Messages in this thread | | | Date | Wed, 2 Jun 2010 15:02:38 +0200 | From | Joerg Roedel <> | Subject | Re: [PATCH] VFIO driver: Non-privileged user level PCI drivers |
| |
On Wed, Jun 02, 2010 at 03:34:17PM +0300, Michael S. Tsirkin wrote: > On Wed, Jun 02, 2010 at 02:19:28PM +0200, Joerg Roedel wrote:
> you normally need device mapped to start DMA. > SHARE makes this bug more likely as you allow > switching domains: mmap could be done before switching.
We need to support domain switching anyway for iommu emulation in a guest. So if you consider this to be a problem (I don't) it will not go away with your proposal.
> > dev1 = open(); > > ioctl(dev2, SHARE, dev1); > > ioctl(dev3, SHARE, dev1); > > ioctl(dev4, SHARE, dev1); > > > > So we actually save an ioctl. > > I thought we had a BIND ioctl?
I can't remember a BIND ioctl in my proposal. I remember an UNBIND, but thats bad naming as you pointed out below. See my statement on this below too.
> You undo SHARE with UNBIND?
Thats bad naming, agreed. Lets keep UNSHARE. Point is, we only need one parameter to do this which removes any ambiguity:
ioctl(dev1, UNSHARE);
Joerg
| |