Re: [dpdk-dev] [PATCH v3 02/44] bus/vdev: add driver IOVA VA mode requirement

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 1/26/21 10:23 AM, Xia, Chenbo wrote:
> Hi Maxime,
> 
>> -----Original Message-----
>> From: Maxime Coquelin <maxime.coquelin@redhat.com>
>> Sent: Tuesday, January 26, 2021 1:14 AM
>> 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 v3 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.
>>
>> It also adds a check right before the device is probed to
>> ensure compatible IOVa mode has been selected.
> 
> s/IOVa/IOVA

Just spotted it while reworking the commit message :)

>>
>> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
>> ---
>>  drivers/bus/vdev/rte_bus_vdev.h |  4 ++++
>>  drivers/bus/vdev/vdev.c         | 29 +++++++++++++++++++++++++++++
>>  2 files changed, 33 insertions(+)
>>
>> diff --git a/drivers/bus/vdev/rte_bus_vdev.h b/drivers/bus/vdev/rte_bus_vdev.h
>> index f99a41f825..c8b41e649c 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_*. */
> 
> I remember David mentioned that the comment above should be consistent with others, which
> also makes sense to me
> 
> Thanks,
> Chenbo
> 
>>  };
>>
>> +/** 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
>