Re: [PATCH v3 2/3] uio_pci_generic: add MSI/MSI-X support

[Michael S. Tsirkin]

On Thu, Oct 08, 2015 at 10:59:10AM +0300, Gleb Natapov wrote:
> I do not remember this been an issue when uio_generic was accepted
> into the kernel. The reason was because it meant to be accessible by root
> only.

No - because it does not need bus mastering. So it can be used safely
with some devices.

[mst@robin linux]$ git grep pci_set_master|wc -l 533
[mst@robin linux]$ git grep pci_enable|wc -l 1597

Looks like about 2/3 devices don't need to be bus masters.

It's up to admin not to bind it to devices, and that is unfortunate,
but manually binding an incorrect driver to a device is generally
a hard problem to solve.

> > There's also drivers/vfio/virqfd.c which deals
> > with sending interrupts over eventfds correctly.
> > 
> As opposite to this patch that deals with them incorrectly? In what way?

cleanup on fd close is not handled.

-- 
MST
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