On Fri, Dec 07, 2012 at 11:32:08AM -0700, Alex Williamson wrote: > On Fri, 2012-12-07 at 13:17 -0500, Jason Baron wrote: > > On Thu, Dec 06, 2012 at 03:20:37PM -0700, Alex Williamson wrote: > > > The API documents that only flags and guest physical memory space can > > > be modified on an existing slot, but we don't enforce that the > > > userspace address cannot be modified. Instead we just ignore it. > > > This means that a user may think they've successfully moved both the > > > guest and user addresses, when in fact only the guest address changed. > > > Check and error instead. > > > > > > Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx> > > > --- > > > virt/kvm/kvm_main.c | 8 +++++++- > > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > > > index e426704..93213e1 100644 > > > --- a/virt/kvm/kvm_main.c > > > +++ b/virt/kvm/kvm_main.c > > > @@ -779,13 +779,19 @@ int __kvm_set_memory_region(struct kvm *kvm, > > > > > > r = -ENOMEM; > > > > > > - /* Allocate if a slot is being created */ > > > + /* > > > + * Allocate if a slot is being created. If modifying a slot, > > > + * the userspace_addr cannot change. > > > + */ > > > if (!old.npages) { > > > new.user_alloc = user_alloc; > > > new.userspace_addr = mem->userspace_addr; > > > > > > if (kvm_arch_create_memslot(&new, npages)) > > > goto out_free; > > > + } else if (mem->userspace_addr != old.userspace_addr) { > > > + r = -EINVAL; > > > + goto out_free; > > > } > > > > > > /* Allocate page dirty bitmap if needed */ > > > > > > > hmmm...does this mean that on a 'destroy', where npages is 0, the user > > has to set up userspace_addr correctly? If so, that would appear to be > > an unwanted change in semantics here. > > Good point, it does change that. We could make this be (npages && > mem->userspace_addr != old.userspace_addr) to avoid that case. Thanks, > > Alex > Yup, that works for me. Thanks, -Jason -- 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