Re: 回复: [edk2-devel] [PATCH v4 13/14] MdeModulePkg/VariableStandaloneMm: Set PcdFlashNvStorageVariableBase to Pcd

[Ilias Apalodimas]

On Thu, Feb 18, 2021 at 11:13:21AM +0800, gaoliming wrote:
> I suggest to directly change [FixedPcd] to [Pcd] section. All Pcds can
> support FixedAtBuild and PatchableInModule. 

We can, but is there a reason to do that?
Wouldn't we be better of being more strict on the Pcd context we define for
each variable?

The values that were swapped from FixedPcd to Pcd are expected to change in
runtime, while the rest don't.

Thanks
/Ilias

> 
> With this change, Reviewed-by: Liming Gao <gaoliming at byosoft.com.cn>
> 
> Thanks
> Liming
> > -----邮件原件-----
> > 发件人: bounce+27952+71734+4905953+8761045 at groups.io
> > <bounce+27952+71734+4905953+8761045 at groups.io> 代表 Sughosh Ganu
> > 发送时间: 2021年2月17日 19:27
> > 收件人: devel at edk2.groups.io
> > 抄送: Sami Mujawar <sami.mujawar at arm.com>; Ilias Apalodimas
> > <ilias.apalodimas at linaro.org>; Ard Biesheuvel <ardb+tianocore at kernel.org>
> > 主题: [edk2-devel] [PATCH v4 13/14] MdeModulePkg/VariableStandaloneMm:
> > Set PcdFlashNvStorageVariableBase to Pcd
> > 
> > From: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > 
> > Instead of running StMM in SPM, OP-TEE creates a new secure partition,
> > which emulates SPM and isolates StMM from the rest of the Trusted
> > Applications (TAs). We can then compile StMM as an FD image and run it
> > in OP-TEE. With the addition of a new RPMB driver, we can leverage OP-TEE
> > and store variables to an RPMB device.
> > 
> > Since EDK2 upper layers expect byte addressable code, for the RPMB to
> > work, we need to allocate memory and sync it with the hardware on
> > read/writes. Since DynamicPCDs are not supported in that context we
> > can only use PatchablePCDs. So let's switch them to Pcd instead of
> > FixedPcd and accomodate the new driver.
> > 
> > Signed-off-by: Ilias Apalodimas <ilias.apalodimas at linaro.org>
> > Reviewed-by: Sami Mujawar <sami.mujawar at arm.com>
> > ---
> > 
> > Changes since V3: None
> > 
> >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.inf
> > | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> > 
> > diff --git
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.in
> > f
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.in
> > f
> > index fada0bf3c5..2a25fbdada 100644
> > ---
> > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.in
> > f
> > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableStandaloneMm.in
> > f
> > @@ -119,10 +119,12 @@
> >    ## SOMETIMES_PRODUCES   ## Variable:L"VarErrorFlag"
> >    gEdkiiVarErrorFlagGuid
> > 
> > -[FixedPcd]
> > -  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
> > ## CONSUMES
> > +[Pcd]
> >    gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase
> > ## SOMETIMES_CONSUMES
> >    gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableBase64
> > ## CONSUMES
> > +  gEfiMdeModulePkgTokenSpaceGuid.PcdFlashNvStorageVariableSize
> > ## CONSUMES
> > +
> > +[FixedPcd]
> >    gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVariableSize
> > ## CONSUMES
> >    gEfiMdeModulePkgTokenSpaceGuid.PcdMaxAuthVariableSize
> > ## CONSUMES
> >    gEfiMdeModulePkgTokenSpaceGuid.PcdMaxVolatileVariableSize
> > ## CONSUMES
> > --
> > 2.17.1
> > 
> > 
> > 
> > 
> > 
> 
> 
> 
> 
> 
> 
> 
> 


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