docs/designs/bios-bmc-smm-error-logging.md

1 # BIOS->BMC SMM Error Logging Queue Daemon
15 We've identified use cases where the BIOS will go into System Management Mode
19 implement a circular buffer over a shared BIOS->BMC buffer that the BIOS can
24 There are various ways of communicating between the BMC and the BIOS, but there
38 1. The BMC shall initialize the shared buffer in a way that the BIOS can
40 2. After initialization, the BIOS shall not have to wait for an ack back from
42 3. The BIOS shall be the main writer to the shared buffer, with the BMC mainly
45 5. The BIOS must be able to write a payload (~1KB) to the buffer within 50µs
68 … bytes                          | 0x0         | BMC at init  | Allows the BIOS to determine if it …
69 …BIOS Interface Version              | 4 bytes                          | 0x4         | BIOS at ini…
70 …be used. Must be checked by BIOS before logging. BMC can change this number when it suspects data …
73 …BIOS know BMC has seen the overflow incident. Toggled when BMC acks the overflow incident<br>**BIT…
74 …                         | 0x21        | BMC          | Used to allow the BIOS to detect when the …
76 …BIOS flags                          | 4 bytes                          | 0x28        | BIOS       …
77 …BIOS write pointer                  | 3 bytes                          | 0x2c        | BIOS       …
79 | Uncorrectable Error reserved region | TBD1                             | 0x30        | BIOS      …
80 | Error Logs from BIOS                | Size of the Buffer - 0x30 - TBD1 | 0x30 + TBD1 | BIOS      …
86 `Magic Number`. Once the `Magic Number` is written to, the BIOS will assume that
90 If there are any further initialization between the BIOS and the BMC required,
92 initialization completes. If the BIOS does not see the flag being set, the BIOS
129     with expertise both from the BMC and the BIOS side (which we currently lack)
141 - bios-bmc-smm-error-logger