FROMGIT: KVM: arm64: Fix range alignment when walking page tables

When walking the page tables at a given level, and if the start
address for the range isn't aligned for that level, we propagate
the misalignment on each iteration at that level.

This results in the walker ignoring a number of entries (depending
on the original misalignment) on each subsequent iteration.

Properly aligning the address before the next iteration addresses
this issue.

Cc: stable@vger.kernel.org
Reported-by: Howard Zhang <Howard.Zhang@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Jia He <justin.he@arm.com>
Fixes: b1e57de6 ("KVM: arm64: Add stand-alone page-table walker infrastructure")
[maz: rewrite commit message]
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210303024225.2591-1-justin.he@arm.com
(cherry picked from commit e85583b3f1fe62c9b371a3100c1c91af94005ca9
 git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git

 fixes)
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 178098380
Test: atest VirtualizationHostTestCases on an EL2-enabled device
Change-Id: Ic5d8a5966201610ead899eacf1d75b94df572be8