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Subject: Re: [PATCH V2 2/3] vhost: vdpa: report iova range
To:     Eli Cohen <elic@nvidia.com>
Cc:     mst@redhat.com, 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
References: <20200821092813.8952-1-jasowang@redhat.com>
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 <20200823064035.GB147797@mtl-vdi-166.wap.labs.mlnx>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <96f2367e-8b9f-9ee7-a45e-56e9162e92c6@redhat.com>
Date:   Mon, 31 Aug 2020 16:38:40 +0800
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On 2020/8/23 下午2:40, Eli Cohen wrote:
>> +static void vhost_vdpa_set_iova_range(struct vhost_vdpa *v)
>> +{
>> +	struct vdpa_iova_range *range = &v->range;
>> +	struct iommu_domain_geometry geo;
>> +	struct vdpa_device *vdpa = v->vdpa;
>> +	const struct vdpa_config_ops *ops = vdpa->config;
>> +
>> +	if (ops->get_iova_range) {
>> +		*range = ops->get_iova_range(vdpa);
>> +	} else if (v->domain &&
>> +		   !iommu_domain_get_attr(v->domain,
>> +		   DOMAIN_ATTR_GEOMETRY, &geo) &&
>> +		   geo.force_aperture) {
>> +		range->first = geo.aperture_start;
>> +		range->last = geo.aperture_end;
>> +	} else {
>> +		range->first = 0;
>> +		range->last = ULLONG_MAX;
>> +	}
> Shouldn't we require drivers that publish VIRTIO_F_ACCESS_PLATFORM to
> implement get_iova_range?


Probably not, since ACCESS_PLATFORM does not exclude the device that 
depends on the chipset IOMMU to work. So in that case, we should query 
IOMMU driver instead of vDPA device driver.

Thanks


>
>> +}