On 03/15/2012 06:46 AM, Avi Kivity wrote:
On 03/15/2012 01:25 PM, Jan Kiszka wrote:
There was such vm exit (KVM_EXIT_HYPERCALL), but it was deemed to be a
bad idea.
BTW, this would help a lot in emulating hypercalls of other hypervisors
(or of KVM's VAPIC in the absence of in-kernel irqchip - I had to jump
through hoops therefore) in user space. Not all those hypercall handlers
actually have to reside in the KVM module.
That is true. On the other hand the hypercall ABI might go to pieces if
there was no central implementation.
Just declare that outl 0x505 is a megaultracall and s/vmcall/outb/g and call it
a day.
The performance difference between vmcall and outl is so tiny compared to the
cost of dropping to userspace that it really doesn't matter which instruction is
used.
Regards,
Anthony Liguori
--
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
