On 09/30/15 15:03, Michael S. Tsirkin wrote:

On Wed, Sep 30, 2015 at 02:53:19PM +0300, Vlad Zolotarov wrote:

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On 09/30/15 14:41, Michael S. Tsirkin wrote:

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On Wed, Sep 30, 2015 at 02:26:01PM +0300, Vlad Zolotarov wrote:

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The whole idea is to bypass kernel. Especially for networking...

... on dumb hardware that doesn't support doing that securely.

On a very capable HW that supports whatever security requirements needed
(e.g. 82599 Intel's SR-IOV VF devices).

Network card type is irrelevant as long as you do not have an IOMMU,
otherwise you would just use e.g. VFIO.

Sorry, but I don't follow your logic here - Amazon EC2 environment is a 
example where there *is* iommu but it's not virtualized and thus VFIO is 
useless and there is an option to use directly assigned SR-IOV 
networking device there where using the kernel drivers impose a 
performance impact compared to user space UIO-based user space kernel 
bypass mode of usage. How is it irrelevant? Could u, pls, clarify your 
point?

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Colour me unimpressed.