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From: Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Subject: Re: [PATCH v2 13/40] vfio: Add support for Shared Virtual Addressing
To: Xu Zaibo <xuzaibo@huawei.com>,
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 <5B0536A3.1000304@huawei.com>
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Date: Thu, 24 May 2018 12:44:47 +0100
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Hi,

On 23/05/18 10:38, Xu Zaibo wrote:
>> +static int vfio_iommu_bind_group(struct vfio_iommu *iommu,
>> +                 struct vfio_group *group,
>> +                 struct vfio_mm *vfio_mm)
>> +{
>> +    int ret;
>> +    bool enabled_sva = false;
>> +    struct vfio_iommu_sva_bind_data data = {
>> +        .vfio_mm    = vfio_mm,
>> +        .iommu        = iommu,
>> +        .count        = 0,
>> +    };
>> +
>> +    if (!group->sva_enabled) {
>> +        ret = iommu_group_for_each_dev(group->iommu_group, NULL,
>> +                           vfio_iommu_sva_init);
> Do we need to do *sva_init here or do anything to avoid repeated
> initiation?
> while another process already did initiation at this device, I think
> that current process will get an EEXIST.

Right, sva_init() must be called once for any device that intends to use
bind(). For the second process though, group->sva_enabled will be true
so we won't call sva_init() again, only bind().

Thanks,
Jean