KVM: arm64: Sort the hypervisor memblocks

We will soon need to check if a Physical Address belongs to a memblock
at EL2, so make sure to sort them so this can be done efficiently.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Quentin Perret <qperret@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210319100146.1149909-28-qperret@google.com

arch/arm64/kvm/hyp/reserved_mem.c

@@ -6,6 +6,7 @@
 
 #include <linux/kvm_host.h>
 #include <linux/memblock.h>
+#include <linux/sort.h>
 
 #include <asm/kvm_host.h>
 
@@ -18,6 +19,23 @@ static unsigned int *hyp_memblock_nr_ptr = &kvm_nvhe_sym(hyp_memblock_nr);
 phys_addr_t hyp_mem_base;
 phys_addr_t hyp_mem_size;
 
+static int cmp_hyp_memblock(const void *p1, const void *p2)
+{
+	const struct memblock_region *r1 = p1;
+	const struct memblock_region *r2 = p2;
+
+	return r1->base < r2->base ? -1 : (r1->base > r2->base);
+}
+
+static void __init sort_memblock_regions(void)
+{
+	sort(hyp_memory,
+	     *hyp_memblock_nr_ptr,
+	     sizeof(struct memblock_region),
+	     cmp_hyp_memblock,
+	     NULL);
+}
+
 static int __init register_memblock_regions(void)
 {
 	struct memblock_region *reg;
@@ -29,6 +47,7 @@ static int __init register_memblock_regions(void)
 		hyp_memory[*hyp_memblock_nr_ptr] = *reg;
 		(*hyp_memblock_nr_ptr)++;
 	}
+	sort_memblock_regions();
 
 	return 0;
 }