Re: [RFC] virtio-blk PCI backend

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Anthony Liguori wrote:
> +    case VIRTIO_PCI_QUEUE_NOTIFY:
> +	if (val < VIRTIO_PCI_QUEUE_MAX)
> +	    virtio_ring_kick(vdev, &vdev->vq[val]);
> +	break;
>   

I see you're not using hypercalls for this, presumably for compatibility
with -no-kvm.  Well I think I have a solution: advertise vmcall,
vmmcall, pio to some port, and int $some_vector as hypercall feature
bits in cpuid (for kvm, kvm, qemu, and kvm-lite respectively).  Early
setup code could patch the instruction as appropriate (I hear code
patching is now taught in second grade).

(kvm could advertise all four, or maybe just the first two)

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.


-------------------------------------------------------------------------
This SF.net email is sponsored by: Splunk Inc.
Still grepping through log files to find problems?  Stop.
Now Search log events and configuration files using AJAX and a browser.
Download your FREE copy of Splunk now >> http://get.splunk.com/