On 03/14/2012 12:46 PM, Gleb Natapov wrote: > On Wed, Mar 14, 2012 at 12:29:57PM +0200, Avi Kivity wrote: > > On 03/14/2012 12:26 PM, Wen Congyang wrote: > > > >> If so, is this channel visible to guest userspace? If the channle is visible to guest > > > >> userspace, the program running in userspace may write the same message to the channel. > > > >> > > > > > > > > Surely there's some kind of access control on channels. > > > > > > The virtio-serial depends on more things than touching the hypervisor. So I think touching > > > the hypervisor is more reliable than using virtio-serial device, and it is very simple and > > > easy to use. > > > > > > If we pass something from guest userspace to host, we can use virtio-serial. But If we pass > > > something from guest kernelspace to host, I still prefer to touch the hypervisor. > > > > There's no argument that it's easier. My concern is different, we're > > adding more and more stuff to the hypervisor because it's easier, which > > bloats it. Every time we do it we add to compatibility and security > > problems. > > > > The panic notification is *really* simple, so I don't expect it to cause > > a lot of problems. But still, if it's possible not to change the > > hypervisor, we must make an effort in that direction. > > > One more point against using virtio-serial is that it will be likely > compiled as a module which means panic during early boot will not be > reported. 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. -- error compiling committee.c: too many arguments to function -- 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
