Re: [RFC PATCH 06/24] vhost-vdpa: switch to use vhost-vdpa specific IOTLB

From: Eli Cohen <elic@nvidia.com>
To: Jason Wang <jasowang@redhat.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>, <elic@nvidia.com>,
	<amorenoz@redhat.com>, <maxime.coquelin@redhat.com>,
	<stefanha@redhat.com>, <sgarzare@redhat.com>
Subject: Re: [RFC PATCH 06/24] vhost-vdpa: switch to use vhost-vdpa specific IOTLB
Date: Wed, 30 Sep 2020 15:02:02 +0300	[thread overview]
Message-ID: <20200930120202.GA229518@mtl-vdi-166.wap.labs.mlnx> (raw)
In-Reply-To: <20200924032125.18619-7-jasowang@redhat.com>

On Thu, Sep 24, 2020 at 11:21:07AM +0800, Jason Wang wrote:
> To ease the implementation of per group ASID support for vDPA
> device. This patch switches to use a vhost-vdpa specific IOTLB to
> avoid the unnecessary refactoring of the vhost core.
> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/vhost/vdpa.c | 14 ++++++++------
>  1 file changed, 8 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 74bef1c15a70..ec3c94f706c1 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -40,6 +40,7 @@ struct vhost_vdpa {
>  	struct vhost_virtqueue *vqs;
>  	struct completion completion;
>  	struct vdpa_device *vdpa;
> +	struct vhost_iotlb *iotlb;
>  	struct device dev;
>  	struct cdev cdev;
>  	atomic_t opened;
> @@ -514,12 +515,11 @@ static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v,
>  
>  static void vhost_vdpa_iotlb_free(struct vhost_vdpa *v)
>  {
> -	struct vhost_dev *dev = &v->vdev;
> -	struct vhost_iotlb *iotlb = dev->iotlb;
> +	struct vhost_iotlb *iotlb = v->iotlb;
>  
>  	vhost_vdpa_iotlb_unmap(v, iotlb, 0ULL, 0ULL - 1);
> -	kfree(dev->iotlb);
> -	dev->iotlb = NULL;
> +	kfree(v->iotlb);
> +	v->iotlb = NULL;
>  }
>  
>  static int perm_to_iommu_flags(u32 perm)
> @@ -681,7 +681,7 @@ static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
>  	struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
>  	struct vdpa_device *vdpa = v->vdpa;
>  	const struct vdpa_config_ops *ops = vdpa->config;
> -	struct vhost_iotlb *iotlb = dev->iotlb;
> +	struct vhost_iotlb *iotlb = v->iotlb;
>  	int r = 0;
>  
>  	r = vhost_dev_check_owner(dev);
> @@ -812,12 +812,14 @@ static int vhost_vdpa_open(struct inode *inode, struct file *filep)
>  
>  	r = vhost_vdpa_alloc_domain(v);
>  	if (r)
> -		goto err_init_iotlb;
> +		goto err_alloc_domain;

You're still using this:
dev->iotlb = vhost_iotlb_alloc(0, 0);

Shouldn't you use
v->iotlb = host_iotlb_alloc(0, 0);

to set the vdpa device iotlb field?

>  
>  	filep->private_data = v;
>  
>  	return 0;
>  
> +err_alloc_domain:
> +	vhost_vdpa_iotlb_free(v);
>  err_init_iotlb:
>  	vhost_vdpa_cleanup(v);
>  err:
> -- 
> 2.20.1
> 