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

[santosh]

Hi Sergio,

On Friday 14 July 2017 01:13 PM, Sergio Gonzalez Monroy wrote:

> On 13/07/2017 09:23, santosh wrote:
>> Hi Sergio,
>>
>> On Wednesday 12 July 2017 01:50 PM, Sergio Gonzalez Monroy wrote:
>>
>>> On 11/07/2017 07:16, 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
>>> Just wondering how it all works with device hotplug.
>>> Correct me if I am wrong but if EAL decides to use IOVA_AS_VA scheme,
>>> if we were to attach a device that needs IOVA_AS_PA, it will not work and should fail to attach, right?
>>>
>> It will work for igb_uio case, and won't work for vfio-noiommu hotplug case(Invalid case).
>
> Why are those two cases (igb_uio, vfio-noiommu) different? do they not have the same requirements, ie. need IOVA_PA sheme?
>
Behavior remains same.

For vfio-noiommu case in the context of hot-plugging - Rest of the VFIO(/iommu) devices will be functionally
effected thats why mentioned invalid case.

> Thanks,
> Sergio
>
>> Yes, we can dictate iova awareness to hotplug/unplug area.
>>
>>> Thanks,
>>> Sergio
>>>
>>>>    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;
>>>> +
>>>> +    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;
>>>>    
>>>
>