On Fri, Dec 04, 2020 at 04:44:12PM +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 securable-guest-memory machine
> 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 securable-guest-memory=pef0
>
> Signed-off-by: David Gibson <david@xxxxxxxxxxxxxxxxxxxxx>
> Acked-by: Ram Pai <linuxram@xxxxxxxxxx>
> ---
> 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 ---
> 6 files changed, 152 insertions(+), 24 deletions(-)
> create mode 100644 hw/ppc/pef.c
> create mode 100644 include/hw/ppc/pef.h
>
> diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build
> index ffa2ec37fa..218631c883 100644
> --- a/hw/ppc/meson.build
> +++ b/hw/ppc/meson.build
> @@ -27,6 +27,7 @@ ppc_ss.add(when: 'CONFIG_PSERIES', if_true: files(
> 'spapr_nvdimm.c',
> 'spapr_rtas_ddw.c',
> 'spapr_numa.c',
> + 'pef.c',
> ))
> ppc_ss.add(when: 'CONFIG_SPAPR_RNG', if_true: files('spapr_rng.c'))
> ppc_ss.add(when: ['CONFIG_PSERIES', 'CONFIG_LINUX'], if_true: files(
> diff --git a/hw/ppc/pef.c b/hw/ppc/pef.c
> new file mode 100644
> index 0000000000..3ae3059cfe
> --- /dev/null
> +++ b/hw/ppc/pef.c
> @@ -0,0 +1,115 @@
> +/*
> + * PEF (Protected Execution Facility) for POWER support
> + *
> + * Copyright David Gibson, Redhat Inc. 2020
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + *
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "qapi/error.h"
> +#include "qom/object_interfaces.h"
> +#include "sysemu/kvm.h"
> +#include "migration/blocker.h"
> +#include "exec/securable-guest-memory.h"
> +#include "hw/ppc/pef.h"
> +
> +#define TYPE_PEF_GUEST "pef-guest"
> +#define PEF_GUEST(obj) \
> + OBJECT_CHECK(PefGuestState, (obj), TYPE_PEF_GUEST)
> +
> +typedef struct PefGuestState PefGuestState;
> +
> +/**
> + * PefGuestState:
> + *
> + * The PefGuestState object is used for creating and managing a PEF
> + * guest.
> + *
> + * # $QEMU \
> + * -object pef-guest,id=pef0 \
> + * -machine ...,securable-guest-memory=pef0
> + */
> +struct PefGuestState {
> + Object parent_obj;
> +};
> +
> +#ifdef CONFIG_KVM
> +static int kvmppc_svm_init(Error **errp)
> +{
> + if (!kvm_check_extension(kvm_state, KVM_CAP_PPC_SECURABLE_GUEST)) {
^^^^^^^^^^^^^^^^^^^^^^^^^^
KVM defines this macro as KVM_CAP_PPC_SECURE_GUEST. Unless we patch KVM,
we are stuck with KVM_CAP_PPC_SECURE_GUEST.
RP
