linux-kernel - Re: [RFC v2 3/5] vfio/type1: check dma map request is within a valid iova range

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Message-ID: <90924c96-2170-04ba-c40e-cdb93ca559d0@redhat.com>
Date:   Tue, 23 Jan 2018 09:38:27 +0100
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,
        linuxarm@...wei.com, john.garry@...wei.com, xuwei5@...ilicon.com
Subject: Re: [RFC v2 3/5] vfio/type1: check dma map request is within a valid
 iova range

Hi Shameer,

On 12/01/18 17:45, 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>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 22 ++++++++++++++++++++++
>  1 file changed, 22 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 7609070..47ea490 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -971,6 +971,23 @@ 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,
> +				phys_addr_t start, phys_addr_t end)
s/phys_addr_t/dma_addr_t here also.
> +{
> +	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;
> +	}
> +
> +	return false;
> +}
> +
>  static int vfio_dma_do_map(struct vfio_iommu *iommu,
>  			   struct vfio_iommu_type1_dma_map *map)
>  {
> @@ -1009,6 +1026,11 @@ 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;
> 

Thanks

Eric