ArmVirtPkg/PlatformHasAcpiDtDxe: don't expose DT if QEMU provides ACPI

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: [EdkiiPlatformHasAcpi] 0

plus the usual messages. Later the guest kernel logs

> [    0.000000] efi:  SMBIOS 3.0=0x13bdb0000  ACPI 2.0=0x138440000
>                      MEMATTR=0x13a675018

before it lists the ACPI tables one by one.

In addition, in the guest, the "/sys/firmware/devicetree/*" shell pattern
matches no files, while the "/sys/firmware/acpi/tables/*" pattern matches
the ACPI tables.

* With "-no-acpi", the firmware logs:

> PlatformHasAcpiDtDxe | Found FwCfg @ 0x9020008/0x9020000
> PlatformHasAcpiDtDxe | Found FwCfg DMA @ 0x9020010
> PlatformHasAcpiDtDxe | InstallProtocolInterface:
> PlatformHasAcpiDtDxe | [EdkiiPlatformHasDeviceTree] 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=0x138caa018

In addition, in the guest, the "/sys/firmware/devicetree/*" shell pattern
matches the directory "/sys/firmware/devicetree/base", which contains a
large number of DT nodes, while the "/sys/firmware/acpi/tables/*" pattern
matches no files.

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>

2 files changed, 29 insertions, 23 deletions

diff --git a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c
index a718ce1b5a..8932dacabe 100644
--- a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c
+++ b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.c
@@ -17,7 +17,7 @@
 #include <Guid/PlatformHasDeviceTree.h>

 #include <Library/BaseLib.h>

 #include <Library/DebugLib.h>

-#include <Library/PcdLib.h>

+#include <Library/QemuFwCfgLib.h>

 #include <Library/UefiBootServicesTableLib.h>

 

 EFI_STATUS

@@ -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,

                     &gEdkiiPlatformHasAcpiGuid,

@@ -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,

-                    &gEdkiiPlatformHasDeviceTreeGuid,

-                    EFI_NATIVE_INTERFACE,

-                    NULL

-                    );

-    if (EFI_ERROR (Status)) {

-      goto Failed;

-    }

+  Status = gBS->InstallProtocolInterface (

+                  &ImageHandle,

+                  &gEdkiiPlatformHasDeviceTreeGuid,

+                  EFI_NATIVE_INTERFACE,

+                  NULL

+                  );

+  if (EFI_ERROR (Status)) {

+    goto Failed;

   }

 

   return Status;

diff --git a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf
index 2450500b3f..4466bead57 100644
--- a/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf
+++ b/ArmVirtPkg/PlatformHasAcpiDtDxe/PlatformHasAcpiDtDxe.inf
@@ -25,14 +25,14 @@
   PlatformHasAcpiDtDxe.c

 

 [Packages]

-  ArmVirtPkg/ArmVirtPkg.dec

   EmbeddedPkg/EmbeddedPkg.dec

   MdePkg/MdePkg.dec

+  OvmfPkg/OvmfPkg.dec

 

 [LibraryClasses]

   BaseLib

   DebugLib

-  PcdLib

+  QemuFwCfgLib

   UefiBootServicesTableLib

   UefiDriverEntryPoint

 

@@ -40,8 +40,5 @@
   gEdkiiPlatformHasAcpiGuid       ## SOMETIMES_PRODUCES ## PROTOCOL

   gEdkiiPlatformHasDeviceTreeGuid ## SOMETIMES_PRODUCES ## PROTOCOL

 

-[FeaturePcd]

-  gArmVirtTokenSpaceGuid.PcdPureAcpiBoot ## CONSUMES

-

 [Depex]

   TRUE