From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: Re: [PATCH v7.5] kvm: notify host when the guest is panicked Date: Sun, 22 Jul 2012 13:39:57 +0200 Message-ID: <500BE68D.90005@gmail.com> References: <500A565A.8080403@cn.fujitsu.com> <500A6BF1.4030002@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , kvm list , Jan Kiszka , qemu-devel , "linux-kernel@vger.kernel.org" , Avi Kivity , KAMEZAWA Hiroyuki To: Wen Congyang Return-path: In-Reply-To: <500A6BF1.4030002@cn.fujitsu.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org List-Id: kvm.vger.kernel.org On 07/21/2012 10:44 AM, Wen Congyang wrote: > 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 kernel Was the option of implementing a virtio-watchdog driver considered? You're basically re-implementing a watchdog, a guest-host interface and a set of protocols for guest-host communications. Why can't we re-use everything we have now, push a virtio watchdog driver into drivers/watchdog/, and gain a more complete solution to detecting hangs inside the guest.