[PATCH 0/4] Confidential Guest Support: Introduce kvm_init() and kvm_reset() virtual functions

[Xiaoyao Li <xiaoyao.li@intel.com>]

This series was inspired and suggested by Daniel:
https://lore.kernel.org/qemu-devel/ZbfoQsEuv6_zwl3b@redhat.com/

I remove the rfc tag in this version, to get more attention.

Currently, different confidential VMs in different architectures have
their own specific *_kvm_init() (and some have *_kvm_reset()) exposed
for KVM stuff when it's a confidential VM. e.g., sev_kmv_init() for x86
SEV, pef_kvm_init() and pef_kvm_reset() for PPC PEF, and s390_pv_init()
for s390 PV VMs.

Introduce a generic .kvm_init() and .kvm_reset() functions in
ConfidentialGuestSupportClass, so that different cgs technologies in
different architectures can implement their own, while common interface
of cgs can be used.

This series implements two helper functions confidential_guest_kvm_init()
and confidential_guest_kvm_reset() in Patch 1. In the following patches,
they are used in each arch to replace specific exposed functions.
X86 will benefit more from the new generic interface  when TDX support is
added later.

There is one step forward possible, that calling
confidential_guest_kvm_init() before kvm_arch_init() in kvm_int() in
accel/kvm/kvm-all.c. This way, each arch doesn't need to call their
specific code in arch-specific code.
	
X86 fits it, however I'm not sure if ppc and s390 fit it as well.
Because currently, both ppc and s390 calls it in MachineClass->init().
I'm not sure if there is any order dependency and need input from
corresponding arch folks.


===
changes from RFC v1:
- remove RFC tag;
- move the !NULL check of ms->cgs into callers;
- delete whole sev-stub.c;

RFC v1:
https://lore.kernel.org/qemu-devel/20240206082852.3333299-1-xiaoyao.li@intel.com/

Xiaoyao Li (4):
  confidential guest support: Add kvm_init() and kvm_reset() in class
  i386/sev: Switch to use confidential_guest_kvm_init()
  ppc/pef: switch to use confidential_guest_kvm_init/reset()
  s390: Switch to use confidential_guest_kvm_init()

 hw/ppc/pef.c                              |   9 +-
 hw/ppc/spapr.c                            |  10 +-
 hw/s390x/s390-virtio-ccw.c                |   5 +-
 include/exec/confidential-guest-support.h |  34 +++++-
 include/hw/ppc/pef.h                      |  17 ---
 target/i386/kvm/kvm.c                     |  10 +-
 target/i386/kvm/meson.build               |   2 -
 target/i386/kvm/sev-stub.c                |  21 ----
 target/i386/sev.c                         | 120 +++++++++++-----------
 target/i386/sev.h                         |   2 -
 target/s390x/kvm/pv.c                     |   8 ++
 target/s390x/kvm/pv.h                     |  14 ---
 12 files changed, 126 insertions(+), 126 deletions(-)
 delete mode 100644 include/hw/ppc/pef.h
 delete mode 100644 target/i386/kvm/sev-stub.c

-- 
2.34.1