Re: [PATCH v3 0/3] uio: add MSI/MSI-X support to uio_pci_generic driver

[Michael S. Tsirkin]

On Tue, Oct 06, 2015 at 07:09:11PM +0300, Avi Kivity wrote:
> 
> 
> On 10/06/2015 06:15 PM, Michael S. Tsirkin wrote:
> >>While it is possible that userspace malfunctions and accidentally programs
> >>MSI incorrectly, the risk is dwarfed by the ability of userspace to program
> >>DMA incorrectly.
> >That seems to imply that for the upstream kernel this is not a valid usecase at all.
> >
> 
> That is trivially incorrect, upstream pci_uio_generic is used with dpdk for
> years.

dpdk used to do polling for years. patch to use interrupts was posted in
june 2015.

>  Are dpdk applications an invalid use case?

The way dpdk is using UIO/sysfs is borderline at best, and can't be used
to justify new interfaces.  They have a more secure mode using VFIO.
That one's more reasonable.

-- 
MST
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