Re: [edk2-devel] [PATCH v2 2/5] MdeMoudlePkg: introduce new PCD for Acpi/rsdp

["Jianyong Wu" <jianyong.wu@arm.com>]

Hi Laszlo,

> -----Original Message-----
> From: Laszlo Ersek <lersek@redhat.com>
> Sent: Wednesday, May 19, 2021 2:17 PM
> To: devel@edk2.groups.io; Jianyong Wu <Jianyong.Wu@arm.com>;
> ardb+tianocore@kernel.org; Sami Mujawar <Sami.Mujawar@arm.com>
> Cc: hao.a.wu@intel.com; Justin He <Justin.He@arm.com>; Jian J Wang
> <jian.j.wang@intel.com>
> Subject: Re: [edk2-devel] [PATCH v2 2/5] MdeMoudlePkg: introduce new
> PCD for Acpi/rsdp
>
> On 05/17/21 08:50, Jianyong Wu wrote:
> > As there is lack of a machnism in Cloud Hypervisor to pass the base
> > address of Rsdp in Acpi, so a PCD varialbe is introduced here to feed
> > it.
> >
> > Cc: Hao A Wu <hao.a.wu@intel.com>
> > Cc: Jian J Wang <jian.j.wang@intel.com>
> > Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
> > ---
> >  MdeModulePkg/MdeModulePkg.dec | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/MdeModulePkg/MdeModulePkg.dec
> > b/MdeModulePkg/MdeModulePkg.dec index
> 148395511034..4c8baac35a9e
> > 100644
> > --- a/MdeModulePkg/MdeModulePkg.dec
> > +++ b/MdeModulePkg/MdeModulePkg.dec
> > @@ -910,6 +910,13 @@ [PcdsFixedAtBuild]
> >    # @Expression 0x80000001 |
> (gEfiMdeModulePkgTokenSpaceGuid.PcdLoadModuleAtFixAddressEnable
> == 0xFFFFFFFFFFFFFFFF ||
> gEfiMdeModulePkgTokenSpaceGuid.PcdLoadModuleAtFixAddressEnable <=
> 0x0FFFFFFFFFFFFFFF)
> >
> >
> gEfiMdeModulePkgTokenSpaceGuid.PcdLoadModuleAtFixAddressEnable|0|
> UINT6
> > 4|0x30001015
> >
> > +  ##
> > +  # This is the physical address of rsdp which is the core struct of Acpi.
> > +  # Some hypervisor may has no way to pass rsdp address to the guest,
> > + so a PCD  # is worth for those.
> > +  #
> > +
> > +
> gEfiMdeModulePkgTokenSpaceGuid.PcdAcpiRsdpBaseAddress|0x0|UINT64
> |0x3
> > + 0001056
> > +
> >    ## Progress Code for OS Loader LoadImage start.<BR><BR>
> >    #  PROGRESS_CODE_OS_LOADER_LOAD   =
> (EFI_SOFTWARE_DXE_BS_DRIVER | (EFI_OEM_SPECIFIC | 0x00000000)) =
> 0x03058000<BR>
> >    # @Prompt Progress Code for OS Loader LoadImage start.
> >
>
> This PCD is not useful enough to be placed in MdeModulePkg -- it is only
> used in the next two patches, which are for ArmVirtPkg.
>
> (1) Therefore, please add the PCD to the "ArmVirtPkg.dec" file.
>
> (2) The PCD should arguably refer to "CloudHv" in the name.
>
> (3) In my opinion, this patch (once reimplemented for ArmVirtPkg.dec)
> should be squashed into the CloudHvAcpiPlatformDxe patch. The PCD is
> being introduced *for* CloudHvAcpiPlatformDxe, and *only* for that driver.
> In such cases, we usually keep the DEC modifications in the same patch as
> the driver addition, assuming the PCD goes in the same package as the driver.
>
> (4) "some hypervisor" in the DEC comment is bogus. Please be as explicit
> about the use case as possible.

OK,  that's better.

Thanks
Jianyong

>
> Thanks
> Laszlo

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