@@ -77,6 +77,15 @@ increasing address order, similar to memcpy().
Selector Register IOport: 0x510
Data Register IOport: 0x511
+== ACPI Interface ==
+
+The fw_cfg device is defined with ACPI ID "QEMU0002". Since we expect
+ACPI tables to be passed into the guest through the fw_cfg device itself,
+the guest-side BIOS can not use ACPI to find fw_cfg. However, once the
+bios is finished setting up ACPI tables and hands control over to the
+guest kernel, the latter can use the fw_cfg ACPI node for a more accurate
+inventory of in-use IOport or MMIO regions.
+
== Firmware Configuration Items ==
=== Signature (Key 0x0000, FW_CFG_SIGNATURE) ===
Signed-off-by: Gabriel Somlo <somlo@cmu.edu> --- docs/specs/fw_cfg.txt | 9 +++++++++ 1 file changed, 9 insertions(+)