[edk2-devel] [PATCH v6 5/5] OvmfPkg/RiscVVirt: Override for RV CPU Features

Dhaval Sharma posted 5 patches 2 years, 3 months ago
There is a newer version of this series
[edk2-devel] [PATCH v6 5/5] OvmfPkg/RiscVVirt: Override for RV CPU Features
Posted by Dhaval Sharma 2 years, 3 months ago
This PCD provides a way for platform to override any
HW features that are default enabled by previous stages
of FW (like OpenSBI). For the case where previous/prev
stage has disabled the feature, this override is not
useful and its usage should be avoided.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Sunil V L <sunilvl@ventanamicro.com>
Cc: Andrei Warkentin <andrei.warkentin@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>

Signed-off-by: Dhaval Sharma <dhaval@rivosinc.com>
---

Notes:
    v2:
    - Modify PCD name according to changes made in Baselib implementation
    V1:
    - Introduce PCD for platform

 OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc | 1 +
 1 file changed, 1 insertion(+)

diff --git a/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc b/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc
index fe320525153f..5d66f7fe6ae6 100644
--- a/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc
+++ b/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc
@@ -203,6 +203,7 @@ [PcdsFeatureFlag]
   gEfiMdeModulePkgTokenSpaceGuid.PcdInstallAcpiSdtProtocol|TRUE
 
 [PcdsFixedAtBuild.common]
+  gEfiMdePkgTokenSpaceGuid.PcdRiscVFeatureOverride|0
   gEfiMdePkgTokenSpaceGuid.PcdMaximumUnicodeStringLength|1000000
   gEfiMdePkgTokenSpaceGuid.PcdMaximumAsciiStringLength|1000000
   gEfiMdePkgTokenSpaceGuid.PcdMaximumLinkedListLength|0
-- 
2.39.2



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Re: [edk2-devel] [PATCH v6 5/5] OvmfPkg/RiscVVirt: Override for RV CPU Features
Posted by Laszlo Ersek 2 years, 3 months ago
On 10/21/23 19:33, Dhaval Sharma wrote:
> This PCD provides a way for platform to override any
> HW features that are default enabled by previous stages
> of FW (like OpenSBI). For the case where previous/prev
> stage has disabled the feature, this override is not
> useful and its usage should be avoided.
> 
> Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
> Cc: Jiewen Yao <jiewen.yao@intel.com>
> Cc: Jordan Justen <jordan.l.justen@intel.com>
> Cc: Gerd Hoffmann <kraxel@redhat.com>
> Cc: Sunil V L <sunilvl@ventanamicro.com>
> Cc: Andrei Warkentin <andrei.warkentin@intel.com>
> Cc: Laszlo Ersek <lersek@redhat.com>
> 
> Signed-off-by: Dhaval Sharma <dhaval@rivosinc.com>
> ---
> 
> Notes:
>     v2:
>     - Modify PCD name according to changes made in Baselib implementation
>     V1:
>     - Introduce PCD for platform
> 
>  OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc b/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc
> index fe320525153f..5d66f7fe6ae6 100644
> --- a/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc
> +++ b/OvmfPkg/RiscVVirt/RiscVVirt.dsc.inc
> @@ -203,6 +203,7 @@ [PcdsFeatureFlag]
>    gEfiMdeModulePkgTokenSpaceGuid.PcdInstallAcpiSdtProtocol|TRUE
>  
>  [PcdsFixedAtBuild.common]
> +  gEfiMdePkgTokenSpaceGuid.PcdRiscVFeatureOverride|0
>    gEfiMdePkgTokenSpaceGuid.PcdMaximumUnicodeStringLength|1000000
>    gEfiMdePkgTokenSpaceGuid.PcdMaximumAsciiStringLength|1000000
>    gEfiMdePkgTokenSpaceGuid.PcdMaximumLinkedListLength|0

I propose to only clear the least significant bit in the PCD -- that is,
say 0xFFFFFFFFFFFFFFFE here.

But, it's up to you. Either way:

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



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