Re: [PATCH v4] OvmfPkg/ResetVector: Depend on PCD values of the page tables.

[Laszlo Ersek <lersek@redhat.com>]

On 11/04/16 23:38, Jordan Justen wrote:
> On 2016-11-04 15:27:48, Laszlo Ersek wrote:
>> On 11/04/16 14:32, Marvin Häuser wrote:
>>> 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>
>>> ---
>>>  OvmfPkg/ResetVector/Ia32/PageTables64.asm | 23 ++++++++++----------
>>>  OvmfPkg/ResetVector/ResetVector.inf       |  5 +++++
>>>  OvmfPkg/ResetVector/ResetVector.nasmb     |  7 ++++++
>>>  3 files changed, 24 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
>>> index b5a4cf8d7187..6201cad1f5dc 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 46610d243ecf..d1e5d4d9bdea 100644
>>> --- a/OvmfPkg/ResetVector/ResetVector.inf
>>> +++ b/OvmfPkg/ResetVector/ResetVector.inf
>>> @@ -29,9 +29,14 @@ [Sources]
>>>    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 31ac06ae4a8c..29cbad367711 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
>>>
>>
>> I compared this patch to the one that I worked out / simplified from
>> your v2 patch and posted as our shared v3:
>>
>> https://lists.01.org/pipermail/edk2-devel/2016-November/004140.html
>>
>> The differences are cosmetic.
>>
>> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
>> Tested-by: Laszlo Ersek <lersek@redhat.com>
>>
>> I could commit & push this now (I could even find the energy in me for
>> that), but I'd like Jordan to okay the patch as well, in this form.
>>
> 
> Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

Thanks, pushed as commit 73d66c5871cc.

Thank you for the contribution, Marvin!
Laszlo