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. 32 33PCI Interface 34------------- 35 36The PCI interface is similar to the ISA interface except that it uses an MMIO 37address space provided by its BAR0, 1 byte long. Any machine with a PCI bus 38can enable a pvpanic device by adding ``-device pvpanic-pci`` to the command 39line. 40 41ACPI Interface 42-------------- 43 44pvpanic device is defined with ACPI ID "QEMU0001". Custom methods: 45 46RDPT 47~~~~ 48 49To determine whether guest panic notification is supported. 50 51Arguments 52 None 53Return 54 Returns a byte, with the same semantics as the I/O port interface. 55 56WRPT 57~~~~ 58 59To send a guest panic event. 60 61Arguments 62 Arg0 is a byte to be written, with the same semantics as the I/O interface. 63Return 64 None 65 66The ACPI device will automatically refer to the right port in case it 67is modified. 68