On Mon, 24 Feb 2020 06:40:36 -0500 Christian Borntraeger <borntraeger@xxxxxxxxxx> wrote: > From: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> > > This provides the basic ultravisor calls and page table handling to cope > with secure guests: > - provide arch_make_page_accessible > - make pages accessible after unmapping of secure guests > - provide the ultravisor commands convert to/from secure > - provide the ultravisor commands pin/unpin shared > - provide callbacks to make pages secure (inacccessible) > - we check for the expected pin count to only make pages secure if the > host is not accessing them > - we fence hugetlbfs for secure pages > - add missing radix-tree include into gmap.h > > The basic idea is that a page can have 3 states: secure, normal or > shared. The hypervisor can call into a firmware function called > ultravisor that allows to change the state of a page: convert from/to > secure. The convert from secure will encrypt the page and make it > available to the host and host I/O. The convert to secure will remove > the host capability to access this page. > The design is that on convert to secure we will wait until writeback and > page refs are indicating no host usage. At the same time the convert > from secure (export to host) will be called in common code when the > refcount or the writeback bit is already set. This avoids races between > convert from and to secure. > > Then there is also the concept of shared pages. Those are kind of secure > where the host can still access those pages. We need to be notified when > the guest "unshares" such a page, basically doing a convert to secure by > then. There is a call "pin shared page" that we use instead of convert > from secure when possible. > > We do use PG_arch_1 as an optimization to minimize the convert from > secure/pin shared. > > Several comments have been added in the code to explain the logic in > the relevant places. > > Co-developed-by: Ulrich Weigand <Ulrich.Weigand@xxxxxxxxxx> > Signed-off-by: Ulrich Weigand <Ulrich.Weigand@xxxxxxxxxx> > Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx> > Acked-by: David Hildenbrand <david@xxxxxxxxxx> > Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > [borntraeger@xxxxxxxxxx: patch merging, splitting, fixing] > Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx> > --- > arch/s390/include/asm/gmap.h | 4 + > arch/s390/include/asm/mmu.h | 2 + > arch/s390/include/asm/mmu_context.h | 1 + > arch/s390/include/asm/page.h | 5 + > arch/s390/include/asm/pgtable.h | 35 ++++- > arch/s390/include/asm/uv.h | 31 ++++ > arch/s390/kernel/uv.c | 227 ++++++++++++++++++++++++++++ > 7 files changed, 300 insertions(+), 5 deletions(-) My mm-fu is not very strong; but this looks sane to me. Acked-by: Cornelia Huck <cohuck@xxxxxxxxxx>
