Changeset 38544 in vbox

Timestamp:

Aug 26, 2011 10:02:44 AM (14 years ago)

Author:

vboxsync

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

73696

Message:

BIOS: Cleaner initial state.

File:

• trunk/src/VBox/Devices/PC/BIOS/rombios.c (modified) (5 diffs)

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

@@ -11318 +11318 @@
 #define LVT1    0xFEE00360
 
-;; Program LVT0/LVT1 entries in the local APIC. Some Linux kernels (e.g., RHEL4
-;; SMP 32-bit) expect the entries to be unmasked in virtual wire mode.
-
-setup_lapic:
+;; Run initialization steps which must be performed in protected mode.
+;; - Program LVT0/LVT1 entries in the local APIC. Some Linux kernels (e.g., RHEL4
+;;   SMP 32-bit) expect the entries to be unmasked in virtual wire mode.
+;; - Clear the CD and NW bits in CR0; these are not relevant (except possibly
+;;    under AMD-V with nested paging) but the guest should see the right state.
+
+pmode_setup:
+  push eax
+  push esi
   pushf
   cli               ;; Interrupts would kill us!
@@ -11335 +11340 @@
   or   ah,  #0x04
   mov  [esi], eax
+  mov  eax, cr0     ;; Clear CR0.CD and CR0.NW
+  and  eax, #0x9fffffff
+  mov  cr0, eax
   call pmode_exit
   popf
+  pop  esi
+  pop  eax
   ret
 
@@ -11466 +11476 @@
 
   cli
-  mov  ax, #0x7700
+  mov  ax, #0x7C00
   mov  sp, ax
   xor  ax, ax
@@ -11518 +11528 @@
   call _log_bios_start
 
+  call pmode_setup
+
   ;; set all interrupts to default handler
   xor  bx, bx         ;; offset index
@@ -11712 +11724 @@
   call pcibios_init_irqs
 #endif
-  call setup_lapic
   call rom_scan