diff options
| author |   Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
|---|---|---|
| committer | Angelos Mouzakitis <a.mouzakitis@virtualopensystems.com> | 2023-10-10 14:33:42 +0000 |
| commit | af1a266670d040d2f4083ff309d732d648afba2a (patch) | |
| tree | 2fc46203448ddcc6f81546d379abfaeb323575e9 /roms/edk2/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm | |
| parent | e02cda008591317b1625707ff8e115a4841aa889 (diff) | |
Change-Id: Iaf8d18082d3991dec7c0ebbea540f092188eb4ec
Diffstat (limited to 'roms/edk2/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm')
| -rw-r--r-- | roms/edk2/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/roms/edk2/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm b/roms/edk2/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm new file mode 100644 index 000000000..2df0f12e1 --- /dev/null +++ b/roms/edk2/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm @@ -0,0 +1,84 @@ +;------------------------------------------------------------------------------
+; @file
+; An entry point use by Xen when a guest is started in PVH mode.
+;
+; Copyright (c) 2019, Citrix Systems, Inc.
+;
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+BITS 32
+
+xenPVHMain:
+ ;
+ ; 'BP' to indicate boot-strap processor
+ ;
+ mov di, 'BP'
+
+ ;
+ ; Store "Start of day" struct pointer for later use
+ ;
+ mov dword[PVH_SPACE (0)], ebx
+ mov dword[PVH_SPACE (4)], 'XPVH'
+
+ ;
+ ; calculate delta between build-addr and run position
+ ;
+ mov esp, PVH_SPACE(16) ; create a temporary stack
+ call .delta
+.delta:
+ pop edx ; get addr of .delta
+ sub edx, ADDR_OF(.delta) ; calculate delta
+
+ ;
+ ; Find address of GDT and gdtr and fix the later
+ ;
+ mov ebx, ADDR_OF(gdtr)
+ add ebx, edx ; add delta gdtr
+ mov eax, ADDR_OF(GDT_BASE)
+ add eax, edx ; add delta to GDT_BASE
+ mov dword[ebx + 2], eax ; fix GDT_BASE addr in gdtr
+ lgdt [ebx]
+
+ mov eax, SEC_DEFAULT_CR0
+ mov cr0, eax
+
+ ;
+ ; push return addr to the stack, then return far
+ ;
+ push dword LINEAR_CODE_SEL ; segment to select
+ mov eax, ADDR_OF(.jmpToNewCodeSeg) ; return addr
+ add eax, edx ; add delta to return addr
+ push eax
+ retf
+.jmpToNewCodeSeg:
+
+ mov eax, SEC_DEFAULT_CR4
+ mov cr4, eax
+
+ mov ax, LINEAR_SEL
+ mov ds, ax
+ mov es, ax
+ mov fs, ax
+ mov gs, ax
+ mov ss, ax
+
+ ;
+ ; ESP will be used as initial value of the EAX register
+ ; in Main.asm
+ ;
+ xor esp, esp
+
+ ;
+ ; parameter for Flat32SearchForBfvBase
+ ;
+ mov eax, ADDR_OF(fourGigabytes)
+ add eax, edx ; add delta
+
+ ;
+ ; Jump to the main routine of the pre-SEC code
+ ; skiping the 16-bit part of the routine and
+ ; into the 32-bit flat mode part
+ ;
+ OneTimeCallRet TransitionFromReal16To32BitFlat
|