[for-5.2,v4,00/10] Generalize memory encryption models

Message

David Gibson July 24, 2020, 2:57 a.m. UTC

A number of hardware platforms are implementing mechanisms whereby the
hypervisor does not have unfettered access to guest memory, in order
to mitigate the security impact of a compromised hypervisor.

AMD's SEV implements this with in-cpu memory encryption, and Intel has
its own memory encryption mechanism.  POWER has an upcoming mechanism
to accomplish this in a different way, using a new memory protection
level plus a small trusted ultravisor.  s390 also has a protected
execution environment.

The current code (committed or draft) for these features has each
platform's version configured entirely differently.  That doesn't seem
ideal for users, or particularly for management layers.

AMD SEV introduces a notionally generic machine option
"machine-encryption", but it doesn't actually cover any cases other
than SEV.

This series is a proposal to at least partially unify configuration
for these mechanisms, by renaming and generalizing AMD's
"memory-encryption" property.  It is replaced by a
"host-trust-limitation" property pointing to a platform specific
object which configures and manages the specific details.

Please apply.

Changes since v3:
 * Rebased
 * Added first cut at handling of s390 protected virtualization
Changes since RFCv2:
 * Rebased
 * Removed preliminary SEV cleanups (they've been merged)
 * Changed name to "host trust limitation"
 * Added migration blocker to the PEF code (based on SEV's version)
Changes since RFCv1:
 * Rebased
 * Fixed some errors pointed out by Dave Gilbert

David Gibson (10):
  host trust limitation: Introduce new host trust limitation interface
  host trust limitation: Handle memory encryption via interface
  host trust limitation: Move side effect out of
    machine_set_memory_encryption()
  host trust limitation: Rework the "memory-encryption" property
  host trust limitation: Decouple kvm_memcrypt_*() helpers from KVM
  host trust limitation: Add Error ** to HostTrustLimitation::kvm_init
  spapr: Add PEF based host trust limitation
  spapr: PEF: block migration
  host trust limitation: Alter virtio default properties for protected
    guests
  s390: Recognize host-trust-limitation option

 accel/kvm/kvm-all.c                  |  40 ++------
 accel/kvm/sev-stub.c                 |   7 +-
 accel/stubs/kvm-stub.c               |  10 --
 backends/Makefile.objs               |   2 +
 backends/host-trust-limitation.c     |  29 ++++++
 hw/core/machine.c                    |  61 +++++++++--
 hw/i386/pc_sysfw.c                   |   6 +-
 hw/s390x/pv.c                        |  61 +++++++++++
 include/exec/host-trust-limitation.h |  72 +++++++++++++
 include/hw/boards.h                  |   2 +-
 include/qemu/typedefs.h              |   1 +
 include/sysemu/kvm.h                 |  17 ---
 include/sysemu/sev.h                 |   4 +-
 target/i386/sev.c                    | 148 ++++++++++++---------------
 target/ppc/Makefile.objs             |   2 +-
 target/ppc/pef.c                     |  89 ++++++++++++++++
 16 files changed, 387 insertions(+), 164 deletions(-)
 create mode 100644 backends/host-trust-limitation.c
 create mode 100644 include/exec/host-trust-limitation.h
 create mode 100644 target/ppc/pef.c