Re: [Xen-devel] [PATCH v3 07/35] OvmfPkg/XenResetVector: Saving start of day pointer for PVH guests

[Laszlo Ersek <lersek@xxxxxxxxxx>]

On 07/04/19 16:42, Anthony PERARD wrote:
> As described in the Xen PVH documentation [1], "ebx: contains the
> physical memory address where the loader has placed the boot start info
> structure". To have this pointer saved to be able to use it later in the
> PEI phase, we allocate some space in the MEMFD for it. We use 'XPVH' as
> a signature (for "Xen PVH").
> 
> [1] https://xenbits.xenproject.org/docs/unstable/misc/pvh.html
> 
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=1689
> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
> Acked-by: Laszlo Ersek <lersek@xxxxxxxxxx>
> ---
> 
> Notes:
>     v3:
>     - rename PcdXenStartOfDay* to PcdXenPvhStartOfDay*
>     - Use first available token value for those (0x17 and 0x28)

You ended up using 0x32 rather than 0x28, but that was necessary (and
correct) due to other patches meanwhile.

Also there's been a minimal comment style fix in "XenPVHMain.asm".

My Acked-by stands.

Thanks!
Laszlo

> 
>  OvmfPkg/OvmfPkg.dec                         | 3 +++
>  OvmfPkg/OvmfXen.fdf                         | 4 ++++
>  OvmfPkg/XenResetVector/XenResetVector.inf   | 3 +++
>  OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm  | 6 ++++++
>  OvmfPkg/XenResetVector/XenResetVector.nasmb | 2 ++
>  5 files changed, 18 insertions(+)
> 
> diff --git a/OvmfPkg/OvmfPkg.dec b/OvmfPkg/OvmfPkg.dec
> index 9640360f62..c2a2ebfb95 100644
> --- a/OvmfPkg/OvmfPkg.dec
> +++ b/OvmfPkg/OvmfPkg.dec
> @@ -218,6 +218,9 @@ [PcdsFixedAtBuild]
>    #  The value should be a multiple of 4KB.
>    gUefiOvmfPkgTokenSpaceGuid.PcdHighPmmMemorySize|0x400000|UINT32|0x31
>  
> +  gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtr|0x0|UINT32|0x17
> +  gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtrSize|0x0|UINT32|0x32
> +
>  [PcdsDynamic, PcdsDynamicEx]
>    gUefiOvmfPkgTokenSpaceGuid.PcdEmuVariableEvent|0|UINT64|2
>    gUefiOvmfPkgTokenSpaceGuid.PcdOvmfFlashVariablesEnable|FALSE|BOOLEAN|0x10
> diff --git a/OvmfPkg/OvmfXen.fdf b/OvmfPkg/OvmfXen.fdf
> index 43c268f6cb..49997fee9b 100644
> --- a/OvmfPkg/OvmfXen.fdf
> +++ b/OvmfPkg/OvmfXen.fdf
> @@ -172,6 +172,10 @@ [FD.MEMFD]
>  0x007000|0x001000
>  
> gEfiMdePkgTokenSpaceGuid.PcdGuidedExtractHandlerTableAddress|gUefiOvmfPkgTokenSpaceGuid.PcdGuidedExtractHandlerTableSize
>  
> +0x008000|0x001000
> +# Used by XenResetVector to communicate with XenPlatformPei
> +gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtr|gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtrSize
> +
>  0x010000|0x010000
>  
> gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamBase|gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPeiTempRamSize
>  
> diff --git a/OvmfPkg/XenResetVector/XenResetVector.inf 
> b/OvmfPkg/XenResetVector/XenResetVector.inf
> index 097fc9b5b4..46b133a834 100644
> --- a/OvmfPkg/XenResetVector/XenResetVector.inf
> +++ b/OvmfPkg/XenResetVector/XenResetVector.inf
> @@ -36,3 +36,6 @@ [BuildOptions]
>  [Pcd]
>    gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesBase
>    gUefiOvmfPkgTokenSpaceGuid.PcdOvmfSecPageTablesSize
> +
> +  gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtr
> +  gUefiOvmfPkgTokenSpaceGuid.PcdXenPvhStartOfDayStructPtrSize
> diff --git a/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm 
> b/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> index 2a17fed52f..f42df3dba2 100644
> --- a/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> +++ b/OvmfPkg/XenResetVector/Ia32/XenPVHMain.asm
> @@ -22,6 +22,12 @@ xenPVHMain:
>      ;
>      xor     esp, esp
>  
> +    ;
> +    ; Store "Start of day" struct pointer for later use
> +    ;
> +    mov     dword[PVH_SPACE (0)], ebx
> +    mov     dword[PVH_SPACE (4)], 'XPVH'
> +
>      mov     ebx, ADDR_OF(gdtr)
>      lgdt    [ebx]
>  
> diff --git a/OvmfPkg/XenResetVector/XenResetVector.nasmb 
> b/OvmfPkg/XenResetVector/XenResetVector.nasmb
> index 0dbc4f2c1d..b2cb405d54 100644
> --- a/OvmfPkg/XenResetVector/XenResetVector.nasmb
> +++ b/OvmfPkg/XenResetVector/XenResetVector.nasmb
> @@ -34,6 +34,8 @@
>  
>  %include "CommonMacros.inc"
>  
> +%define PVH_SPACE(Offset) (FixedPcdGet32 (PcdXenPvhStartOfDayStructPtr) + 
> (Offset))
> +
>  %include "PostCodes.inc"
>  
>  %ifdef DEBUG_PORT80
> 


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