x86, amd: Don't probe for extended APIC ID if APICs are disabled

If we've logically disabled apics, don't probe the PCI space for the AMD extended APIC ID. [ Impact: prevent boot crash under Xen. ] Signed-off-by: Jeremy Fitzhardinge <[email protected]> Reported-by: Bastian Blank <[email protected]> Signed-off-by: H. Peter Anvin <[email protected]>
yshchan · Jul 22, 2009 · 2cb0786 · 2cb0786
1 parent 6effa8f
commit 2cb0786
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
@@ -356,7 +356,7 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
 #endif
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI)
 	/* check CPU config space for extended APIC ID */
-	if (c->x86 >= 0xf) {
+	if (cpu_has_apic && c->x86 >= 0xf) {
 		unsigned int val;
 		val = read_pci_config(0, 24, 0, 0x68);
 		if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))