vfio/pci: Register a DMA fault response region

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I401IF


CVE: NA

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In preparation for vSVA, let's register a DMA fault response region,
where the userspace will push the page responses and increment the
head of the buffer. The kernel will pop those responses and inject them
on iommu side.

Signed-off-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Kunkun <Jiang&lt;jiangkunkun@huawei.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>