[Qemu-devel] [PATCH v15 4/6] pvpanic: add document of pvpanic

[Hu Tao]

Signed-off-by: Hu Tao <address@hidden>
---
 docs/specs/pvpanic.txt | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)
 create mode 100644 docs/specs/pvpanic.txt

diff --git a/docs/specs/pvpanic.txt b/docs/specs/pvpanic.txt
new file mode 100644
index 0000000..761d20c
--- /dev/null
+++ b/docs/specs/pvpanic.txt
@@ -0,0 +1,25 @@
+PVPANIC DEVICE
+==============
+
+pvpanic device is a simulated ISA device, through which guest panic
+event is sent to qemu, and a QMP event is generated. This allows
+management apps(e.g. libvirt) to be notified and respond to the
+event.
+
+pvpanic uses port 0x505 by default to receive panic event from guest.
+The port is configurable by specifying ioport property.
+
+pvpanic device is defined with ACPI ID "QEMU0001". To send panic
+event, guest evaluates method WRPT, specifying a byte, bit 0 set,
+as argument. Other bits are reserved.
+
+To use it, one will have to:
+
+1. add the device by specifying `-device pvpanic' in the qemu command
+   line.
+
+2. load pvpanic device driver in guest OS.
+
+The management app has the options of waiting for GUEST_PANICKED events,
+and/or polling for guest-panicked RunState, to learn when the pvpanic
+device has fired a panic event.
-- 
1.8.1.4