Re: [PATCH v8] kvm: notify host when the guest is panicked
From: Marcelo Tosatti <hidden>
Date: 2012-08-14 15:48:35
Also in:
lkml, qemu-devel
On Tue, Aug 14, 2012 at 05:55:54PM +0300, Yan Vugenfirer wrote:
On Aug 14, 2012, at 1:42 PM, Jan Kiszka wrote:quoted
On 2012-08-14 10:56, Daniel P. Berrange wrote:quoted
On Mon, Aug 13, 2012 at 03:21:32PM -0300, Marcelo Tosatti wrote:quoted
On Wed, Aug 08, 2012 at 10:43:01AM +0800, Wen Congyang wrote:quoted
We can know the guest is panicked when the guest runs on xen. But we do not have such feature on kvm. Another purpose of this feature is: management app(for example: libvirt) can do auto dump when the guest is panicked. If management app does not do auto dump, the guest's user can do dump by hand if he sees the guest is panicked. We have three solutions to implement this feature: 1. use vmcall 2. use I/O port 3. use virtio-serial. We have decided to avoid touching hypervisor. The reason why I choose choose the I/O port is: 1. it is easier to implememt 2. it does not depend any virtual device 3. it can work when starting the kernelHow about searching for the "Kernel panic - not syncing" string in the guests serial output? Say libvirtd could take an action upon that?No, this is not satisfactory. It depends on the guest OS being configured to use the serial port for console output which we cannot mandate, since it may well be required for other purposes.Please don't forget Windows guests, there is no console and no "Kernel Panic" string ;) What I used for debugging purposes on Windows guest is to register a bugcheck callback in virtio-net driver and write 1 to VIRTIO_PCI_ISR register. Yan.
Considering whether a "panic-device" should cover other OSes is also something to consider. Even for Linux, is "panic" the only case which should be reported via the mechanism? What about oopses without panic? Is the mechanism general enough for supporting new events, etc.
quoted
Well, we have more than a single serial port, even when leaving virtio-serial aside... Jan -- Siemens AG, Corporate Technology, CT RTC ITP SDP-DE Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html