On Wed, Mar 14, 2012 at 03:16:05PM +0200, Avi Kivity wrote: > On 03/14/2012 03:14 PM, Gleb Natapov wrote: > > On Wed, Mar 14, 2012 at 03:07:46PM +0200, Avi Kivity wrote: > > > On 03/14/2012 01:11 PM, Wen Congyang wrote: > > > > > > > > > > I don't think we want to use the driver. Instead, have a small piece of > > > > > code that resets the device and pushes out a string (the panic message?) > > > > > without any interrupts etc. > > > > > > > > > > It's still going to be less reliable than a hypercall, I agree. > > > > > > > > Do you still want to use complicated and less reliable way? > > > > > > Are you willing to try it out and see how complicated it really is? > > > > > > While it's more complicated, it's also more flexible. You can > > > communicate the panic message, whether the guest is attempting a kdump > > > and its own recovery or whether it wants the host to do it, etc., you > > > can communicate less severe failures like oopses. > > > > > hypercall can take arguments to achieve the same. > > It has to be designed in advance; and every time we notice something's > missing we have to update the host kernel. > We and in the designed stage now. Not to late to design something flexible :) Panic hypercall can take GPA of a buffer where host puts panic info as a parameter. This buffer can be read by QEMU and passed to management. > > > > I think the other ones prefer to touch the hypervisor. > > > > > > I understand the sentiment. Your patches are simple and easy. But my > > > feeling is that the kernel has become too complicated already and I'm > > > looking for ways to limit changes. > > > > > Using virtio-serial will not reduce kernel complexity. Quite contrary > > since code that will use virtio-serial will be more complicated. > > The host kernel is unmodified though. > Yes, this is trade-off between complexity in hypervisor and a guest kernel. But in the end we use the same kernel for both. -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
