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Diffstat (limited to 'docs/specs/fw_cfg.txt')
| -rw-r--r-- | docs/specs/fw_cfg.txt | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/docs/specs/fw_cfg.txt b/docs/specs/fw_cfg.txt index 536909a4b2..b8c794f546 100644 --- a/docs/specs/fw_cfg.txt +++ b/docs/specs/fw_cfg.txt @@ -93,6 +93,9 @@ by selecting the "signature" item using key 0x0000 (FW_CFG_SIGNATURE), and reading four bytes from the data register. If the fw_cfg device is present, the four bytes read will contain the characters "QEMU". +If the DMA interface is available, then reading the DMA Address +Register returns 0x51454d5520434647 ("QEMU CFG" in big-endian format). + === Revision / feature bitmap (Key 0x0001, FW_CFG_ID) === A 32-bit little-endian unsigned int, this item is used to check for enabled |