Re: [PATCH v2 3/4] ArmVirtPkg/NorFlashQemuLib: disregard our primary FV

[Laszlo Ersek <lersek@redhat.com>]

On 11/30/18 12:28, Ard Biesheuvel wrote:
> The primary FV contains the firmware boot image, which is not
> runtime updatable in our case. So exposing it to the NOR flash
> driver is undesirable, since it may attempt to modify the NOR
> flash contents. It is also rather pointless, since we don't
> keep anything there that we care to expose. (the SEC and PEI
> phase modules are not executable from DXE context, and the
> contents of the embedded DXE phase FV are exposed by the DXE
> core directly via the FVB2 protocol)
> 
> So let's disregard the NOR flash block that covers the primary
> FV.
> 
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
>  ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf |  5 +++++
>  ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c   | 13 +++++++++++--
>  2 files changed, 16 insertions(+), 2 deletions(-)
> 
> diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf
> index d86ff36dbd58..c5752a243e6b 100644
> --- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf
> +++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.inf
> @@ -28,6 +28,7 @@ [Sources.common]
>  [Packages]
>    MdePkg/MdePkg.dec
>    ArmPlatformPkg/ArmPlatformPkg.dec
> +  ArmPkg/ArmPkg.dec
>    ArmVirtPkg/ArmVirtPkg.dec
>  
>  [LibraryClasses]
> @@ -40,3 +41,7 @@ [Protocols]
>  
>  [Depex]
>    gFdtClientProtocolGuid
> +
> +[Pcd]
> +  gArmTokenSpaceGuid.PcdFvBaseAddress
> +  gArmTokenSpaceGuid.PcdFvSize
> diff --git a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
> index 2678f57eaaad..d238e39a59f1 100644
> --- a/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
> +++ b/ArmVirtPkg/Library/NorFlashQemuLib/NorFlashQemuLib.c
> @@ -75,13 +75,22 @@ NorFlashPlatformGetDevices (
>        Size = SwapBytes64 (ReadUnaligned64 ((VOID *)&Reg[2]));
>        Reg += 4;
>  
> +      PropSize -= 4 * sizeof (UINT32);
> +
> +      //
> +      // Disregard any flash devices that overlap with the primary FV.
> +      // The firmware is not updatable from inside the guest anyway.
> +      //
> +      if ((PcdGet64 (PcdFvBaseAddress) + PcdGet32 (PcdFvSize) > Base) &&
> +          (Base + Size) > PcdGet64 (PcdFvBaseAddress)) {
> +        continue;
> +      }
> +
>        mNorFlashDevices[Num].DeviceBaseAddress = (UINTN)Base;
>        mNorFlashDevices[Num].RegionBaseAddress = (UINTN)Base;
>        mNorFlashDevices[Num].Size              = (UINTN)Size;
>        mNorFlashDevices[Num].BlockSize         = QEMU_NOR_BLOCK_SIZE;
>        Num++;
> -
> -      PropSize -= 4 * sizeof (UINT32);
>      }
>    }
>  
> 

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