KVM: arm64: Minor optimization of range_is_memory

Currently range_is_memory finds the corresponding struct memblock_region
for both the lower and upper bounds of the given address range with two
rounds of binary search, and then checks that the two memblocks are the
same. Simplify this by only doing binary search on the lower bound and
then checking that the upper bound is in the same memblock.
Signed-off-by: David Brazdil <dbrazdil@google.com>
Reviewed-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210728153232.1018911-3-dbrazdil@google.com

arch/arm64/kvm/hyp/nvhe/mem_protect.c

@@ -204,16 +204,19 @@ bool addr_is_memory(phys_addr_t phys)
 	return find_mem_range(phys, &range);
 }
 
+static bool is_in_mem_range(u64 addr, struct kvm_mem_range *range)
+{
+	return range->start <= addr && addr < range->end;
+}
+
 static bool range_is_memory(u64 start, u64 end)
 {
-	struct kvm_mem_range r1, r2;
+	struct kvm_mem_range r;
 
-	if (!find_mem_range(start, &r1) || !find_mem_range(end - 1, &r2))
-		return false;
-	if (r1.start != r2.start)
+	if (!find_mem_range(start, &r))
 		return false;
 
-	return true;
+	return is_in_mem_range(end - 1, &r);
 }
 
 static inline int __host_stage2_idmap(u64 start, u64 end,