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Subject: Re: [RFC PATCH 09/24] vdpa: multiple address spaces support
To:     Eli Cohen <elic@nvidia.com>
Cc:     mst@redhat.com, lulu@redhat.com, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, rob.miller@broadcom.com,
        lingshan.zhu@intel.com, eperezma@redhat.com, hanand@xilinx.com,
        mhabets@solarflare.com, amorenoz@redhat.com,
        maxime.coquelin@redhat.com, stefanha@redhat.com,
        sgarzare@redhat.com
References: <20200924032125.18619-1-jasowang@redhat.com>
 <20200924032125.18619-10-jasowang@redhat.com>
 <20201001132124.GA32363@mtl-vdi-166.wap.labs.mlnx>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <028ebad8-2106-0ea9-4092-4c14f1e2fdfe@redhat.com>
Date:   Fri, 9 Oct 2020 11:51:44 +0800
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On 2020/10/1 下午9:21, Eli Cohen wrote:
> On Thu, Sep 24, 2020 at 11:21:10AM +0800, Jason Wang wrote:
>> This patches introduces the multiple address spaces support for vDPA
>> device. This idea is to identify a specific address space via an
>> dedicated identifier - ASID.
>>
>> During vDPA device allocation, vDPA device driver needs to report the
>> number of address spaces supported by the device then the DMA mapping
>> ops of the vDPA device needs to be extended to support ASID.
>>
>> This helps to isolate the DMA among the virtqueues. E.g in the case of
>> virtio-net, the control virtqueue will not be assigned directly to
>> guest.
>>
>> This RFC patch only converts for the device that wants its own
>> IOMMU/DMA translation logic. So it will rejects the device with more
>> that 1 address space that depends on platform IOMMU. The plan to
> This is not apparent from the code. Instead you enforce number of groups
> to 1.


Yes, will fix.


>
>> moving all the DMA mapping logic to the vDPA device driver instead of
>> doing it in vhost-vDPA (otherwise it could result a very complicated
>> APIs and actually vhost-vDPA doesn't care about how the actual
>> composition/emulation were done in the device driver).
>>
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>   drivers/vdpa/ifcvf/ifcvf_main.c   |  2 +-
>>   drivers/vdpa/mlx5/net/mlx5_vnet.c |  5 +++--
>>   drivers/vdpa/vdpa.c               |  4 +++-
>>   drivers/vdpa/vdpa_sim/vdpa_sim.c  | 10 ++++++----
>>   drivers/vhost/vdpa.c              | 14 +++++++++-----
>>   include/linux/vdpa.h              | 23 ++++++++++++++++-------
>>   6 files changed, 38 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/vdpa/ifcvf/ifcvf_main.c b/drivers/vdpa/ifcvf/ifcvf_main.c
>> index e6a0be374e51..86cdf5f8bcae 100644
>> --- a/drivers/vdpa/ifcvf/ifcvf_main.c
>> +++ b/drivers/vdpa/ifcvf/ifcvf_main.c
>> @@ -440,7 +440,7 @@ static int ifcvf_probe(struct pci_dev *pdev, const struct pci_device_id *id)
>>   
>>   	adapter = vdpa_alloc_device(struct ifcvf_adapter, vdpa,
>>   				    dev, &ifc_vdpa_ops,
>> -				    IFCVF_MAX_QUEUE_PAIRS * 2, 1);
>> +				    IFCVF_MAX_QUEUE_PAIRS * 2, 1, 1);
>>   
>>   	if (adapter == NULL) {
>>   		IFCVF_ERR(pdev, "Failed to allocate vDPA structure");
>> diff --git a/drivers/vdpa/mlx5/net/mlx5_vnet.c b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> index 4e480f4f754e..db7404e121bf 100644
>> --- a/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> +++ b/drivers/vdpa/mlx5/net/mlx5_vnet.c
>> @@ -1788,7 +1788,8 @@ static u32 mlx5_vdpa_get_generation(struct vdpa_device *vdev)
>>   	return mvdev->generation;
>>   }
>>   
>> -static int mlx5_vdpa_set_map(struct vdpa_device *vdev, struct vhost_iotlb *iotlb)
>> +static int mlx5_vdpa_set_map(struct vdpa_device *vdev, unsigned int asid,
>> +			     struct vhost_iotlb *iotlb)
>>   {
>>   	struct mlx5_vdpa_dev *mvdev = to_mvdev(vdev);
>>   	struct mlx5_vdpa_net *ndev = to_mlx5_vdpa_ndev(mvdev);
>> @@ -1931,7 +1932,7 @@ void *mlx5_vdpa_add_dev(struct mlx5_core_dev *mdev)
>>   	max_vqs = min_t(u32, max_vqs, MLX5_MAX_SUPPORTED_VQS);
>>   
>>   	ndev = vdpa_alloc_device(struct mlx5_vdpa_net, mvdev.vdev, mdev->device, &mlx5_vdpa_ops,
>> -				 2 * mlx5_vdpa_max_qps(max_vqs), 1);
>> +				 2 * mlx5_vdpa_max_qps(max_vqs), 1, 1);
>>   	if (IS_ERR(ndev))
>>   		return ndev;
>>   
>> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
>> index 46399746ec7c..05195fa7865d 100644
>> --- a/drivers/vdpa/vdpa.c
>> +++ b/drivers/vdpa/vdpa.c
>> @@ -63,6 +63,7 @@ static void vdpa_release_dev(struct device *d)
>>    * @config: the bus operations that is supported by this device
>>    * @nvqs: number of virtqueues supported by this device
>>    * @ngroups: number of groups supported by this device
>> + * @nas: number of address spaces supported by this device
>>    * @size: size of the parent structure that contains private data
>>    *
>>    * Driver should use vdpa_alloc_device() wrapper macro instead of
>> @@ -74,7 +75,7 @@ static void vdpa_release_dev(struct device *d)
>>   struct vdpa_device *__vdpa_alloc_device(struct device *parent,
>>   					const struct vdpa_config_ops *config,
>>   					int nvqs, unsigned int ngroups,
>> -					size_t size)
>> +					unsigned int nas, size_t size)
>>   {
>>   	struct vdpa_device *vdev;
>>   	int err = -EINVAL;
>> @@ -102,6 +103,7 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
>>   	vdev->features_valid = false;
>>   	vdev->nvqs = nvqs;
>>   	vdev->ngroups = ngroups;
>> +	vdev->nas = nas;
>>   
>>   	err = dev_set_name(&vdev->dev, "vdpa%u", vdev->index);
>>   	if (err)
>> diff --git a/drivers/vdpa/vdpa_sim/vdpa_sim.c b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> index 6669c561bc6e..5dc04ec271bb 100644
>> --- a/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> +++ b/drivers/vdpa/vdpa_sim/vdpa_sim.c
>> @@ -354,7 +354,7 @@ static struct vdpasim *vdpasim_create(void)
>>   		ops = &vdpasim_net_config_ops;
>>   
>>   	vdpasim = vdpa_alloc_device(struct vdpasim, vdpa, NULL, ops,
>> -				    VDPASIM_VQ_NUM, 1);
>> +				    VDPASIM_VQ_NUM, 1, 1);
>>   	if (!vdpasim)
>>   		goto err_alloc;
>>   
>> @@ -581,7 +581,7 @@ static u32 vdpasim_get_generation(struct vdpa_device *vdpa)
>>   	return vdpasim->generation;
>>   }
>>   
>> -static int vdpasim_set_map(struct vdpa_device *vdpa,
>> +static int vdpasim_set_map(struct vdpa_device *vdpa, unsigned int asid,
>>   			   struct vhost_iotlb *iotlb)
>>   {
>>   	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>> @@ -608,7 +608,8 @@ static int vdpasim_set_map(struct vdpa_device *vdpa,
>>   	return ret;
>>   }
>>   
>> -static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size,
>> +static int vdpasim_dma_map(struct vdpa_device *vdpa, unsigned int asid,
>> +			   u64 iova, u64 size,
>>   			   u64 pa, u32 perm)
>>   {
>>   	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>> @@ -622,7 +623,8 @@ static int vdpasim_dma_map(struct vdpa_device *vdpa, u64 iova, u64 size,
>>   	return ret;
>>   }
>>   
>> -static int vdpasim_dma_unmap(struct vdpa_device *vdpa, u64 iova, u64 size)
>> +static int vdpasim_dma_unmap(struct vdpa_device *vdpa, unsigned int asid,
>> +			     u64 iova, u64 size)
>>   {
>>   	struct vdpasim *vdpasim = vdpa_to_sim(vdpa);
>>   
>> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
>> index ec3c94f706c1..eeefcd971e3f 100644
>> --- a/drivers/vhost/vdpa.c
>> +++ b/drivers/vhost/vdpa.c
>> @@ -557,10 +557,10 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, struct vhost_iotlb *iotlb,
>>   		return r;
>>   
>>   	if (ops->dma_map) {
>> -		r = ops->dma_map(vdpa, iova, size, pa, perm);
>> +		r = ops->dma_map(vdpa, 0, iova, size, pa, perm);
>>   	} else if (ops->set_map) {
>>   		if (!v->in_batch)
>> -			r = ops->set_map(vdpa, iotlb);
>> +			r = ops->set_map(vdpa, 0, iotlb);
>>   	} else {
>>   		r = iommu_map(v->domain, iova, pa, size,
>>   			      perm_to_iommu_flags(perm));
>> @@ -579,10 +579,10 @@ static void vhost_vdpa_unmap(struct vhost_vdpa *v,
>>   	vhost_vdpa_iotlb_unmap(v, iotlb, iova, iova + size - 1);
>>   
>>   	if (ops->dma_map) {
>> -		ops->dma_unmap(vdpa, iova, size);
>> +		ops->dma_unmap(vdpa, 0, iova, size);
>>   	} else if (ops->set_map) {
>>   		if (!v->in_batch)
>> -			ops->set_map(vdpa, iotlb);
>> +			ops->set_map(vdpa, 0, iotlb);
>>   	} else {
>>   		iommu_unmap(v->domain, iova, size);
>>   	}
>> @@ -700,7 +700,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
>>   		break;
>>   	case VHOST_IOTLB_BATCH_END:
>>   		if (v->in_batch && ops->set_map)
>> -			ops->set_map(vdpa, iotlb);
>> +			ops->set_map(vdpa, 0, iotlb);
>>   		v->in_batch = false;
>>   		break;
>>   	default:
>> @@ -949,6 +949,10 @@ static int vhost_vdpa_probe(struct vdpa_device *vdpa)
>>   	int minor;
>>   	int r;
>>   
>> +	/* Only support 1 address space */
>> +	if (vdpa->ngroups != 1)
>> +		return -ENOTSUPP;
>> +
> Did you mean to check agains vdpa->nas?


I think we should check both.

Thanks


>
>>   	/* Currently, we only accept the network devices. */
>>   	if (ops->get_device_id(vdpa) != VIRTIO_ID_NET)
>>   		return -ENOTSUPP;
>> diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
>> index d829512efd27..1e1163daa352 100644
>> --- a/include/linux/vdpa.h
>> +++ b/include/linux/vdpa.h
>> @@ -43,6 +43,8 @@ struct vdpa_vq_state {
>>    * @index: device index
>>    * @features_valid: were features initialized? for legacy guests
>>    * @nvqs: the number of virtqueues
>> + * @ngroups: the number of virtqueue groups
>> + * @nas: the number of address spaces
>>    */
>>   struct vdpa_device {
>>   	struct device dev;
>> @@ -52,6 +54,7 @@ struct vdpa_device {
>>   	bool features_valid;
>>   	int nvqs;
>>   	unsigned int ngroups;
>> +	unsigned int nas;
>>   };
>>   
>>   /**
>> @@ -161,6 +164,7 @@ struct vdpa_device {
>>    *				Needed for device that using device
>>    *				specific DMA translation (on-chip IOMMU)
>>    *				@vdev: vdpa device
>> + *				@asid: address space identifier
>>    *				@iotlb: vhost memory mapping to be
>>    *				used by the vDPA
>>    *				Returns integer: success (0) or error (< 0)
>> @@ -169,6 +173,7 @@ struct vdpa_device {
>>    *				specific DMA translation (on-chip IOMMU)
>>    *				and preferring incremental map.
>>    *				@vdev: vdpa device
>> + *				@asid: address space identifier
>>    *				@iova: iova to be mapped
>>    *				@size: size of the area
>>    *				@pa: physical address for the map
>> @@ -180,6 +185,7 @@ struct vdpa_device {
>>    *				specific DMA translation (on-chip IOMMU)
>>    *				and preferring incremental unmap.
>>    *				@vdev: vdpa device
>> + *				@asid: address space identifier
>>    *				@iova: iova to be unmapped
>>    *				@size: size of the area
>>    *				Returns integer: success (0) or error (< 0)
>> @@ -225,10 +231,12 @@ struct vdpa_config_ops {
>>   	u32 (*get_generation)(struct vdpa_device *vdev);
>>   
>>   	/* DMA ops */
>> -	int (*set_map)(struct vdpa_device *vdev, struct vhost_iotlb *iotlb);
>> -	int (*dma_map)(struct vdpa_device *vdev, u64 iova, u64 size,
>> -		       u64 pa, u32 perm);
>> -	int (*dma_unmap)(struct vdpa_device *vdev, u64 iova, u64 size);
>> +	int (*set_map)(struct vdpa_device *vdev, unsigned int asid,
>> +		       struct vhost_iotlb *iotlb);
>> +	int (*dma_map)(struct vdpa_device *vdev, unsigned int asid,
>> +		       u64 iova, u64 size, u64 pa, u32 perm);
>> +	int (*dma_unmap)(struct vdpa_device *vdev, unsigned int asid,
>> +			 u64 iova, u64 size);
>>   
>>   	/* Free device resources */
>>   	void (*free)(struct vdpa_device *vdev);
>> @@ -237,11 +245,12 @@ struct vdpa_config_ops {
>>   struct vdpa_device *__vdpa_alloc_device(struct device *parent,
>>   					const struct vdpa_config_ops *config,
>>   					int nvqs, unsigned int ngroups,
>> -					size_t size);
>> +					unsigned int nas, size_t size);
>>   
>> -#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, ngroups) \
>> +#define vdpa_alloc_device(dev_struct, member, parent, config, nvqs, \
>> +			  ngroups, nas)				    \
>>   			  container_of(__vdpa_alloc_device( \
>> -				       parent, config, nvqs, ngroups, \
>> +				       parent, config, nvqs, ngroups, nas,  \
>>   				       sizeof(dev_struct) + \
>>   				       BUILD_BUG_ON_ZERO(offsetof( \
>>   				       dev_struct, member))), \
>> -- 
>> 2.20.1
>>