OvmfPkg/ResetVector: Depend on PCD values of the page tables.

Currently, the value of the page tables' address is hard-coded in the
ResetVector. This patch replaces these values with a PCD dependency.

A check for the size has been added to alert the developer to rewrite
the ASM according to the new size, if it has been changed.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Marvin Haeuser <Marvin.Haeuser@outlook.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Tested-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

3 files changed, 24 insertions, 11 deletions

diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
index b5a4cf8d71..6201cad1f5 100644
--- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
+++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
@@ -44,10 +44,11 @@ BITS    32
 SetCr3ForPageTables64:

 

     ;

-    ; For OVMF, build some initial page tables at 0x800000-0x806000.

+    ; For OVMF, build some initial page tables at

+    ; PcdOvmfSecPageTablesBase - (PcdOvmfSecPageTablesBase + 0x6000).

     ;

-    ; This range should match with PcdOvmfSecPageTablesBase and

-    ; PcdOvmfSecPageTablesSize which are declared in the FDF files.

+    ; This range should match with PcdOvmfSecPageTablesSize which is

+    ; declared in the FDF files.

     ;

     ; At the end of PEI, the pages tables will be rebuilt into a

     ; more permanent location by DxeIpl.

@@ -56,21 +57,21 @@ SetCr3ForPageTables64:
     mov     ecx, 6 * 0x1000 / 4

     xor     eax, eax

 clearPageTablesMemoryLoop:

-    mov     dword[ecx * 4 + 0x800000 - 4], eax

+    mov     dword[ecx * 4 + PT_ADDR (0) - 4], eax

     loop    clearPageTablesMemoryLoop

 

     ;

     ; Top level Page Directory Pointers (1 * 512GB entry)

     ;

-    mov     dword[0x800000], 0x801000 + PAGE_PDP_ATTR

+    mov     dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDP_ATTR

 

     ;

     ; Next level Page Directory Pointers (4 * 1GB entries => 4GB)

     ;

-    mov     dword[0x801000], 0x802000 + PAGE_PDP_ATTR

-    mov     dword[0x801008], 0x803000 + PAGE_PDP_ATTR

-    mov     dword[0x801010], 0x804000 + PAGE_PDP_ATTR

-    mov     dword[0x801018], 0x805000 + PAGE_PDP_ATTR

+    mov     dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDP_ATTR

+    mov     dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDP_ATTR

+    mov     dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDP_ATTR

+    mov     dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDP_ATTR

 

     ;

     ; Page Table Entries (2048 * 2MB entries => 4GB)

@@ -81,13 +82,13 @@ pageTableEntriesLoop:
     dec     eax

     shl     eax, 21

     add     eax, PAGE_2M_PDE_ATTR

-    mov     [ecx * 8 + 0x802000 - 8], eax

+    mov     [ecx * 8 + PT_ADDR (0x2000 - 8)], eax

     loop    pageTableEntriesLoop

 

     ;

     ; Set CR3 now that the paging structures are available

     ;

-    mov     eax, 0x800000

+    mov     eax, PT_ADDR (0)

     mov     cr3, eax

 

     OneTimeCallRet SetCr3ForPageTables64

diff --git a/OvmfPkg/ResetVector/ResetVector.inf b/OvmfPkg/ResetVector/ResetVector.inf
index 46610d243e..d1e5d4d9bd 100644
--- a/OvmfPkg/ResetVector/ResetVector.inf
+++ b/OvmfPkg/ResetVector/ResetVector.inf
@@ -29,9 +29,14 @@
   ResetVector.nasmb

 

 [Packages]

+  OvmfPkg/OvmfPkg.dec

   MdePkg/MdePkg.dec

   UefiCpuPkg/UefiCpuPkg.dec

 

 [BuildOptions]

    *_*_IA32_NASMB_FLAGS = -I$(WORKSPACE)/UefiCpuPkg/ResetVector/Vtf0/

    *_*_X64_NASMB_FLAGS = -I$(WORKSPACE)/UefiCpuPkg/ResetVector/Vtf0/

+

+[Pcd]

+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase

+  gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesSize

diff --git a/OvmfPkg/ResetVector/ResetVector.nasmb b/OvmfPkg/ResetVector/ResetVector.nasmb
index 31ac06ae4a..29cbad3677 100644
--- a/OvmfPkg/ResetVector/ResetVector.nasmb
+++ b/OvmfPkg/ResetVector/ResetVector.nasmb
@@ -53,6 +53,13 @@
 %include "Ia32/SearchForSecEntry.asm"

 

 %ifdef ARCH_X64

+  #include <AutoGen.h>

+

+  %if (FixedPcdGet32 (PcdOvmfSecPageTablesSize) != 0x6000)

+    %error "This implementation inherently depends on PcdOvmfSecPageTablesSize"

+  %endif

+

+  %define PT_ADDR(Offset) (FixedPcdGet32 (PcdOvmfSecPageTablesBase) + (Offset))

 %include "Ia32/Flat32ToFlat64.asm"

 %include "Ia32/PageTables64.asm"

 %endif