Re: [PATCH v4 08/14] virtio: pci: extend virtio pci rw api for vfio interface

On Mon, Jan 18, 2016 at 12:47 PM, Yuanhan Liu
[off-list ref] wrote:

On Mon, Jan 18, 2016 at 12:15:40PM +0530, Santosh Shukla wrote:

quoted

I am testing for virtio 1.0 and 0.95 for arm including your patch,
soon we;ll post the patch series that is rebased on / dependent on
below patchset:
- virtio 1.0
- vfio-noiommu
- KDRV check by huawei

IMO, we should start merging the dependent patches as because I'll

Yep, agreed. That's why I was keep pushing Huawei for ACK and
validation team for testing, although I have tested that. :)

quoted

have to rebase, then do regression across the platform at least for
x86/arm64 and it's quite a work now.

Beside that I have few question specific to vfio in virtio pmd driver;
- vfio don't need resource_init functionality as it uses struct
rte_pci_dev but it need parsing so to make sure
    1. user has setted no_iommu mode
    2. virtio pci device attached to vfio-no-iommu driver or not.

So for 1) I am thinking to add RTE_KDRV_VFIO_NOIOMMU mode and a helper
function like pci_vfio_is_iommu(), such that  pc_xxx_scan() function
updates dev->kdrv with RTE_KDRV_VFIO_NOIOMMU at driver probe time.

That sounds better to me. And that's also what I want to comment on
your another patch [09/14], that we should try to avoid getting UIO/VFIO
stuff inside virtio pmd driver, unless it's a must. (yes, I know
UIO is already an example here, but I don't like it, and badly, I don't
have the time to check if I can remove it.)

Understood, So I'm moving possible required driver/parsing check in
eal_pci.c rather keeping it in virtio, as those parsing/driver
dependency checks are generic, has nothing to do with virtio.

quoted

case 2) would check for _noiommu mode and then would verify that
driver is attached or not?

Sorry, very limited VFIO and noiommu knowledge, and I can't answer, so
far.

        --yliu

quoted

above two case applicable to both virtio spec 1.0 and 0.95. I have
done changes for those two case for v5 patch series,l any comment
welcome before I push patch for review.

Thanks.