTE_KDRV_VFIO &&
>> +                    rte_pci_match(drv, dev))
>> +                    return 1;
>> +            }
>> +        }
>> +    }
>> +    return 0;
>> +}
>> +
>> +/*
>> + * Get iommu class of PCI devices on the bus.
>> + */
>> +enum rte_iova_mode
>> +rte_pci_get_iommu_class(void)
>> +{
>> +    bool is_vfio_noiommu_enabled;
>> +    bool has_iova_va;
>> +    bool is_bound_uio;
>> +
>> +    has_iova_va = pci_device_has_iova_va();
>> +    is_bound_uio = pci_device_bound_uio();
>> +    is_vfio_noiommu_enabled = vfio_noiommu_is_enabled() == 1 ? 1 : 0;
>> +
>> +    if (has_iova_va && !is_bound_uio && !is_vfio_noiommu_enabled)
>> +        return RTE_IOVA_VA;
>> +
>
> PCI is generally present in all platform including dpaa2.
> There may not be any device found or available for dpdk usages in such cases. The PCI bus will still return RTE_IOVA_PA, which will make the system mode as PA.
>
That's the expected behavior. And implementation makes sure
that PCI_bus return default mode aka _PA if no-pci device found.

Isn't code taking care of same?

Let me walk through the code:

has_iova_va = 0 (if no pci device then pci_device_has_iov_va() will return 0).

And if (has_iova_va & ,,,) will fail therefore rte_pci_get_iommu_class() retuns RTE_IOVA_PA mode.
which is default mode. Right?

>> +    if (has_iova_va) {
>> +        if (is_vfio_noiommu_enabled)
>> +            RTE_LOG(WARNING, EAL, "vfio-noiommu mode configured\n");
>> +        if (is_bound_uio)
>> +            RTE_LOG(WARNING, EAL, "Some device attached to UIO\n");
>> +    }
>> +
>> +    return RTE_IOVA_PA;
>> +}
>> +
>>  /* Read PCI config space. */
>>  int rte_pci_read_config(const struct rte_pci_device *device,
>>          void *buf, size_t len, off_t offset)
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.c b/lib/librte_eal/linuxapp/eal/eal_vfio.c
>> index 946df7e31..c8a97b7e7 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_vfio.c
>> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio.c
>> @@ -816,4 +816,23 @@ vfio_noiommu_dma_map(int __rte_unused vfio_container_fd)
>>      return 0;
>>  }
>>
>> +int
>> +vfio_noiommu_is_enabled(void)
>> +{
>> +    int fd, ret, cnt __rte_unused;
>> +    char c;
>> +
>> +    ret = -1;
>> +    fd = open(VFIO_NOIOMMU_MODE, O_RDONLY);
>> +    if (fd < 0)
>> +        return -1;
>> +
>> +    cnt = read(fd, &c, 1);
>> +    if (c == 'Y')
>> +        ret = 1;
>> +
>> +    close(fd);
>> +    return ret;
>> +}
>> +
>>  #endif
>> diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio.h b/lib/librte_eal/linuxapp/eal/eal_vfio.h
>> index 5ff63e5d7..26ea8e119 100644
>> --- a/lib/librte_eal/linuxapp/eal/eal_vfio.h
>> +++ b/lib/librte_eal/linuxapp/eal/eal_vfio.h
>> @@ -150,6 +150,8 @@ struct vfio_config {
>>  #define VFIO_NOIOMMU_GROUP_FMT "/dev/vfio/noiommu-%u"
>>  #define VFIO_GET_REGION_ADDR(x) ((uint64_t) x << 40ULL)
>>  #define VFIO_GET_REGION_IDX(x) (x >> 40)
>> +#define VFIO_NOIOMMU_MODE      \
>> +    "/sys/module/vfio/parameters/enable_unsafe_noiommu_mode"
>>
>>  /* DMA mapping function prototype.
>>   * Takes VFIO container fd as a parameter.
>> @@ -210,6 +212,8 @@ int pci_vfio_is_enabled(void);
>>
>>  int vfio_mp_sync_setup(void);
>>
>> +int vfio_noiommu_is_enabled(void);
>> +
>>  #define SOCKET_REQ_CONTAINER 0x100
>>  #define SOCKET_REQ_GROUP 0x200
>>  #define SOCKET_CLR_GROUP 0x300
>> diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
>> index c91dd44c4..044f89c7c 100644
>> --- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
>> +++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
>> @@ -206,6 +206,7 @@ DPDK_17.08 {
>>      rte_bus_find_by_device;
>>      rte_bus_find_by_name;
>>      rte_pci_match;
>> +    rte_pci_get_iommu_class;
>>
>>  } DPDK_17.05;
>>
>>
>
>