linux-kernel - Re: [PATCH v7 4/6] vfio/type1: check dma map request is within a valid iova range

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Date:   Sun, 7 Jul 2019 17:03:28 +0200
From:   Auger Eric <eric.auger@...hat.com>
To:     Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>,
        alex.williamson@...hat.com, pmorel@...ux.vnet.ibm.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        iommu@...ts.linux-foundation.org, linuxarm@...wei.com,
        john.garry@...wei.com, xuwei5@...ilicon.com, kevin.tian@...el.com
Subject: Re: [PATCH v7 4/6] vfio/type1: check dma map request is within a
 valid iova range

Hi Shameer,

On 6/26/19 5:12 PM, Shameer Kolothum wrote:
> This checks and rejects any dma map request outside valid iova
> range.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@...wei.com>
> ---
> v6 --> v7
> 
> Addressed the case where a container with only an mdev device will
> have an empty list(Suggested by Alex).
> ---
>  drivers/vfio/vfio_iommu_type1.c | 26 ++++++++++++++++++++++++++
>  1 file changed, 26 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index e872fb3a0f39..89ad0da7152c 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -1050,6 +1050,27 @@ static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
>  	return ret;
>  }
>  
> +/*
> + * Check dma map request is within a valid iova range
> + */
> +static bool vfio_iommu_iova_dma_valid(struct vfio_iommu *iommu,
> +				      dma_addr_t start, dma_addr_t end)
> +{
> +	struct list_head *iova = &iommu->iova_list;
> +	struct vfio_iova *node;
> +
> +	list_for_each_entry(node, iova, list) {
> +		if (start >= node->start && end <= node->end)
> +			return true;
> +	}
> +
> +	/*
> +	 * Check for list_empty() as well since a container with
> +	 * only an mdev device will have an empty list.
> +	 */
> +	return list_empty(&iommu->iova_list);
iova

Besides
Reviewed-by: Eric Auger <eric.auger@...hat.com>

Thanks

Eric


> +}
> +
>  static int vfio_dma_do_map(struct vfio_iommu *iommu,
>  			   struct vfio_iommu_type1_dma_map *map)
>  {
> @@ -1093,6 +1114,11 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
>  		goto out_unlock;
>  	}
>  
> +	if (!vfio_iommu_iova_dma_valid(iommu, iova, iova + size - 1)) {
> +		ret = -EINVAL;
> +		goto out_unlock;
> +	}
> +
>  	dma = kzalloc(sizeof(*dma), GFP_KERNEL);
>  	if (!dma) {
>  		ret = -ENOMEM;
>