diff options
| author | Kevin O'Connor <kevin@koconnor.net> | 2015-10-08 17:02:58 +0200 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2015-10-19 15:26:54 +0200 |
| commit | 2cc06a8843ace3d03464032eb3c74bc6e2b07579 (patch) | |
| tree | a26f32b3b9cdf3aaf3080e61c561be64ee26bf4d /docs | |
| parent | c886fc4c20ff8456b2f788a1404dd321b8b59243 (diff) | |
fw_cfg: Define a static signature to be returned on DMA port reads
Return a static signature ("QEMU CFG") if the guest does a read to the
DMA address io register.
Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Diffstat (limited to 'docs')
| -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 |