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

Sergio Gonzalez Monroy sergio.gonzalez.monroy at intel.com
Wed Jul 12 10:20:03 CEST 2017


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?

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;
>   




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