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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: shahafs@mellanox.com, lulu@redhat.com, saugatm@xilinx.com,
	mhabets@solarflare.com, vmireyno@marvell.com,
	linux-kernel@vger.kernel.org, gdawar@xilinx.com,
	virtualization@lists.linux-foundation.org, eperezma@redhat.com,
	hanand@xilinx.com, zhangweining@ruijie.com.cn, eli@mellanox.com,
	lingshan.zhu@intel.com, rob.miller@broadcom.com
Subject: Re: [PATCH 3/4] vdpa: get_iova_range() is mandatory for device specific DMA translation
Date: Wed, 5 Aug 2020 08:55:27 -0400	[thread overview]
Message-ID: <20200805085217-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200617032947.6371-4-jasowang@redhat.com>

On Wed, Jun 17, 2020 at 11:29:46AM +0800, Jason Wang wrote:
> In order to let userspace work correctly, get_iova_range() is a must
> for the device that has its own DMA translation logic.

I guess you mean for a device.

However in absence of ths op, I don't see what is wrong with just
assuming device can access any address.

> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/vdpa/vdpa.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index de211ef3738c..ab7af978ef70 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -82,6 +82,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
>  	if (!!config->dma_map != !!config->dma_unmap)
>  		goto err;
>  
> +	if ((config->dma_map || config->set_map) &&
> +	    !config->get_iova_range)
> +		goto err;
> +
>  	err = -ENOMEM;
>  	vdev = kzalloc(size, GFP_KERNEL);
>  	if (!vdev)

What about devices using an IOMMU for translation?
IOMMUs generally have a limited IOVA range too, right?



> -- 
> 2.20.1

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, rob.miller@broadcom.com,
	lingshan.zhu@intel.com, eperezma@redhat.com, lulu@redhat.com,
	shahafs@mellanox.com, hanand@xilinx.com, mhabets@solarflare.com,
	gdawar@xilinx.com, saugatm@xilinx.com, vmireyno@marvell.com,
	zhangweining@ruijie.com.cn, eli@mellanox.com
Subject: Re: [PATCH 3/4] vdpa: get_iova_range() is mandatory for device specific DMA translation
Date: Wed, 5 Aug 2020 08:55:27 -0400	[thread overview]
Message-ID: <20200805085217-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20200617032947.6371-4-jasowang@redhat.com>

On Wed, Jun 17, 2020 at 11:29:46AM +0800, Jason Wang wrote:
> In order to let userspace work correctly, get_iova_range() is a must
> for the device that has its own DMA translation logic.

I guess you mean for a device.

However in absence of ths op, I don't see what is wrong with just
assuming device can access any address.

> 
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/vdpa/vdpa.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
> index de211ef3738c..ab7af978ef70 100644
> --- a/drivers/vdpa/vdpa.c
> +++ b/drivers/vdpa/vdpa.c
> @@ -82,6 +82,10 @@ struct vdpa_device *__vdpa_alloc_device(struct device *parent,
>  	if (!!config->dma_map != !!config->dma_unmap)
>  		goto err;
>  
> +	if ((config->dma_map || config->set_map) &&
> +	    !config->get_iova_range)
> +		goto err;
> +
>  	err = -ENOMEM;
>  	vdev = kzalloc(size, GFP_KERNEL);
>  	if (!vdev)

What about devices using an IOMMU for translation?
IOMMUs generally have a limited IOVA range too, right?



> -- 
> 2.20.1


  reply	other threads:[~2020-08-05 12:55 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-17  3:29 [PATCH 0/4] vDPA: API for reporting IOVA range Jason Wang
2020-06-17  3:29 ` Jason Wang
2020-06-17  3:29 ` [PATCH 1/4] vdpa: introduce config op to get valid iova range Jason Wang
2020-06-17  3:29   ` Jason Wang
2020-08-05 12:51   ` Michael S. Tsirkin
2020-08-05 12:51     ` Michael S. Tsirkin
2020-08-06  3:25     ` Jason Wang
2020-08-06  3:25       ` Jason Wang
2020-08-06  5:54       ` Michael S. Tsirkin
2020-08-06  5:54         ` Michael S. Tsirkin
2020-08-06 12:03     ` Eli Cohen
2020-08-06 12:29       ` Michael S. Tsirkin
2020-08-06 12:29         ` Michael S. Tsirkin
2020-08-06 12:43         ` Eli Cohen
2020-08-10 12:05           ` Michael S. Tsirkin
2020-08-10 12:05             ` Michael S. Tsirkin
2020-08-11  2:53             ` Jason Wang
2020-08-11  2:53               ` Jason Wang
2020-08-11  8:29               ` Michael S. Tsirkin
2020-08-11  8:29                 ` Michael S. Tsirkin
2020-08-12  2:02                 ` Jason Wang
2020-08-12  2:02                   ` Jason Wang
2020-08-07  3:23         ` Jason Wang
2020-08-07  3:23           ` Jason Wang
2020-08-06 12:10   ` Eli Cohen
2020-08-07  3:04     ` Jason Wang
2020-08-07  3:04       ` Jason Wang
2020-06-17  3:29 ` [PATCH 2/4] vdpa_sim: implement get_iova_range bus operation Jason Wang
2020-06-17  3:29   ` Jason Wang
2020-06-17  3:29 ` [PATCH 3/4] vdpa: get_iova_range() is mandatory for device specific DMA translation Jason Wang
2020-06-17  3:29   ` Jason Wang
2020-08-05 12:55   ` Michael S. Tsirkin [this message]
2020-08-05 12:55     ` Michael S. Tsirkin
2020-08-06  3:27     ` Jason Wang
2020-08-06  3:27       ` Jason Wang
2020-06-17  3:29 ` [PATCH 4/4] vhost: vdpa: report iova range Jason Wang
2020-08-05 12:58   ` Michael S. Tsirkin
2020-08-05 12:58     ` Michael S. Tsirkin
2020-08-06  3:29     ` Jason Wang
2020-08-06  3:29       ` Jason Wang
2020-08-06  5:55       ` Michael S. Tsirkin
2020-08-06  5:55         ` Michael S. Tsirkin
2020-10-21 14:45 ` [PATCH 0/4] vDPA: API for reporting IOVA range Michael S. Tsirkin
2020-10-21 14:45   ` Michael S. Tsirkin
2020-10-22  5:47   ` Jason Wang
2020-10-22  5:47     ` Jason Wang

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