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 <[email protected]>
---
Notes:
changes in v4:
- reword commit message to warn against the (1.7.0, pc-i440fx-1.7) pair
more prominently [Jordan]
- replace Func with __FUNCTION__ in debug messages [Jordan]
- log table signature and length from the header probe only after
EFI_PROTOCOL_ERROR isn't possible for it any more (ie. after the
header passes all checks)
- recognize and accept trailing NULs in fw_cfg contents (therefore the
function can now return EFI_PROTOCOL_ERROR too, for non-NUL trailing
garbage) [Jordan]
OvmfPkg/AcpiPlatformDxe/AcpiPlatform.h | 7 +-
OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c | 12 ++-
OvmfPkg/AcpiPlatformDxe/Qemu.c | 153 +++++++++++++++++++++++++++++++++
3 files changed, 164 insertions(+), 8 deletions(-)
diff --git a/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.h
b/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.h
index 21107cd..c643fa1 100644
--- a/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.h
+++ b/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.h
@@ -10,7 +10,7 @@
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
-**/
+**/
#ifndef _ACPI_PLATFORM_H_INCLUDED_
#define _ACPI_PLATFORM_H_INCLUDED_
@@ -61,5 +61,10 @@ InstallXenTables (
IN EFI_ACPI_TABLE_PROTOCOL *AcpiProtocol
);
+EFI_STATUS
+EFIAPI
+InstallQemuLinkedTables (
+ IN EFI_ACPI_TABLE_PROTOCOL *AcpiProtocol
+ );
#endif
diff --git a/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c
b/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c
index 6e0b610..084c393 100644
--- a/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c
+++ b/OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c
@@ -256,16 +256,14 @@ AcpiPlatformEntryPoint (
if (XenDetected ()) {
Status = InstallXenTables (AcpiTable);
- if (EFI_ERROR (Status)) {
- Status = FindAcpiTablesInFv (AcpiTable);
- }
} else {
+ Status = InstallQemuLinkedTables (AcpiTable);
+ }
+
+ if (EFI_ERROR (Status)) {
Status = FindAcpiTablesInFv (AcpiTable);
}
- if (EFI_ERROR (Status)) {
- return Status;
- }
- return EFI_SUCCESS;
+ return Status;
}
diff --git a/OvmfPkg/AcpiPlatformDxe/Qemu.c b/OvmfPkg/AcpiPlatformDxe/Qemu.c
index 06bd463..e62467a 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;
+}
--
1.8.3.1
------------------------------------------------------------------------------
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