powerpc: Fix reverse map real-mode address lookup with huge vmalloc

mainline inclusion
from mainline-5.13-rc5
commit 5362a4b6
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I3ZGKZ


CVE: NA

-------------------------------------------------

real_vmalloc_addr() does not currently work for huge vmalloc, which is
what the reverse map can be allocated with for radix host, hash guest.

Extract the hugepage aware equivalent from eeh code into a helper, and
convert existing sites including this one to use it.

Fixes: 8abddd96 ("powerpc/64s/radix: Enable huge vmalloc mappings")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210526120005.3432222-1-npiggin@gmail.com


Signed-off-by: Chen Wandun <chenwandun@huawei.com>
Reviewed-by: Tong Tiangen <tongtiangen@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>