On Sun, Dec 14, 2008 at 02:28:23PM +0200, Blue Swirl wrote:
On 12/14/08, Gleb Natapov <address@hidden> wrote:
There is a need for communication channel between host and various
agents that are running inside a VM guest. The channel will be used
for statistic gathering, logging, cut & paste, host screen resolution
changes notification, guest configuration etc.
Isn't this exactly what the firmware configuration device was supposed
to be used for? In the list of use cases you gave, I don't see
anything that could not be done with it.
The requirement for firmware configuration interface was different. We
wanted something simple that we can use as early as possible in cpu init
code and performance was not considered at all. Obviously PCI device doesn't
fit for this. We don't want to write PCI driver inside a BIOS and PCI
initialization is too late in HW initialization sequence.
The requirement for vmchannel was that it should allow a guest
to communicate with external (to qemu) process and with reasonable
performance too.