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    SubjectRe: [PATCH 0/7] AlacrityVM guest drivers Reply-To:
    Hi Michael,

    >>> On 8/6/2009 at 4:19 AM, in message <>,
    "Michael S. Tsirkin" <> wrote:
    > On Mon, Aug 03, 2009 at 01:17:30PM -0400, Gregory Haskins wrote:
    >> (Applies to v2.6.31-rc5, proposed for linux-next after review is complete)
    > These are guest drivers, right?


    > Merging the guest first means relying on
    > kernel interface from an out of tree driver, which well might change
    > before it goes in.

    ABI compatibility is already addressed/handled, so even if that is true its not a problem.

    > Would it make more sense to start merging with the host side of the project?

    Not necessarily, no. These are drivers for a "device", so its no different than merging any other driver really. This is especially true since the hypervisor is also already published and freely available today, so anyone can start using it.

    >> This series implements the guest-side drivers for accelerated IO
    >> when running on top of the AlacrityVM hypervisor, the details of
    >> which you can find here:
    > Since AlacrityVM is kvm based, Cc

    I *can* do that, but there is nothing in these drivers that is KVM specific (its all pure PCI and VBUS). I've already made the general announcement about the project/ml cross posted to KVM for anyone that might be interested, but I figure I will spare the general KVM list the details unless something specifically pertains to, or affects, KVM. For instance, when I get to pushing the hypervisor side, I still need to work on getting that 'xinterface' patch to you guys. I would certainly be CC'ing kvm@vger when that happens since it modifies the KVM code.

    So instead, I would just encourage anyone interested (such as yourself) to join the alacrity list so I don't bother the KVM community unless absolutely necessary.

    >> This series includes the basic plumbing, as well as the driver for
    >> accelerated 802.x (ethernet) networking.
    > The graphs comparing virtio with vbus look interesting.
    > However, they do not compare apples to apples, do they?

    Yes, I believe they do. They represent the best that KVM has to offer (to my knowledge) vs the best that alacrityvm has to offer.

    > These compare userspace virtio with kernel vbus,

    vbus is a device model (akin to QEMU's device model). Technically, it was a comparison of userspace virtio-net (via QEMU), to kernel venet (via vbus),
    which I again stress is the state of the art for both to my knowledge.

    As I have explained before in earlier threads on kvm@vger, virtio is not mutually exclusive here. You can run the virtio protocol over the vbus model if someone were so inclined. In fact, I proposed this very idea to you a month or two ago but I believe you decided to go your own way and reinvent some other in-kernel model instead for your own reasons.

    >where for apples to apples comparison one would need to compare
    > kernel virtio with kernel vbus. Right?

    Again, it already *is* apples to apples as far as I am concerned.

    At the time I ran those numbers, there was certainly no in-kernel virtio model to play with. And to my knowledge, there isn't one now (I was never CC'd on the patches, and a cursory search of the KVM list isn't revealing one that was posted recently).

    To reiterate: kernel virtio-net (using ??) to kernel venet (vbus based) to kernel virtio-net (vbus, but doesnt exist yet) would be a fun bakeoff. If you have something for the kernel virtio-net, point me at it and I will try to include it in the comparison next time.

    Kind Regards,

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