On Tue, Jan 12, 2021 at 09:56:12AM +0000, Daniel P. Berrangé wrote:
> On Tue, Jan 12, 2021 at 03:45:05PM +1100, David Gibson wrote:
> > Some upcoming POWER machines have a system called PEF (Protected
> > Execution Facility) which uses a small ultravisor to allow guests to
> > run in a way that they can't be eavesdropped by the hypervisor. The
> > effect is roughly similar to AMD SEV, although the mechanisms are
> > quite different.
> >
> > Most of the work of this is done between the guest, KVM and the
> > ultravisor, with little need for involvement by qemu. However qemu
> > does need to tell KVM to allow secure VMs.
> >
> > Because the availability of secure mode is a guest visible difference
> > which depends on having the right hardware and firmware, we don't
> > enable this by default. In order to run a secure guest you need to
> > create a "pef-guest" object and set the confidential-guest-support
> > property to point to it.
> >
> > Note that this just *allows* secure guests, the architecture of PEF is
> > such that the guest still needs to talk to the ultravisor to enter
> > secure mode. Qemu has no directl way of knowing if the guest is in
> > secure mode, and certainly can't know until well after machine
> > creation time.
> >
> > To start a PEF-capable guest, use the command line options:
> > -object pef-guest,id=pef0 -machine confidential-guest-support=pef0
> >
> > Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> > ---
> > docs/confidential-guest-support.txt | 2 +
> > docs/papr-pef.txt | 30 ++++++++
> > hw/ppc/meson.build | 1 +
> > hw/ppc/pef.c | 115 ++++++++++++++++++++++++++++
> > hw/ppc/spapr.c | 10 +++
> > include/hw/ppc/pef.h | 26 +++++++
> > target/ppc/kvm.c | 18 -----
> > target/ppc/kvm_ppc.h | 6 --
> > 8 files changed, 184 insertions(+), 24 deletions(-)
> > create mode 100644 docs/papr-pef.txt
> > create mode 100644 hw/ppc/pef.c
> > create mode 100644 include/hw/ppc/pef.h
> >
>
> > +static const TypeInfo pef_guest_info = {
> > + .parent = TYPE_OBJECT,
> > + .name = TYPE_PEF_GUEST,
> > + .instance_size = sizeof(PefGuestState),
> > + .interfaces = (InterfaceInfo[]) {
> > + { TYPE_CONFIDENTIAL_GUEST_SUPPORT },
> > + { TYPE_USER_CREATABLE },
> > + { }
> > + }
> > +};
>
> IIUC, the earlier patch defines TYPE_CONFIDENTIAL_GUEST_SUPPORT
> as a object, but you're using it as an interface here. The later
> s390 patch uses it as a parent, which makes more sense given it
> is a declared as an object.
Oops, that's a holdover from an earlier version that used an
interface. Fixed.
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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