OvmfPkg: AcpiPlatformDxe: download ACPI tables from QEMU

Recent qemu versions compose all ACPI tables on the host side, according
to the target hardware configuration, and make the tables available to any
guest firmware over fw_cfg.

See version compatibility information below.

The feature moves the burden of keeping ACPI tables up-to-date from boot
firmware to qemu (which is the source of hardware configuration anyway).

This patch adds client code for this feature. Benefits of the
qemu-provided ACPI tables include PCI hotplug for example.

Qemu provides the following three fw_cfg files:
- etc/acpi/rsdp
- etc/acpi/tables
- etc/table-loader

"etc/acpi/rsdp" and "etc/acpi/tables" are similar, they are only kept
separate because they have different allocation requirements in SeaBIOS.

Both of these fw_cfg files contain preformatted ACPI payload.
"etc/acpi/rsdp" contains only the RSDP table, while "etc/acpi/tables"
contains all other tables, concatenated.

The tables in these two fw_cfg files are filled in by qemu, but two kinds
of fields are left incomplete in each table: pointers to other tables, and
checksums (which depend on the pointers).

Qemu initializes each pointer with a relative offset into the fw_cfg file
that contains the pointed-to ACPI table. The final pointer values depend
on where the fw_cfg files, holding the pointed-to ACPI tables, will be
placed in memory by the guest. That is, the pointer fields need to be
"relocated" (incremented) by the base addresses of where "/etc/acpi/rsdp"
and "/etc/acpi/tables" will be placed in guest memory.

This is where the third file, "/etc/table-loader" comes in the picture. It
is a linker/loader script that has several command types:

  One command type instructs the guest to download the other two files.

  Another command type instructs the guest to increment ("absolutize") a
  pointer field (having a relative initial value) in the pointing ACPI
  table, present in some fw_cfg file, with the dynamic base address of the
  same (or another) fw_cfg file, holding the pointed-to ACPI table.

  The third command type instructs the guest to compute checksums over
  ranges and to store them.

In edk2, EFI_ACPI_TABLE_PROTOCOL knows about table relationships -- it
handles linkage automatically when a table is installed. The protocol
takes care of checksumming too. RSDP is installed automatically. Hence we
only need to care about the "etc/acpi/tables" fw_cfg file, determining the
boundaries of each ACPI table inside it, and installing those tables.

Qemu compatibility information:

--------------+---------------------+-------------------------------------
 qemu version | qemu machine type   | effects of the patch
--------------+---------------------+-------------------------------------
 up to 1.6.x  | any pc-i440fx       | None. OVMF's built-in ACPI tables
              |                     | are used.
--------------+---------------------+-------------------------------------
 any          | up to pc-i440fx-1.6 | None. OVMF's built-in ACPI tables
              |                     | are used.
--------------+---------------------+-------------------------------------
 1.7.0        | pc-i440fx-1.7       | Potential guest OS crash, dependent
              | (default for 1.7.0) | on guest RAM size.
              |                     |
              |                     | DO NOT RUN OVMF on the (1.7.0,
              |                     | pc-i440fx-1.7) qemu / machine type
              |                     | combination.
--------------+---------------------+-------------------------------------
 1.7.1        | pc-i440fx-1.7       | OVMF downloads valid ACPI tables
              | (default for 1.7.1) | from qemu and passes them to the
              |                     | guest OS.
--------------+---------------------+-------------------------------------
 2.0.0-rc0    | pc-i440fx-1.7 or    | OVMF downloads valid ACPI tables
              | later               | from qemu and passes them to the
              |                     | guest OS.
 -------------+---------------------+-------------------------------------

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@15420 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 153 insertions, 0 deletions

diff --git a/OvmfPkg/AcpiPlatformDxe/Qemu.c b/OvmfPkg/AcpiPlatformDxe/Qemu.c
index 06bd46370e..e62467a5bc 100644
--- a/OvmfPkg/AcpiPlatformDxe/Qemu.c
+++ b/OvmfPkg/AcpiPlatformDxe/Qemu.c
@@ -515,3 +515,156 @@ QemuInstallAcpiTable (
            );

 }

 

+

+/**

+  Download the ACPI table data file from QEMU and interpret it.

+

+  @param[in] AcpiProtocol  The ACPI table protocol used to install tables.

+

+  @retval  EFI_UNSUPPORTED       Firmware configuration is unavailable.

+

+  @retval  EFI_NOT_FOUND         The host doesn't export the required fw_cfg

+                                 files.

+

+  @retval  EFI_OUT_OF_RESOURCES  Memory allocation failed.

+

+  @retval  EFI_PROTOCOL_ERROR    Found truncated or invalid ACPI table header

+                                 in the fw_cfg contents.

+

+  @return                        Status codes returned by

+                                 AcpiProtocol->InstallAcpiTable().

+

+**/

+

+//

+// We'll be saving the keys of installed tables so that we can roll them back

+// in case of failure. 128 tables should be enough for anyone (TM).

+//

+#define INSTALLED_TABLES_MAX 128

+

+EFI_STATUS

+EFIAPI

+InstallQemuLinkedTables (

+  IN   EFI_ACPI_TABLE_PROTOCOL       *AcpiProtocol

+  )

+{

+  EFI_STATUS           Status;

+  FIRMWARE_CONFIG_ITEM TablesFile;

+  UINTN                TablesFileSize;

+  UINT8                *Tables;

+  UINTN                *InstalledKey;

+  UINTN                Processed;

+  INT32                Installed;

+

+  Status = QemuFwCfgFindFile ("etc/acpi/tables", &TablesFile, &TablesFileSize);

+  if (EFI_ERROR (Status)) {

+    DEBUG ((EFI_D_INFO, "%a: \"etc/acpi/tables\" interface unavailable: %r\n",

+      __FUNCTION__, Status));

+    return Status;

+  }

+

+  Tables = AllocatePool (TablesFileSize);

+  if (Tables == NULL) {

+    return EFI_OUT_OF_RESOURCES;

+  }

+

+  QemuFwCfgSelectItem (TablesFile);

+  QemuFwCfgReadBytes (TablesFileSize, Tables);

+

+  InstalledKey = AllocatePool (INSTALLED_TABLES_MAX * sizeof *InstalledKey);

+  if (InstalledKey == NULL) {

+    Status = EFI_OUT_OF_RESOURCES;

+    goto FreeTables;

+  }

+

+  Processed = 0;

+  Installed = 0;

+  while (Processed < TablesFileSize) {

+    UINTN                       Remaining;

+    EFI_ACPI_DESCRIPTION_HEADER *Probe;

+

+    Remaining = TablesFileSize - Processed;

+    if (Remaining < sizeof *Probe) {

+      Status = EFI_PROTOCOL_ERROR;

+      break;

+    }

+

+    Probe = (EFI_ACPI_DESCRIPTION_HEADER *) (Tables + Processed);

+    if (Remaining < Probe->Length || Probe->Length < sizeof *Probe) {

+      Status = EFI_PROTOCOL_ERROR;

+      break;

+    }

+

+    DEBUG ((EFI_D_VERBOSE, "%a: offset 0x%016Lx:"

+      " Signature=\"%-4.4a\" Length=0x%08x\n",

+      __FUNCTION__, (UINT64) Processed,

+      (CONST CHAR8 *) &Probe->Signature, Probe->Length));

+

+    //

+    // skip automatically handled "root" tables: RSDT, XSDT

+    //

+    if (Probe->Signature !=

+                        EFI_ACPI_1_0_ROOT_SYSTEM_DESCRIPTION_TABLE_SIGNATURE &&

+        Probe->Signature !=

+                    EFI_ACPI_2_0_EXTENDED_SYSTEM_DESCRIPTION_TABLE_SIGNATURE) {

+      if (Installed == INSTALLED_TABLES_MAX) {

+        DEBUG ((EFI_D_ERROR, "%a: can't install more than %d tables\n",

+          __FUNCTION__, INSTALLED_TABLES_MAX));

+        Status = EFI_OUT_OF_RESOURCES;

+        break;

+      }

+

+      Status = AcpiProtocol->InstallAcpiTable (AcpiProtocol, Probe,

+                 Probe->Length, &InstalledKey[Installed]);

+      if (EFI_ERROR (Status)) {

+        DEBUG ((EFI_D_ERROR,

+          "%a: failed to install table \"%-4.4a\" at offset 0x%Lx: %r\n",

+          __FUNCTION__, (CONST CHAR8 *) &Probe->Signature, (UINT64) Processed,

+          Status));

+        break;

+      }

+

+      ++Installed;

+    }

+

+    Processed += Probe->Length;

+  }

+

+  //

+  // NUL-padding at the end is accepted

+  //

+  if (Status == EFI_PROTOCOL_ERROR) {

+    UINTN ErrorLocation;

+

+    ErrorLocation = Processed;

+    while (Processed < TablesFileSize && Tables[Processed] == '\0') {

+      ++Processed;

+    }

+    if (Processed < TablesFileSize) {

+      DEBUG ((EFI_D_ERROR, "%a: truncated or invalid ACPI table header at "

+        "offset 0x%Lx\n", __FUNCTION__, (UINT64) ErrorLocation));

+    }

+  }

+

+  if (Processed == TablesFileSize) {

+    DEBUG ((EFI_D_INFO, "%a: installed %d tables\n", __FUNCTION__, Installed));

+    Status = EFI_SUCCESS;

+  } else {

+    ASSERT (EFI_ERROR (Status));

+

+    //

+    // Roll back partial installation.

+    //

+    while (Installed > 0) {

+      --Installed;

+      AcpiProtocol->UninstallAcpiTable (AcpiProtocol, InstalledKey[Installed]);

+    }

+  }

+

+  FreePool (InstalledKey);

+

+FreeTables:

+  FreePool (Tables);

+

+  return Status;

+}