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 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
