On Thu, Jul 01, 2010 at 09:29:04AM -0600, Alex Williamson wrote: > On Tue, 2010-06-08 at 14:21 -0700, Tom Lyon wrote: > > +The VFIO_DMA_MASK ioctl is used to set the maximum permissible DMA address > > +(device dependent). It takes a single unsigned 64 bit integer as an argument. > > +This call also has the side effect of enabling PCI bus mastership. > > Hi Tom, > > This interface doesn't make sense for the MAP_IOVA user. Especially in > qemu, we have no idea what the DMA mask is for the device we're > assigning. It doesn't really matter though because the guest will use > bounce buffers internally once it loads the device specific drivers and > discovers the DMA mask. This only seems relevant if we're using a > DMA_MAP call that gets to pick the dmaaddr, so I'd propose we only make > this a required call for that interface, and create a separate ioctl for > actually enabling bus master. Thanks, > > Alex I expect there's no need for a separate ioctl to do this: you can do this by write to the control register. -- MST -- 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
