1PVPANIC DEVICE 2============== 3 4pvpanic device is a simulated device, through which a guest panic 5event is sent to qemu, and a QMP event is generated. This allows 6management apps (e.g. libvirt) to be notified and respond to the event. 7 8The management app has the option of waiting for GUEST_PANICKED events, 9and/or polling for guest-panicked RunState, to learn when the pvpanic 10device has fired a panic event. 11 12The pvpanic device can be implemented as an ISA device (using IOPORT) or as a 13PCI device. 14 15ISA Interface 16------------- 17 18pvpanic exposes a single I/O port, by default 0x505. On read, the bits 19recognized by the device are set. Software should ignore bits it doesn't 20recognize. On write, the bits not recognized by the device are ignored. 21Software should set only bits both itself and the device recognize. 22 23Bit Definition 24~~~~~~~~~~~~~~ 25 26bit 0 27 a guest panic has happened and should be processed by the host 28bit 1 29 a guest panic has happened and will be handled by the guest; 30 the host should record it or report it, but should not affect 31 the execution of the guest. 32bit 2 (to be implemented) 33 a regular guest shutdown has happened and should be processed by the host 34 35PCI Interface 36------------- 37 38The PCI interface is similar to the ISA interface except that it uses an MMIO 39address space provided by its BAR0, 1 byte long. Any machine with a PCI bus 40can enable a pvpanic device by adding ``-device pvpanic-pci`` to the command 41line. 42 43ACPI Interface 44-------------- 45 46pvpanic device is defined with ACPI ID "QEMU0001". Custom methods: 47 48RDPT 49~~~~ 50 51To determine whether guest panic notification is supported. 52 53Arguments 54 None 55Return 56 Returns a byte, with the same semantics as the I/O port interface. 57 58WRPT 59~~~~ 60 61To send a guest panic event. 62 63Arguments 64 Arg0 is a byte to be written, with the same semantics as the I/O interface. 65Return 66 None 67 68The ACPI device will automatically refer to the right port in case it 69is modified. 70