Re: [dpdk-dev] [PATCH v4 02/44] bus/vdev: add driver IOVA VA mode requirement

["Xia, Chenbo" <chenbo.xia@intel.com>]

> -----Original Message-----
> From: Maxime Coquelin <maxime.coquelin@redhat.com>
> Sent: Tuesday, January 26, 2021 6:16 PM
> To: dev@dpdk.org; Xia, Chenbo <chenbo.xia@intel.com>; olivier.matz@6wind.com;
> amorenoz@redhat.com; david.marchand@redhat.com
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
> Subject: [PATCH v4 02/44] bus/vdev: add driver IOVA VA mode requirement
> 
> This patch adds driver flag in vdev bus driver so that
> vdev drivers can require VA IOVA mode to be used, which
> for example the case of Virtio-user PMD.
> 
> The patch implements the .get_iommu_class() callback, that
> is called before devices probing to determine the IOVA mode
> to be used, and adds a check right before the device is
> probed to ensure compatible IOVA mode has been selected.
> 
> It also adds a ABI exception rule to accommodate with an
> update on the driver registration API
> 
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> Signed-off-by: David Marchand <david.marchand@redhat.com>
> ---
>  devtools/libabigail.abignore    |  2 ++
>  drivers/bus/vdev/rte_bus_vdev.h |  4 ++++
>  drivers/bus/vdev/vdev.c         | 29 +++++++++++++++++++++++++++++
>  3 files changed, 35 insertions(+)
> 
> diff --git a/devtools/libabigail.abignore b/devtools/libabigail.abignore
> index 1dc84fa74b..170304c876 100644
> --- a/devtools/libabigail.abignore
> +++ b/devtools/libabigail.abignore
> @@ -11,6 +11,8 @@
>  ; Explicit ignore for driver-only ABI
>  [suppress_type]
>          name = eth_dev_ops
> +[suppress_function]
> +        name_regexp = rte_vdev_(|un)register
> 
>  ; Ignore fields inserted in cacheline boundary of rte_cryptodev
>  [suppress_type]
> diff --git a/drivers/bus/vdev/rte_bus_vdev.h b/drivers/bus/vdev/rte_bus_vdev.h
> index f99a41f825..fc315d10fa 100644
> --- a/drivers/bus/vdev/rte_bus_vdev.h
> +++ b/drivers/bus/vdev/rte_bus_vdev.h
> @@ -113,8 +113,12 @@ struct rte_vdev_driver {
>  	rte_vdev_remove_t *remove;       /**< Virtual device remove function. */
>  	rte_vdev_dma_map_t *dma_map;     /**< Virtual device DMA map function.
> */
>  	rte_vdev_dma_unmap_t *dma_unmap; /**< Virtual device DMA unmap function.
> */
> +	uint32_t drv_flags;              /**< Flags RTE_VDEV_DRV_*. */
>  };
> 
> +/** Device driver needs IOVA as VA and cannot work with IOVA as PA */
> +#define RTE_VDEV_DRV_NEED_IOVA_AS_VA 0x0001
> +
>  /**
>   * Register a virtual device driver.
>   *
> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c
> index acfd78828f..9a673347ae 100644
> --- a/drivers/bus/vdev/vdev.c
> +++ b/drivers/bus/vdev/vdev.c
> @@ -189,6 +189,7 @@ vdev_probe_all_drivers(struct rte_vdev_device *dev)
>  {
>  	const char *name;
>  	struct rte_vdev_driver *driver;
> +	enum rte_iova_mode iova_mode;
>  	int ret;
> 
>  	if (rte_dev_is_probed(&dev->device))
> @@ -199,6 +200,14 @@ vdev_probe_all_drivers(struct rte_vdev_device *dev)
> 
>  	if (vdev_parse(name, &driver))
>  		return -1;
> +
> +	iova_mode = rte_eal_iova_mode();
> +	if ((driver->drv_flags & RTE_VDEV_DRV_NEED_IOVA_AS_VA) && (iova_mode ==
> RTE_IOVA_PA)) {
> +		VDEV_LOG(ERR, "%s requires VA IOVA mode but current mode is PA,
> not initializing",
> +				name);
> +		return -1;
> +	}
> +
>  	ret = driver->probe(dev);
>  	if (ret == 0)
>  		dev->device.driver = &driver->driver;
> @@ -594,6 +603,25 @@ vdev_unplug(struct rte_device *dev)
>  	return rte_vdev_uninit(dev->name);
>  }
> 
> +static enum rte_iova_mode
> +vdev_get_iommu_class(void)
> +{
> +	const char *name;
> +	struct rte_vdev_device *dev;
> +	struct rte_vdev_driver *driver;
> +
> +	TAILQ_FOREACH(dev, &vdev_device_list, next) {
> +		name = rte_vdev_device_name(dev);
> +		if (vdev_parse(name, &driver))
> +			continue;
> +
> +		if (driver->drv_flags & RTE_VDEV_DRV_NEED_IOVA_AS_VA)
> +			return RTE_IOVA_VA;
> +	}
> +
> +	return RTE_IOVA_DC;
> +}
> +
>  static struct rte_bus rte_vdev_bus = {
>  	.scan = vdev_scan,
>  	.probe = vdev_probe,
> @@ -603,6 +631,7 @@ static struct rte_bus rte_vdev_bus = {
>  	.parse = vdev_parse,
>  	.dma_map = vdev_dma_map,
>  	.dma_unmap = vdev_dma_unmap,
> +	.get_iommu_class = vdev_get_iommu_class,
>  	.dev_iterate = rte_vdev_dev_iterate,
>  };
> 
> --
> 2.29.2

Reviewed-by: Chenbo Xia <chenbo.xia@intel.com>