Re: [PATCH v2 11/12] ArmVirtPkg/PlatformHasAcpiDtDxe: don't expose DT if QEMU provides ACPI

[Ard Biesheuvel <ard.biesheuvel@linaro.org>]

On 17 March 2017 at 20:47, Laszlo Ersek <lersek@redhat.com> wrote:
> This will let QEMU's "-no-acpi" option exclusively expose DT vs. ACPI to
> the guest. Showing both is never needed (it is actually detrimental to the
> adoption of standards, such as SBSA / SBBR).
>
> * Without "-no-acpi", the firmware logs (from PlatformHasAcpiDtDxe)
>
>> Found FwCfg @ 0x9020008/0x9020000
>> Found FwCfg DMA @ 0x9020010
>> InstallProtocolInterface: [EdkiiPlatformHasAcpiProtocol] 0
>
> plus the usual messages. Later the guest kernel logs
>
>> [    0.000000] efi:  SMBIOS 3.0=0x13bdb0000  ACPI 2.0=0x138440000
>
> before it lists the ACPI tables one by one.
>
> * With "-no-acpi", the firmware logs:
>
>> PlatformHasAcpiDtDxe | Found FwCfg @ 0x9020008/0x9020000
>> PlatformHasAcpiDtDxe | Found FwCfg DMA @ 0x9020010
>> PlatformHasAcpiDtDxe | InstallProtocolInterface:
>> PlatformHasAcpiDtDxe | [EdkiiPlatformHasDeviceTreeProtocol] 0
>> FdtClientDxe         | OnPlatformHasDeviceTree: exposing DTB @
>> FdtClientDxe         | 0x13FFBF000 to OS
>> ...
>> DXE_CORE             | Driver [AcpiTableDxe] was discovered but not
>> DXE_CORE             | loaded!!
>> DXE_CORE             | Driver [QemuFwCfgAcpiPlatform] was discovered but
>> DXE_CORE             | not loaded!!
>> ...
>> RamDiskDxe           | RamDiskAcpiCheck: Cannot locate the EFI ACPI
>> RamDiskDxe           | Table Protocol, unable to publish RAM disks to
>> RamDiskDxe           | NFIT.
>
> (BootGraphicsResourceTableDxe's ReadyToBoot callback --
> InstallBootGraphicsResourceTable() -- handles the lack of
> EFI_ACPI_TABLE_PROTOCOL silently.) Later the guest kernel logs
>
>> [    0.000000] efi:  SMBIOS 3.0=0x13bdb0000  MEMATTR=0x138b3c018
>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Leif Lindholm <leif.lindholm@linaro.org>
> Ref: https://bugzilla.redhat.com/show_bug.cgi?id=1430262
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

> ---
>  ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf |  6 +--
>  ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c   | 45 ++++++++++++--------
>  2 files changed, 29 insertions(+), 22 deletions(-)
>
> diff --git a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf
> index 7724cf215dda..95a56a10bb5c 100644
> --- a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf
> +++ b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf
> @@ -28,11 +28,12 @@ [Packages]
>    ArmPkg/ArmPkg.dec
>    ArmVirtPkg/ArmVirtPkg.dec
>    MdePkg/MdePkg.dec
> +  OvmfPkg/OvmfPkg.dec
>
>  [LibraryClasses]
>    BaseLib
>    DebugLib
> -  PcdLib
> +  QemuFwCfgLib
>    UefiBootServicesTableLib
>    UefiDriverEntryPoint
>
> @@ -40,8 +41,5 @@ [Protocols]
>    gEdkiiPlatformHasAcpiProtocolGuid       ## SOMETIMES_PRODUCES
>    gEdkiiPlatformHasDeviceTreeProtocolGuid ## SOMETIMES_PRODUCES
>
> -[FeaturePcd]
> -  gArmVirtTokenSpaceGuid.PcdPureAcpiBoot ## CONSUMES
> -
>  [Depex]
>    TRUE
> diff --git a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c
> index 8681f813a6b5..46f96401632c 100644
> --- a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c
> +++ b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c
> @@ -15,7 +15,7 @@
>
>  #include <Library/BaseLib.h>
>  #include <Library/DebugLib.h>
> -#include <Library/PcdLib.h>
> +#include <Library/QemuFwCfgLib.h>
>  #include <Library/UefiBootServicesTableLib.h>
>  #include <Protocol/PlatformHasAcpi.h>
>  #include <Protocol/PlatformHasDeviceTree.h>
> @@ -27,18 +27,27 @@ PlatformHasAcpiDt (
>    IN EFI_SYSTEM_TABLE *SystemTable
>    )
>  {
> -  EFI_STATUS Status;
> -
> -  Status = EFI_SUCCESS;
> +  EFI_STATUS           Status;
> +  FIRMWARE_CONFIG_ITEM FwCfgItem;
> +  UINTN                FwCfgSize;
>
>    //
>    // If we fail to install any of the necessary protocols below, the OS will be
>    // unbootable anyway (due to lacking hardware description), so tolerate no
>    // errors here.
>    //
> -  // Always make ACPI available on 64-bit systems.
> -  //
> -  if (MAX_UINTN == MAX_UINT64) {
> +  if (MAX_UINTN == MAX_UINT64 &&
> +      !EFI_ERROR (
> +         QemuFwCfgFindFile (
> +           "etc/table-loader",
> +           &FwCfgItem,
> +           &FwCfgSize
> +           )
> +         )) {
> +    //
> +    // Only make ACPI available on 64-bit systems, and only if QEMU generates
> +    // (a subset of) the ACPI tables.
> +    //
>      Status = gBS->InstallProtocolInterface (
>                      &ImageHandle,
>                      &gEdkiiPlatformHasAcpiProtocolGuid,
> @@ -48,21 +57,21 @@ PlatformHasAcpiDt (
>      if (EFI_ERROR (Status)) {
>        goto Failed;
>      }
> +
> +    return Status;
>    }
>
>    //
> -  // Expose the Device Tree unless PcdPureAcpiBoot is set.
> +  // Expose the Device Tree otherwise.
>    //
> -  if (!FeaturePcdGet (PcdPureAcpiBoot)) {
> -    Status = gBS->InstallProtocolInterface (
> -                    &ImageHandle,
> -                    &gEdkiiPlatformHasDeviceTreeProtocolGuid,
> -                    EFI_NATIVE_INTERFACE,
> -                    NULL
> -                    );
> -    if (EFI_ERROR (Status)) {
> -      goto Failed;
> -    }
> +  Status = gBS->InstallProtocolInterface (
> +                  &ImageHandle,
> +                  &gEdkiiPlatformHasDeviceTreeProtocolGuid,
> +                  EFI_NATIVE_INTERFACE,
> +                  NULL
> +                  );
> +  if (EFI_ERROR (Status)) {
> +    goto Failed;
>    }
>
>    return Status;
> --
> 2.9.3
>
>