On 09/18/09 19:55, Anthony Liguori wrote: >> So you need break, parity ... no be serious please > > Sure, why not? > > In QEMU, we have the ability to hook our devices directly to a physical > serial device and we pass through break, parity, and the other serial > device properties. Yes for a emulated 16550. No for virtio-console. If you want the guest drive some silly piece of hardware which wants a serial mode != 8N1 or needs breaks you can't use virtio-console. > Again, this is paravirtual serial device and I think it's entirely > reasonable for people to hook up these ports in the guest directly to > physical serial devices in the host. Except that the paravirtual device named 'virtio-console' simply doesn't allow to set serial parameters such as parity, data bits and stop bits. It is *really* just a (single) byte stream piped over a virtio ring. The guest side happens to be connected to hvc, so you can use that as console, thus the name 'virtio-console'. The plan is to extend that to multiple byte streams. The streams can be hooked up to hvc (and one stream allways will be for backward compatibility reasons), giving you a text console. Or they can be linked to a character device with a name tag (aka sysfs attribute), providing a named bidirectional byte stream for guest<->host communication. > From my perspective, this is a paravirtual serial device and nothing > more. It simply isn't, see above. > All the discussion of things like guest copy/paste support is a > bit silly. Implementing transparent copy/paste support needs some communication channel between guest and host. The multiport virtio console driver provides just that. > This is the wrong way to approach that sort of thing because > it's not something that belongs in the kernel at all. Who claimed the copy/paste bits should go into the kernel? They will not of course. > Furthermore, the > current proposal doesn't handle anything like save/restore which is > needed for live migration. That is something the host side (i.e. qemu) has to solve. The guest will not care about it at all ;) cheers, Gerd _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/virtualization
