Merge tag 'x86_urgent_for_7.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Dave Hansen:
 "These are fixes for some older AMD device topology and machine check
  issues. But, they are issues that are affecting real users and aren't
  just cleaning up AI drive-by reports.

  These is coming a wee bit later than the usual Sundays because of a
  late breaking issue with one of the patches which is now temporarily
  kicked out"

* tag 'x86_urgent_for_7.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/MCE/AMD: Fix inverted interrupt enablement during storm handling
  x86/amd_node: Fix potential NULL pointer dereference
  x86/amd_node: Avoid divide by zero on virtualized systems

arch/x86/kernel/amd_node.c

@@ -38,7 +38,6 @@ static struct pci_dev **amd_roots;
 
 /* Protect the PCI config register pairs used for SMN. */
 static DEFINE_MUTEX(smn_mutex);
-static bool smn_exclusive;
 
 #define SMN_INDEX_OFFSET	0x60
 #define SMN_DATA_OFFSET		0x64
@@ -91,11 +90,16 @@ static int __amd_smn_rw(u8 i_off, u8 d_off, u16 node, u32 address, u32 *value, b
 	if (node >= amd_num_nodes())
 		return err;
 
-	root = amd_roots[node];
-	if (!root)
+	/*
+	 * Uninitialized amd_roots indicates pci_request_config_region_exclusive()
+	 * didn't run or failed and thus the kernel cannot rely on having
+	 * exclusive access to SMN registers so prevent that.
+	 */
+	if (!amd_roots)
 		return err;
 
-	if (!smn_exclusive)
+	root = amd_roots[node];
+	if (!root)
 		return err;
 
 	guard(mutex)(&smn_mutex);
@@ -287,6 +291,11 @@ static int __init amd_smn_init(void)
 		return -ENOMEM;
 
 	roots_per_node = num_roots / num_nodes;
+	if (!roots_per_node) {
+		if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
+			pr_warn(FW_BUG "Error detecting roots per node.\n");
+		roots_per_node = 1;
+	}
 
 	count = 0;
 	node = 0;
@@ -308,8 +317,6 @@ static int __init amd_smn_init(void)
 		debugfs_create_file("value",	0600, debugfs_dir, NULL, &smn_value_fops);
 	}
 
-	smn_exclusive = true;
-
 	return 0;
 }
 

arch/x86/kernel/cpu/mce/amd.c

@@ -865,7 +865,7 @@ static void amd_deferred_error_interrupt(void)
 
 void mce_amd_handle_storm(unsigned int bank, bool on)
 {
-	threshold_restart_bank(bank, on);
+	threshold_restart_bank(bank, !on);
 }
 
 static void amd_reset_thr_limit(unsigned int bank)