iommu/io-pgtable-arm: Add and realize split_block ops

virt inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I3ZUKK


CVE: NA

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Block(largepage) mapping is not a proper granule for dirty log tracking.
Take an extreme example, if DMA writes one byte, under 1G mapping, the
dirty amount reported is 1G, but under 4K mapping, the dirty amount is
just 4K.

This splits block descriptor to an span of page descriptors. BBML1 or
BBML2 feature is required.

Spliting block is designed to be only used by dirty log tracking, which
does not concurrently work with other pgtable ops that access underlying
page table, so race condition does not exist.

Co-developed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Kunkun Jiang <jiangkunkun@huawei.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>