KVM: arm64: Make nVHE ASLR conditional on RANDOMIZE_BASE

If there are spare bits in non-VHE hyp VA, KVM unconditionally replaces them
with a random tag chosen at init. Disable this if the kernel is built without
RANDOMIZE_BASE to align with kernel behavior.

Signed-off-by: David Brazdil <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: David Brazdil

arch/arm64/kvm/va_layout.c

@@ -48,7 +48,7 @@ __init void kvm_compute_layout(void)
 	va_mask = GENMASK_ULL(tag_lsb - 1, 0);
 	tag_val = hyp_va_msb;
 
-	if (tag_lsb != (vabits_actual - 1)) {
+	if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && tag_lsb != (vabits_actual - 1)) {
 		/* We have some free bits to insert a random tag. */
 		tag_val |= get_random_long() & GENMASK_ULL(vabits_actual - 2, tag_lsb);
 	}