On Wed, Sep 12, 2012 at 06:34:33PM +0300, Avi Kivity wrote: > On 09/11/2012 05:39 PM, Marcelo Tosatti wrote: > > On Tue, Sep 11, 2012 at 12:18:22PM +0300, Avi Kivity wrote: > >> > The same can happen with slot deletion, for example. > >> > > >> > Userspace (which performed the modification which can result in faults > >> > to non-existant/read-only/.../new-tag memslot), must handle the faults > >> > properly or avoid the possibility for reference to memslot information > >> > from the past. > >> > > >> > I think its worthwhile to add a note about this in the API > >> > documentation: "The user of this interface is responsible for handling > >> > references to stale memslot information, either by handling > >> > exit notifications which reference stale memslot information or not > >> > allowing these notifications to exist by stopping all vcpus in userspace > >> > before performing modifications to the memslots map". > >> > >> Or we can drop the new interface and rely on userspace to perform the > >> lookup under its own locking rules. > >> > >> It's slow, but writes to ROM or ROM/device are rare anyway. > > > > Lookup what information? > > Where to dispatch the write. > > In fact userspace has to do that anyway if it's a ROM/device. There's > no way userspace can guess that unless we pass in the slot number (which > isn't synchronized with anything). Alright, do you prefer the details of this exit to be worked out later, when necessary, then? That is, not merge this particular patch of the series? -- 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
