On Sat, Aug 23, 2008 at 12:50:25PM +0300, Muli Ben-Yehuda wrote: > On Sat, Aug 23, 2008 at 12:33:46PM +0300, Avi Kivity wrote: > > > So long as there is no potential for performance or security impact, > > having pvdma turned on automatically is better. We could still have > > dma=noparavirt to disable it. > > pvdma has advantages and disadvantages. It has a significant > performance impact (compared to direct map) but it also let us avoid > pinning all of the guest's memory. I this this should be a guest > decision whether to use it or not, so 'dma=noparavirt' to disable it > seems reasonable.
Just to clarify---I am talking about pvdma WITH an iommu, where there are no protection implications to having pvdma. pvdma without an IOMMU is a whole different ballgame and means we trust the guest---that should definitely be a host option, not a default. Cheers, Muli -- Workshop on I/O Virtualization (WIOV '08) Co-located with OSDI '08, Dec 2008, San Diego, CA http://www.usenix.org/wiov08 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
