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-------------- 25bit 0: a guest panic has happened and should be processed by the host 26bit 1: a guest panic has happened and will be handled by the guest; 27 the host should record it or report it, but should not affect 28 the execution of the guest. 29 30PCI Interface 31------------- 32 33The PCI interface is similar to the ISA interface except that it uses an MMIO 34address space provided by its BAR0, 1 byte long. Any machine with a PCI bus 35can enable a pvpanic device by adding '-device pvpanic-pci' to the command 36line. 37 38ACPI Interface 39-------------- 40 41pvpanic device is defined with ACPI ID "QEMU0001". Custom methods: 42 43RDPT: To determine whether guest panic notification is supported. 44Arguments: None 45Return: Returns a byte, with the same semantics as the I/O port 46 interface. 47 48WRPT: To send a guest panic event 49Arguments: Arg0 is a byte to be written, with the same semantics as 50 the I/O interface. 51Return: None 52 53The ACPI device will automatically refer to the right port in case it 54is modified. 55