Re: [edk2-devel] [PATCH EDK2 v1 1/1] MdeModulePkg: Modify PCD default value

["Wu, Hao A" <hao.a.wu@intel.com>]

(Add Ray)
Hello Ray, do you have comments on changing the default value of PcdSrIovSystemPageSize from 0x1 to 0x10?

I am not quite sure if there will be compatibility issue for this change.

Best Regards,
Hao Wu

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of
> wenyi,xie via groups.io
> Sent: Thursday, July 15, 2021 8:25 PM
> To: devel@edk2.groups.io; Wang, Jian J <jian.j.wang@intel.com>; Wu, Hao A
> <hao.a.wu@intel.com>
> Cc: songdongkuang@huawei.com; wanghuiqiang@huawei.com;
> xiewenyi2@huawei.com
> Subject: [edk2-devel] [PATCH EDK2 v1 1/1] MdeModulePkg: Modify PCD
> default value
> 
> From: "wenyi.xie" <xiewenyi2@huawei.com>
> 
> The default value of PcdSrIovSystemPageSize is 0x1, it means the memory
> BAR is 4KB alignment. When page size of OS is set to 64KB, as the resource
> partitions are different between OS and BIOS, it will cause pcie failture. And if
> 52 bit physical address need to be supported, page size should also be set to
> 64KB alignment.
> So modify the default vaule of PcdSrIovSystemPageSize to 0x10 can meet the
> requirement above. And even if the OS is 4KB alignment, new value of PCD is
> compatible for this situation.
> 
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Cc: Hao A Wu <hao.a.wu@intel.com>
> Signed-off-by: Wenyi Xie <xiewenyi2@huawei.com>
> ---
>  MdeModulePkg/MdeModulePkg.dec | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/MdeModulePkg/MdeModulePkg.dec
> b/MdeModulePkg/MdeModulePkg.dec index ad84421cf3..426ea1b6cc
> 100644
> --- a/MdeModulePkg/MdeModulePkg.dec
> +++ b/MdeModulePkg/MdeModulePkg.dec
> @@ -1853,7 +1853,7 @@
>    #  BIT0 set indicates 4KB alignment<BR>
>    #  BIT1 set indicates 8KB alignment<BR>
>    # @Prompt SRIOV system page size.
> -
> gEfiMdeModulePkgTokenSpaceGuid.PcdSrIovSystemPageSize|0x1|UINT32|
> 0x10000047
> +
> +
> gEfiMdeModulePkgTokenSpaceGuid.PcdSrIovSystemPageSize|0x10|UINT32
> |0x10
> + 000047
> 
>    ## SMBIOS version.
>    # @Prompt SMBIOS version.
> --
> 2.20.1.windows.1
> 
> 
> 
> 
>