mirror of https://github.com/acidanthera/audk.git
96bbdbc856
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
|
||
|---|---|---|
| .. | ||
| AcpiPlatform.c | ||
| AcpiPlatform.h | ||
| AcpiPlatformDxe.inf | ||
| Qemu.c | ||
| Xen.c | ||