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

[Laszlo Ersek <lersek@redhat.com>]

On 03/17/17 22:10, Ard Biesheuvel wrote:
> 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
> 
> Why is there no MEMATTR table in this case? Or was it omitted for brevity?

I don't have the slightest clue. What is the MEMATTR table?

... Hm, grepping the kernel, it's apparently the memory attributes
table. You added it in the following kernel commit:

a604af075a32 ("efi: Add support for the EFI_MEMORY_ATTRIBUTES_TABLE
config table", 2016-04-25)

and it is part of release v4.7.

Ah, I understand now. I used two kernels (two guests) for testing this,
namely "4.7.7-200.fc24.aarch64" and "4.5.0-15.el7.aarch64".

And, from the logs I collected, the "-no-acpi" log belongs to the Fedora
kernel, which has your MEMATTR patch; while the log without "-no-acpi"
(above) belongs to the RHEL-7.3 kernel, which does *not* have your
MEMATTR patch.

I've now removed "-no-acpi" from the Fedora 24 guest's config, and
repeated the test. It prints:

[    0.000000] efi:  SMBIOS 3.0=0x13bdb0000  ACPI 2.0=0x138440000
MEMATTR=0x13a689018

If you wish (and I don't have to submit a v3 for any other reason), I
can refresh the above line in the commit message.

Thanks!
Laszlo

> 
>>
>> 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>
>> ---
>>  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
>>
>>