Closes the v4.2 plan's 'Driver-level Driver::on_error IPC' item.
Three pieces, layered:
1. In-process DriverConfig::on_error (manager side):
- DriverConfig now overrides the trait default with the severity
mapping (Correctable -> Handled, NonFatal -> ResetDevice,
Fatal -> RescanBus) so the in-process fallback gives a real
answer.
- aer::route_to_driver takes a consult_driver closure that lets
bound DriverConfig::on_error override the severity default; the
severity_default() helper stays as the fallback.
2. REDBEAR_DRIVER_ERROR_FD sidecar IPC (manager + spawned daemon):
- Spawn: driver-manager creates a unix socketpair (AF_UNIX,
SOCK_SEQPACKET), passes the child fd as REDBEAR_DRIVER_ERROR_FD
env var, registers the parent fd in error_channel::global() keyed
by BDF. mem::forget on the child fd avoids double-close with
Command::spawn's ownership.
- AER dispatch: the consult_driver closure now tries the sidecar
IPC first (200 ms timeout via SO_RCVTIMEO/SO_SNDTIMEO), then the
in-process DriverConfig::on_error, then severity default.
- Reap: error_channel::global().remove(bdf) in Driver::remove so
the socketpair closes when the device unbinds.
3. linux-kpi C-callable opt-in (driver side):
- New c_headers/linux/pci.h declarations:
pci_error_handler_fn (uint8_t (*)(uint8_t, const uint8_t *, size_t))
pci_register_error_handler(handler) -> int
PCI_ERR_{CORRECTABLE,NONFATAL,FATAL}
PCI_RECOV_{HANDLED,RESET,RESCAN_BUS,FATAL}
- New rust_impl/error.rs module:
* duplicated wire types (DriverErrorReport / DriverErrorResponse
with encode/decode) -- linux-kpi stays self-contained
* worker_loop() thread that reads length-prefixed requests,
invokes the registered C handler, writes length-prefixed
RecoveryAction responses
* pci_register_error_handler() reads REDBEAR_DRIVER_ERROR_FD,
spawns the worker thread, returns 0/1
Protocol (length-prefixed, little-endian):
manager -> driver: [u32 len][severity:u8][bdf_len:u8][bdf][raw_len:u32][raw]
driver -> manager: [u32 len][action:u8]
Tests:
driver-manager: 70 passed (was 65; +5 from error_channel + aer)
linux-kpi: cargo check clean (host test link fails on
redox_strerror_v1, pre-existing)
vasilito
3425f55c44