arm/arm64: KVM: Take mmap_sem in kvm_arch_prepare_memory_region

arm/arm64: KVM: Take mmap_sem in kvm_arch_prepare_memory_region

commit 72f310481a08db821b614e7b5d00febcc9064b36 upstream.

We don't hold the mmap_sem while searching for VMAs (via find_vma), in
kvm_arch_prepare_memory_region, which can end up in expected failures.

Fixes: commit 8eef91239e57 ("arm/arm64: KVM: map MMIO regions at creation time")
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Auger <eric.auger@rehat.com>
Reviewed-by: Christoffer Dall <cdall@linaro.org>
[ Handle dirty page logging failure case ]
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>