On Wed, Feb 03, 2016 at 03:22:59PM +0000, Stefano Stabellini wrote: > On Wed, 3 Feb 2016, George Dunlap wrote: > > On 03/02/16 12:02, Stefano Stabellini wrote: > > > On Wed, 3 Feb 2016, Haozhong Zhang wrote: > > >> Or, we can make a file system on /dev/pmem0, create files on it, set > > >> the owner of those files to xen-qemuuser-domid$domid, and then pass > > >> those files to QEMU. In this way, non-root QEMU should be able to > > >> mmap those files. > > > > > > Maybe that would work. Worth adding it to the design, I would like to > > > read more details on it. > > > > > > Also note that QEMU initially runs as root but drops privileges to > > > xen-qemuuser-domid$domid before the guest is started. Initially QEMU > > > *could* mmap /dev/pmem0 while is still running as root, but then it > > > wouldn't work for any devices that need to be mmap'ed at run time > > > (hotplug scenario). > > > > This is basically the same problem we have for a bunch of other things, > > right? Having xl open a file and then pass it via qmp to qemu should > > work in theory, right? > > Is there one /dev/pmem? per assignable region? Otherwise it wouldn't be > safe.
Can be - which may be interleaved on multiple NVDIMMs. But we would operate on files (on the /dev/pmem which has an DAX enabled filesystem). _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
