pvpanic.txt (1874B)
1 PVPANIC DEVICE 2 ============== 3 4 pvpanic device is a simulated device, through which a guest panic 5 event is sent to qemu, and a QMP event is generated. This allows 6 management apps (e.g. libvirt) to be notified and respond to the event. 7 8 The management app has the option of waiting for GUEST_PANICKED events, 9 and/or polling for guest-panicked RunState, to learn when the pvpanic 10 device has fired a panic event. 11 12 The pvpanic device can be implemented as an ISA device (using IOPORT) or as a 13 PCI device. 14 15 ISA Interface 16 ------------- 17 18 pvpanic exposes a single I/O port, by default 0x505. On read, the bits 19 recognized by the device are set. Software should ignore bits it doesn't 20 recognize. On write, the bits not recognized by the device are ignored. 21 Software should set only bits both itself and the device recognize. 22 23 Bit Definition 24 -------------- 25 bit 0: a guest panic has happened and should be processed by the host 26 bit 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 30 PCI Interface 31 ------------- 32 33 The PCI interface is similar to the ISA interface except that it uses an MMIO 34 address space provided by its BAR0, 1 byte long. Any machine with a PCI bus 35 can enable a pvpanic device by adding '-device pvpanic-pci' to the command 36 line. 37 38 ACPI Interface 39 -------------- 40 41 pvpanic device is defined with ACPI ID "QEMU0001". Custom methods: 42 43 RDPT: To determine whether guest panic notification is supported. 44 Arguments: None 45 Return: Returns a byte, with the same semantics as the I/O port 46 interface. 47 48 WRPT: To send a guest panic event 49 Arguments: Arg0 is a byte to be written, with the same semantics as 50 the I/O interface. 51 Return: None 52 53 The ACPI device will automatically refer to the right port in case it 54 is modified.