Qemu v1.7.0 features an ACPI linker/loader interface, available over
fw_cfg, written by Michael Tsirkin.
Qemu composes all ACPI tables on the host side, according to the target
hardware configuration, and makes the tables available to any guest
firmware over fw_cfg.
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 files for 1.7+ machine types:
- 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.
Compatibility information:
- The patch has no effect when OVMF runs on qemu versions up to v1.6.x.
OVMF's built-in ACPI tables are used.
- The patch has no effect when OVMF runs on any qemu version, and a
machine type up to "pc-i440fx-1.6" is selected. OVMF's built-in ACPI
tables are used.
- The patch causes a regression in PCI resource allocation for some guest
RAM sizes (eg. 2560MB) when OVMF runs on qemu v1.7.0 precisely, and the
"pc-i440fx-1.7" (ie. default) machine type is selected. This bug has
been fixed in qemu v1.7.1 (commit 03bc4f6 -- "piix: fix 32bit pci
hole").
- The patch has the intended effect when OVMF runs on qemu versions
v1.7.1+ (including the current development tree, v2.0.0-rc0) and a
pc-i440fx-1.7+ machine type is selected.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Laszlo Ersek <[email protected]>
---
Notes:
v1: http://thread.gmane.org/gmane.comp.bios.tianocore.devel/4881
v2: http://thread.gmane.org/gmane.comp.bios.tianocore.devel/5103
v3: this posting
v1->v2 changes:
- move large comment block from "OvmfPkg/AcpiPlatformDxe/Qemu.c" to
commit message
- fall back to builtin tables if 32-bit PCI window has not been found in
the PEI phase (and consequently could not cause PCI resource
allocation to match qemu's ACPI tables)
- trim excessive logging
v2->v3:
- Support for the "etc/pci-info" fw_cfg file has been revoked in qemu
v1.7.0 (hence there is no official qemu release that provdies it). The
bottom of the 32-bit PCI hole that is exported in qemu's DSDT/SSDTs
has been fixed in qemu v1.7.1 (qemu commit 03bc4f6), thus we don't
need "etc/pci-info" any longer.
Testing: been running my Linux and Windows guests with this patch for
months.
OvmfPkg/AcpiPlatformDxe/AcpiPlatform.h | 7 +-
OvmfPkg/AcpiPlatformDxe/AcpiPlatform.c | 12 ++-
OvmfPkg/AcpiPlatformDxe/Qemu.c | 138 +++++++++++++++++++++++++++++++++
3 files changed, 149 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..91f6db5 100644
--- a/OvmfPkg/AcpiPlatformDxe/Qemu.c
+++ b/OvmfPkg/AcpiPlatformDxe/Qemu.c
@@ -515,3 +515,141 @@ 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.
+
+ @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
+ )
+{
+ STATIC CONST CHAR8 Func[] = "InstallQemuLinkedTables";
+ 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",
+ Func, 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) {
+ DEBUG ((EFI_D_VERBOSE, "%a: truncated ACPI table header at offset "
+ "0x%Lx\n", Func, (UINT64) Processed));
+ Status = EFI_PROTOCOL_ERROR;
+ break;
+ }
+
+ Probe = (EFI_ACPI_DESCRIPTION_HEADER *) (Tables + Processed);
+ DEBUG ((EFI_D_VERBOSE, "%a: offset 0x%016Lx:"
+ " Signature=\"%-4.4a\" Length=0x%08x\n",
+ Func, (UINT64) Processed,
+ (CONST CHAR8 *) &Probe->Signature, Probe->Length));
+
+ if (Remaining < Probe->Length || Probe->Length < sizeof *Probe) {
+ DEBUG ((EFI_D_VERBOSE, "%a: invalid ACPI table header at offset 0x%Lx\n",
+ Func, (UINT64) Processed));
+ Status = EFI_PROTOCOL_ERROR;
+ break;
+ }
+
+ //
+ // 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", Func,
+ 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", Func,
+ (CONST CHAR8 *) &Probe->Signature, (UINT64) Processed, Status));
+ break;
+ }
+
+ ++Installed;
+ }
+
+ Processed += Probe->Length;
+ }
+
+ if (Processed == TablesFileSize || Status == EFI_PROTOCOL_ERROR) {
+ DEBUG ((EFI_D_INFO, "%a: installed %d tables\n", Func, 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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