diff --git a/xen/arch/x86/cpu/microcode/core.c b/xen/arch/x86/cpu/microcode/core.c
index 5b42aad2fdd0..f7ce2247a33e 100644
--- a/xen/arch/x86/cpu/microcode/core.c
+++ b/xen/arch/x86/cpu/microcode/core.c
@@ -152,8 +152,7 @@ static int __init cf_check parse_ucode(const char *s)
 }
 custom_param("ucode", parse_ucode);
 
-static void __init microcode_scan_module(
-    unsigned long *module_map, const struct boot_info *bi)
+static void __init microcode_scan_module(const struct boot_info *bi)
 {
     uint64_t *_blob_start;
     unsigned long _blob_size;
@@ -178,7 +177,7 @@ static void __init microcode_scan_module(
      */
     for ( i = 1 /* Ignore dom0 kernel */; i < bi->nr_modules; i++ )
     {
-        if ( !test_bit(i, module_map) )
+        if ( bi->mods[i].type != BOOTMOD_UNKNOWN )
             continue;
 
         _blob_start = bootstrap_map_bm(&bi->mods[i]);
@@ -202,19 +201,18 @@ static void __init microcode_scan_module(
     }
 }
 
-static void __init microcode_grab_module(
-    unsigned long *module_map, struct boot_info *bi)
+static void __init microcode_grab_module(struct boot_info *bi)
 {
     if ( ucode_mod_idx < 0 )
         ucode_mod_idx += bi->nr_modules;
     if ( ucode_mod_idx <= 0 || ucode_mod_idx >= bi->nr_modules ||
-         !__test_and_clear_bit(ucode_mod_idx, module_map) )
+         (bi->mods[ucode_mod_idx].type != BOOTMOD_UNKNOWN) )
         goto scan;
     bi->mods[ucode_mod_idx].type = BOOTMOD_MICROCODE;
     ucode_mod = &bi->mods[ucode_mod_idx];
 scan:
     if ( ucode_scan )
-        microcode_scan_module(module_map, bi);
+        microcode_scan_module(bi);
 }
 
 static struct microcode_ops __ro_after_init ucode_ops;
@@ -818,8 +816,7 @@ static int __init early_update_cache(const void *data, size_t len)
     return rc;
 }
 
-int __init microcode_init_cache(
-    unsigned long *module_map, const struct boot_info *bi)
+int __init microcode_init_cache(const struct boot_info *bi)
 {
     int rc = 0;
 
@@ -828,7 +825,7 @@ int __init microcode_init_cache(
 
     /* Scan if microcode was not detected earlier */
     if ( !ucode_mod )
-        microcode_scan_module(module_map, bi);
+        microcode_scan_module(bi);
 
     if ( ucode_mod && !(ucode_mod->flags & BOOTMOD_FLAG_X86_CONSUMED) )
         rc = early_update_cache(bootstrap_map_bm(ucode_mod),
@@ -874,8 +871,7 @@ static int __init early_microcode_update_cpu(void)
     return microcode_update_cpu(patch, 0);
 }
 
-int __init early_microcode_init(unsigned long *module_map,
-                                struct boot_info *bi)
+int __init early_microcode_init(struct boot_info *bi)
 {
     const struct cpuinfo_x86 *c = &boot_cpu_data;
     int rc = 0;
@@ -918,7 +914,7 @@ int __init early_microcode_init(unsigned long *module_map,
         return -ENODEV;
     }
 
-    microcode_grab_module(module_map, bi);
+    microcode_grab_module(bi);
 
     if ( ucode_mod || ucode_blob.size )
         rc = early_microcode_update_cpu();
diff --git a/xen/arch/x86/include/asm/microcode.h b/xen/arch/x86/include/asm/microcode.h
index 495c8f7a7cc5..84e0eb487244 100644
--- a/xen/arch/x86/include/asm/microcode.h
+++ b/xen/arch/x86/include/asm/microcode.h
@@ -26,10 +26,8 @@ DECLARE_PER_CPU(struct cpu_signature, cpu_sig);
 void microcode_set_module(unsigned int idx);
 int microcode_update(
     XEN_GUEST_HANDLE(const_void) buf, unsigned long len, unsigned int flags);
-int early_microcode_init(
-    unsigned long *module_map, struct boot_info *bi);
-int microcode_init_cache(
-    unsigned long *module_map, const struct boot_info *bi);
+int early_microcode_init(struct boot_info *bi);
+int microcode_init_cache(const struct boot_info *bi);
 int microcode_update_one(void);
 
 #endif /* ASM_X86__MICROCODE_H */
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index e42afb0c30cb..90acd4180441 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1382,7 +1382,7 @@ void asmlinkage __init noreturn __start_xen(unsigned long mbi_p)
      * TODO: load ucode earlier once multiboot modules become accessible
      * at an earlier stage.
      */
-    early_microcode_init(module_map, bi);
+    early_microcode_init(bi);
 
     if ( xen_phys_start )
     {
@@ -1939,7 +1939,7 @@ void asmlinkage __init noreturn __start_xen(unsigned long mbi_p)
 
     timer_init();
 
-    microcode_init_cache(module_map, bi); /* Needs xmalloc() */
+    microcode_init_cache(bi); /* Needs xmalloc() */
 
     tsx_init(); /* Needs microcode.  May change HLE/RTM feature bits. */
 
