Re: [edk2-devel] [PATCH v2 3/5] OvmfPkg/ResetVector: improve page table flag names

["Laszlo Ersek" <lersek@redhat.com>]

On 1/30/24 13:32, Gerd Hoffmann wrote:
> Add comments, rename some of the PAGE_* flags and combined attributes.
> Specifically use "LARGEPAGE" instead of "2M" because that bit is used
> for both 2M and 1G large pages.
> 
> Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> ---
>  OvmfPkg/ResetVector/Ia32/PageTables64.asm | 39 +++++++++++++----------
>  1 file changed, 22 insertions(+), 17 deletions(-)
> 
> diff --git a/OvmfPkg/ResetVector/Ia32/PageTables64.asm b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> index 317cad430f29..6fec6f2beeea 100644
> --- a/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> +++ b/OvmfPkg/ResetVector/Ia32/PageTables64.asm
> @@ -10,6 +10,7 @@
>  
>  BITS    32
>  
> +; common for all levels
>  %define PAGE_PRESENT            0x01
>  %define PAGE_READ_WRITE         0x02
>  %define PAGE_USER_SUPERVISOR    0x04
> @@ -17,25 +18,29 @@ BITS    32
>  %define PAGE_CACHE_DISABLE     0x010
>  %define PAGE_ACCESSED          0x020
>  %define PAGE_DIRTY             0x040
> -%define PAGE_PAT               0x080
>  %define PAGE_GLOBAL           0x0100
> -%define PAGE_2M_MBO            0x080
> -%define PAGE_2M_PAT          0x01000
> +
> +; page table entries (level 1)
> +%define PAGE_PTE_PAT           0x080
> +
> +; page directory entries (level 2+)
> +%define PAGE_PDE_LARGEPAGE     0x080
> +%define PAGE_PDE_PAT         0x01000

Interesting: PAGE_PAT and PAGE_2M_PAT appear unused!

But the patch is still fine; thank you for it!

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Laszlo


>  
>  %define PAGE_4K_PDE_ATTR (PAGE_ACCESSED + \
>                            PAGE_DIRTY + \
>                            PAGE_READ_WRITE + \
>                            PAGE_PRESENT)
>  
> -%define PAGE_2M_PDE_ATTR (PAGE_2M_MBO + \
> -                          PAGE_ACCESSED + \
> -                          PAGE_DIRTY + \
> -                          PAGE_READ_WRITE + \
> -                          PAGE_PRESENT)
> +%define PAGE_PDE_LARGEPAGE_ATTR (PAGE_PDE_LARGEPAGE + \
> +                                 PAGE_ACCESSED + \
> +                                 PAGE_DIRTY + \
> +                                 PAGE_READ_WRITE + \
> +                                 PAGE_PRESENT)
>  
> -%define PAGE_PDP_ATTR (PAGE_ACCESSED + \
> -                       PAGE_READ_WRITE + \
> -                       PAGE_PRESENT)
> +%define PAGE_PDE_DIRECTORY_ATTR (PAGE_ACCESSED + \
> +                                 PAGE_READ_WRITE + \
> +                                 PAGE_PRESENT)
>  
>  %define TDX_BSP         1
>  %define TDX_AP          2
> @@ -84,19 +89,19 @@ clearPageTablesMemoryLoop:
>      ;
>      ; Top level Page Directory Pointers (1 * 512GB entry)
>      ;
> -    mov     dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDP_ATTR
> +    mov     dword[PT_ADDR (0)], PT_ADDR (0x1000) + PAGE_PDE_DIRECTORY_ATTR
>      mov     dword[PT_ADDR (4)], edx
>  
>      ;
>      ; Next level Page Directory Pointers (4 * 1GB entries => 4GB)
>      ;
> -    mov     dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDP_ATTR
> +    mov     dword[PT_ADDR (0x1000)], PT_ADDR (0x2000) + PAGE_PDE_DIRECTORY_ATTR
>      mov     dword[PT_ADDR (0x1004)], edx
> -    mov     dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDP_ATTR
> +    mov     dword[PT_ADDR (0x1008)], PT_ADDR (0x3000) + PAGE_PDE_DIRECTORY_ATTR
>      mov     dword[PT_ADDR (0x100C)], edx
> -    mov     dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDP_ATTR
> +    mov     dword[PT_ADDR (0x1010)], PT_ADDR (0x4000) + PAGE_PDE_DIRECTORY_ATTR
>      mov     dword[PT_ADDR (0x1014)], edx
> -    mov     dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDP_ATTR
> +    mov     dword[PT_ADDR (0x1018)], PT_ADDR (0x5000) + PAGE_PDE_DIRECTORY_ATTR
>      mov     dword[PT_ADDR (0x101C)], edx
>  
>      ;
> @@ -107,7 +112,7 @@ pageTableEntriesLoop:
>      mov     eax, ecx
>      dec     eax
>      shl     eax, 21
> -    add     eax, PAGE_2M_PDE_ATTR
> +    add     eax, PAGE_PDE_LARGEPAGE_ATTR
>      mov     [ecx * 8 + PT_ADDR (0x2000 - 8)], eax
>      mov     [(ecx * 8 + PT_ADDR (0x2000 - 8)) + 4], edx
>      loop    pageTableEntriesLoop



-=-=-=-=-=-=-=-=-=-=-=-
Groups.io Links: You receive all messages sent to this group.
View/Reply Online (#114815): https://edk2.groups.io/g/devel/message/114815
Mute This Topic: https://groups.io/mt/104052210/7686176
Group Owner: devel+owner@edk2.groups.io
Unsubscribe: https://edk2.groups.io/g/devel/leave/12367111/7686176/1913456212/xyzzy [rebecca@openfw.io]
-=-=-=-=-=-=-=-=-=-=-=-