OvmfPkg: AcpiPlatformDxe: don't rely on unstable QEMU interface

The fw_cfg file "etc/acpi/tables" is not a stable guest interface -- QEMU
could rename it in the future, and/or introduce additional fw_cfg files
with ACPI payload. Only the higher-level "etc/table-loader" file is
considered stable, which contains a sequence of commands to assist
firmware with reading QEMU ACPI tables from the FwCfg interface.

Because edk2 provides publishing support for ACPI tables, OVMF only uses
the Allocate command to find the names of FwCfg files to read and publish
as ACPI tables.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Jordan Justen <jordan.l.justen@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15574 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 49 insertions, 5 deletions

diff --git a/OvmfPkg/AcpiPlatformDxe/Qemu.c b/OvmfPkg/AcpiPlatformDxe/Qemu.c
index 5a96d76a1f..70f3ff6426 100644
--- a/OvmfPkg/AcpiPlatformDxe/Qemu.c
+++ b/OvmfPkg/AcpiPlatformDxe/Qemu.c
@@ -16,6 +16,7 @@
 **/

 

 #include "AcpiPlatform.h"

+#include "QemuLoader.h"

 #include <Library/BaseMemoryLib.h>

 #include <Library/MemoryAllocationLib.h>

 #include <Library/QemuFwCfgLib.h>

@@ -795,8 +796,7 @@ InstallQemuLinkedTables (
   @retval  EFI_OUT_OF_RESOURCES  Memory allocation failed, or more than

                                  INSTALLED_TABLES_MAX tables found.

 

-  @retval  EFI_PROTOCOL_ERROR    Found truncated or invalid ACPI table header

-                                 in the fw_cfg contents.

+  @retval  EFI_PROTOCOL_ERROR    Found invalid fw_cfg contents.

 

   @return                        Status codes returned by

                                  AcpiProtocol->InstallAcpiTable().

@@ -812,6 +812,10 @@ InstallAllQemuLinkedTables (
   UINTN                *InstalledKey;

   INT32                Installed;

   EFI_STATUS           Status;

+  FIRMWARE_CONFIG_ITEM LoaderItem;

+  UINTN                LoaderSize;

+  UINT8                *Loader;

+  QEMU_LOADER_ENTRY    *Entry, *End;

 

   InstalledKey = AllocatePool (INSTALLED_TABLES_MAX * sizeof *InstalledKey);

   if (InstalledKey == NULL) {

@@ -819,10 +823,49 @@ InstallAllQemuLinkedTables (
   }

   Installed = 0;

 

-  Status = InstallQemuLinkedTables ("etc/acpi/tables", AcpiProtocol,

-             InstalledKey, &Installed);

+  Status = QemuFwCfgFindFile ("etc/table-loader", &LoaderItem, &LoaderSize);

+  if (EFI_ERROR (Status)) {

+    goto FreeInstalledKey;

+  }

+  if (LoaderSize % sizeof *Entry != 0) {

+    Status = EFI_PROTOCOL_ERROR;

+    goto FreeInstalledKey;

+  }

+

+  Loader = AllocatePool (LoaderSize);

+  if (Loader == NULL) {

+    Status = EFI_OUT_OF_RESOURCES;

+    goto FreeInstalledKey;

+  }

+

+  QemuFwCfgSelectItem (LoaderItem);

+  QemuFwCfgReadBytes (LoaderSize, Loader);

+

+  Entry = (QEMU_LOADER_ENTRY *)Loader;

+  End   = (QEMU_LOADER_ENTRY *)(Loader + LoaderSize);

+  while (Entry < End) {

+    if (Entry->Type == QemuLoaderCmdAllocate) {

+      QEMU_LOADER_ALLOCATE *Allocate;

+

+      Allocate = &Entry->Command.Allocate;

+      if (Allocate->File[sizeof Allocate->File - 1] != '\0') {

+        Status = EFI_PROTOCOL_ERROR;

+        break;

+      }

+

+      Status = InstallQemuLinkedTables ((CHAR8 *)Allocate->File, AcpiProtocol,

+                 InstalledKey, &Installed);

+      if (EFI_ERROR (Status)) {

+        ASSERT (Status != EFI_INVALID_PARAMETER);

+        break;

+      }

+    }

+    ++Entry;

+  }

+

+  FreePool (Loader);

+

   if (EFI_ERROR (Status)) {

-    ASSERT (Status != EFI_INVALID_PARAMETER);

     //

     // Roll back partial installation.

     //

@@ -834,6 +877,7 @@ InstallAllQemuLinkedTables (
     DEBUG ((EFI_D_INFO, "%a: installed %d tables\n", __FUNCTION__, Installed));

   }

 

+FreeInstalledKey:

   FreePool (InstalledKey);

   return Status;

 }