KVM: Define KVM_MEMSLOTS_NUM_MAX_DEFAULT

Make the default max nr_slots a macro, it's only used when KVM reports
nothing.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Link: https://lore.kernel.org/r/20240917163835.194664-3-peterx@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f84413b..c32a84e 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -71,6 +71,8 @@
 
 /* Default num of memslots to be allocated when VM starts */
 #define  KVM_MEMSLOTS_NR_ALLOC_DEFAULT                      16
+/* Default max allowed memslots if kernel reported nothing */
+#define  KVM_MEMSLOTS_NR_MAX_DEFAULT                        32
 
 struct KVMParkedVcpu {
     unsigned long vcpu_id;
@@ -2613,7 +2615,7 @@
 
     /* If unspecified, use the default value */
     if (!s->nr_slots) {
-        s->nr_slots = 32;
+        s->nr_slots_max = KVM_MEMSLOTS_NR_MAX_DEFAULT;
     }
 
     s->nr_as = kvm_check_extension(s, KVM_CAP_MULTI_ADDRESS_SPACE);