]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
KVM: arm64: Fix benign bug with incorrect use of VA_BITS
authorRyan Roberts <ryan.roberts@arm.com>
Mon, 5 Dec 2022 11:40:31 +0000 (11:40 +0000)
committerMarc Zyngier <maz@kernel.org>
Mon, 5 Dec 2022 14:17:53 +0000 (14:17 +0000)
commit219072c09abde0f1d0a6ce091be375e8eb7d08f0
tree9660c50fe597b51ea906c17146874e1937980bc3
parenta0d37784bfd7f699986ba3a64cfeb68a03cb7fd0
KVM: arm64: Fix benign bug with incorrect use of VA_BITS

get_user_mapping_size() uses kvm's pgtable library to walk a user space
page table created by the kernel, and in doing so, passes metadata
that the library needs, including ia_bits, which defines the size of the
input address.

For the case where the kernel is compiled for 52 VA bits but runs on HW
that does not support LVA, it will fall back to 48 VA bits at runtime.
Therefore we must use vabits_actual rather than VA_BITS to get the true
address size.

This is benign in the current code base because the pgtable library only
uses it for error checking.

Fixes: 6011cf68c885 ("KVM: arm64: Walk userspace page tables to compute the THP mapping size")
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221205114031.3972780-1-ryan.roberts@arm.com
arch/arm64/kvm/mmu.c