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Subject: Re: [PATCH v7 2/6] vfio/type1: Check reserve region conflict and
 update iova list
To:     Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
        alex.williamson@redhat.com, pmorel@linux.vnet.ibm.com
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        iommu@lists.linux-foundation.org, linuxarm@huawei.com,
        john.garry@huawei.com, xuwei5@hisilicon.com, kevin.tian@intel.com
References: <20190626151248.11776-1-shameerali.kolothum.thodi@huawei.com>
 <20190626151248.11776-3-shameerali.kolothum.thodi@huawei.com>
From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <3f190415-3ed0-247a-e761-7fd8c160dded@redhat.com>
Date:   Sun, 7 Jul 2019 17:02:56 +0200
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Hi Shameer,

On 6/26/19 5:12 PM, Shameer Kolothum wrote:
> This retrieves the reserved regions associated with dev group and
> checks for conflicts with any existing dma mappings. Also update
> the iova list excluding the reserved regions.

s/reserve/reserved in the commit title
> 
> Reserved regions with type IOMMU_RESV_DIRECT_RELAXABLE are
> excluded from above checks as they are considered as directly
> mapped regions which are known to be relaxable.
> 
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> ---
>  drivers/vfio/vfio_iommu_type1.c | 96 +++++++++++++++++++++++++++++++++
>  1 file changed, 96 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 970d1ec06aed..b6bfdfa16c33 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -1508,6 +1508,88 @@ static int vfio_iommu_aper_resize(struct list_head *iova,
>  	return 0;
>  }
>  
> +/*
> + * Check reserved region conflicts with existing dma mappings
> + */
> +static bool vfio_iommu_resv_conflict(struct vfio_iommu *iommu,
> +				     struct list_head *resv_regions)
> +{
> +	struct iommu_resv_region *region;
> +
> +	/* Check for conflict with existing dma mappings */
> +	list_for_each_entry(region, resv_regions, list) {
> +		if (region->type == IOMMU_RESV_DIRECT_RELAXABLE)
> +			continue;
> +
> +		if (vfio_find_dma(iommu, region->start, region->length))
> +			return true;
> +	}
> +
> +	return false;
> +}
> +
> +/*
> + * Check iova region overlap with  reserved regions and
> + * exclude them from the iommu iova range
> + */
> +static int vfio_iommu_resv_exclude(struct list_head *iova,
> +				   struct list_head *resv_regions)
> +{
> +	struct iommu_resv_region *resv;
> +	struct vfio_iova *n, *next;
> +
> +	list_for_each_entry(resv, resv_regions, list) {
> +		phys_addr_t start, end;
> +
> +		if (resv->type == IOMMU_RESV_DIRECT_RELAXABLE)
> +			continue;
> +
> +		start = resv->start;
> +		end = resv->start + resv->length - 1;
> +
> +		list_for_each_entry_safe(n, next, iova, list) {
> +			int ret = 0;
> +
> +			/* No overlap */
> +			if (start > n->end || end < n->start)
> +				continue;
> +			/*
> +			 * Insert a new node if current node overlaps with the
> +			 * reserve region to exlude that from valid iova range.
> +			 * Note that, new node is inserted before the current
> +			 * node and finally the current node is deleted keeping
> +			 * the list updated and sorted.
> +			 */
> +			if (start > n->start)
> +				ret = vfio_iommu_iova_insert(&n->list, n->start,
> +							     start - 1);
> +			if (!ret && end < n->end)
> +				ret = vfio_iommu_iova_insert(&n->list, end + 1,
> +							     n->end);
> +			if (ret)
> +				return ret;
> +
> +			list_del(&n->list);
> +			kfree(n);
> +		}
> +	}
> +
> +	if (list_empty(iova))
> +		return -EINVAL;
> +
> +	return 0;
> +}
> +
> +static void vfio_iommu_resv_free(struct list_head *resv_regions)
> +{
> +	struct iommu_resv_region *n, *next;
> +
> +	list_for_each_entry_safe(n, next, resv_regions, list) {
> +		list_del(&n->list);
> +		kfree(n);
> +	}
> +}
> +
>  static void vfio_iommu_iova_free(struct list_head *iova)
>  {
>  	struct vfio_iova *n, *next;
> @@ -1559,6 +1641,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  	phys_addr_t resv_msi_base;
>  	struct iommu_domain_geometry geo;
>  	LIST_HEAD(iova_copy);
> +	LIST_HEAD(group_resv_regions);
>  
>  	mutex_lock(&iommu->lock);
>  
> @@ -1644,6 +1727,13 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  		goto out_detach;
>  	}
>  
> +	iommu_get_group_resv_regions(iommu_group, &group_resv_regions);
> +
> +	if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) {
> +		ret = -EINVAL;
> +		goto out_detach;
> +	}
> +
>  	/* Get a copy of the current iova list and work on it */
>  	ret = vfio_iommu_iova_get_copy(iommu, &iova_copy);
>  	if (ret)
> @@ -1654,6 +1744,10 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  	if (ret)
>  		goto out_detach;
>  
> +	ret = vfio_iommu_resv_exclude(&iova_copy, &group_resv_regions);
> +	if (ret)
> +		goto out_detach;
> +
>  	resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base);
>  
>  	INIT_LIST_HEAD(&domain->group_list);
> @@ -1714,6 +1808,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  	/* Delete the old one and insert new iova list */
>  	vfio_iommu_iova_insert_copy(iommu, &iova_copy);
>  	mutex_unlock(&iommu->lock);
> +	vfio_iommu_resv_free(&group_resv_regions);
>  
>  	return 0;
>  
> @@ -1722,6 +1817,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
>  out_domain:
>  	iommu_domain_free(domain->domain);
>  	vfio_iommu_iova_free(&iova_copy);
> +	vfio_iommu_resv_free(&group_resv_regions);
>  out_free:
>  	kfree(domain);
>  	kfree(group);
> 
Thanks

Eric