On Wed, 18 Mar 2020 10:30:36 -0400 Janosch Frank <fran...@linux.ibm.com> wrote:
> Ballooning in protected VMs can only be done when the guest shares the > pages it gives to the host. If pages are not shared, the integrity > checks will fail once those pages have been altered and are given back > to the guest. > > As we currently do not yet have a solution for this we will continue > like this: > > 1. We block ballooning now in QEMU (with this patch). > > 2. Later we will provide a change to virtio that removes the blocker > and adds VIRTIO_F_IOMMU_PLATFORM automatically by QEMU when doing the > protvirt switch. This is OK, as the balloon driver in Linux (the only > supported guest) will refuse to work with the IOMMU_PLATFORM feature > bit set. > > 3. Later, we can fix the guest balloon driver to accept the IOMMU > feature bit and correctly exercise sharing and unsharing of balloon > pages. > > Signed-off-by: Janosch Frank <fran...@linux.ibm.com> > Reviewed-by: David Hildenbrand <da...@redhat.com> > Reviewed-by: Christian Borntraeger <borntrae...@de.ibm.com> > Reviewed-by: Claudio Imbrenda <imbre...@linux.ibm.com> > --- > hw/s390x/s390-virtio-ccw.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) Reviewed-by: Cornelia Huck <coh...@redhat.com>
