On Wed, Jun 17, 2015 at 02:23:39PM +0200, Igor Mammedov wrote: > On Wed, 17 Jun 2015 13:51:56 +0200 > "Michael S. Tsirkin" <mst@xxxxxxxxxx> wrote: > > > On Wed, Jun 17, 2015 at 01:48:03PM +0200, Igor Mammedov wrote: > > > > > So far it's kernel limitation and this patch fixes crashes > > > > > that users see now, with the rest of patches enabling performance > > > > > not to regress. > > > > > > > > When I say regression I refer to an option to limit the array > > > > size again after userspace started using the larger size. > > > Is there a need to do so? > > > > Considering userspace can be malicious, I guess yes. > I don't think it's a valid concern in this case, > setting limit back from 509 to 64 will not help here in any way, > userspace still can create as many vhost instances as it needs > to consume memory it desires. Not really since vhost char device isn't world-accessible. It's typically opened by a priveledged tool, the fd is then passed to an unpriveledged userspace, or permissions dropped. > > > > > Userspace that cares about memory footprint won't use many slots > > > keeping it low and user space that can't do without many slots > > > or doesn't care will have bigger memory footprint. > > > > We really can't trust userspace to do the right thing though. > > -- 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
