Gregory Haskins wrote:
Avi Kivity wrote:
Gregory Haskins wrote:
virtio is already non-kvm-specific (lguest uses it) and
non-pci-specific (s390 uses it).
Ok, then to be more specific, I need it to be more generic than it
already is. For instance, I need it to be able to integrate with
shm_signals.
Why?
Well, shm_signals is what I designed to be the event mechanism for vbus
devices. One of the design criteria of shm_signal is that it should
support a variety of environments, such as kvm, but also something like
userspace apps. So I cannot make assumptions about things like "pci
interrupts", etc.
virtio doesn't make these assumptions either. The only difference I see
is that you separate notification from the ring structure.
By your own words, the exit to userspace is "prohibitively expensive",
so that is either true or its not. If its 2 microseconds, show me.
In user/test/x86/vmexit.c, change 'cpuid' to 'out %al, $0'; drop the
printf() in kvmctl.c's test_outb().
I get something closer to 4 microseconds, but that's on a two year old
machine; It will be around two on Nehalems.
My 'prohibitively expensive' is true only if you exit every packet.
--
error compiling committee.c: too many arguments to function
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