Changeset 72499 in vbox for trunk/src/VBox/Devices/PC/BIOS

Timestamp:

Jun 11, 2018 10:24:01 AM (7 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

122984

Message:

BIOS: Fixed APIC disable logic, it was backwards before. No one probably noticed.

File:

• trunk/src/VBox/Devices/PC/BIOS/post.c (modified) (3 diffs)

trunk/src/VBox/Devices/PC/BIOS/post.c

@@ -125 +125 @@
 #define APIC_BASE_MSR       0x1B
 #define APICBASE_X2APIC     0x400   /* bit 10 */
-#define APICBASE_DISABLE    0x800   /* bit 11 */
+#define APICBASE_ENABLE     0x800   /* bit 11 */
 
 /*
@@ -145 +145 @@
 {
     uint64_t    base_msr;
-    uint16_t    mask;
+    uint16_t    mask_set;
+    uint16_t    mask_clr;
     uint8_t     apic_mode;
     uint32_t    cpu_id[4];
@@ -164 +165 @@
     apic_mode = inb_cmos(0x78);
 
+    mask_set = mask_clr = 0;
     if (apic_mode == APICMODE_X2APIC)
-        mask = APICBASE_X2APIC;
+        mask_set = APICBASE_X2APIC;
     else if (apic_mode == APICMODE_DISABLED)
-        mask = APICBASE_DISABLE; /** @todo r=bird: Shouldn't we clear bit 11 when disabling the APIC? */
+        mask_clr = APICBASE_ENABLE;
     else
-        mask = 0;   /* Any other setting leaves things alone. */
+        ;   /* Any other setting leaves things alone. */
 
-    if (mask) {
+    if (mask_set || mask_clr) {
         base_msr = msr_read(APIC_BASE_MSR);
-        base_msr |= mask;
+        base_msr &= ~(uint64_t)mask_clr;
+        base_msr |= mask_set;
         msr_write(base_msr, APIC_BASE_MSR);
     }