[PATCH v1 00/28] Introduce support for confidential guest reset

[Ani Sinha <anisinha@redhat.com>]

This change introduces support for confidential guests
(SEV-ES, SEV-SNP and TDX) to reset/reboot just like other non-confidential
guests. Currently, a reboot intiated from the confidential guest results
in termination of the QEMU hypervisor as the CPUs are not resettable. As the
initial state of the guest including private memory is locked and encrypted,
the contents of that memory will not be accessible post reset. Hence a new
KVM file descriptor must be opened to create a new confidential VM context
closing the old one. All KVM VM specific ioctls must be called again. New
VCPU file descriptors must be created against the new KVM fd and most VCPU
ioctls must be called again as well.

This change perfoms closing of the old KVM fd and creating a new one. After
the new KVM fd is opened, all generic and architecture specific ioctl calls
are issued again. Notifiers are added to notify subsystems that:
- The KVM file fd is about to be changed to state sync-ing from KVM to QEMU
  should be done if required.
- The KVM file fd has changed, so ioctl calls to the new KVM fd has to be
  performed again.
- That new VCPU fds are created so that VCPU ioctl calls must be called again
  where required.

Specific subsystems use these notifiers to re-issue ioctl calls where required.

Changes are made to SEV and TDX modules to reinitialize the confidential guest
state and seal it again. Along the way, some bug fixes are made so that some
initialization functions can be called again. Some refactoring of existing
code is done so that both init and reset paths can use them.

Tested on TDX and SEV-SNP.
CI pipeline passes: https://gitlab.com/anisinha/qemu/-/pipelines/2211550528
Rebased on top of version 10.2.0-rc3

CC: pbonzini@redhat.com
CC: kraxel@redhat.com
CC: vkuznets@redhat.com

Ani Sinha (28):
  i386/kvm: avoid installing duplicate msr entries in msr_handlers
  hw/accel: add a per-accelerator callback to change VM accelerator
    handle
  system/physmem: add helper to reattach existing memory after KVM VM fd
    change
  accel/kvm: add changes required to support KVM VM file descriptor
    change
  accel/kvm: mark guest state as unprotected after vm file descriptor
    change
  accel/kvm: add a notifier to indicate KVM VM file descriptor has
    changed
  kvm/i386: implement architecture support for kvm file descriptor
    change
  hw/i386: refactor x86_bios_rom_init for reuse in confidential guest
    reset
  kvm/i386: reload firmware for confidential guest reset
  accel/kvm: Add notifier to inform that the KVM VM file fd is about to
    be changed
  accel/kvm: rebind current VCPUs to the new KVM VM file descriptor upon
    reset
  i386/tdx: refactor TDX firmware memory initialization code into a new
    function
  i386/tdx: finalize TDX guest state upon reset
  i386/tdx: add a pre-vmfd change notifier to reset tdx state
  i386/sev: add migration blockers only once
  i386/sev: add notifiers only once
  i386/sev: free existing launch update data and kernel hashes data on
    init
  i386/sev: add support for confidential guest reset
  hw/vfio: generate new file fd for pseudo device and rebind existing
    descriptors
  kvm/i8254: add support for confidential guest reset
  hw/hyperv/vmbus: add support for confidential guest reset
  accel/kvm: add a per-confidential class callback to unlock guest state
  kvm/xen-emu: re-initialize capabilities during confidential guest
    reset
  kvm/xen_evtchn: add support for confidential guest reset
  ppc/openpic: create a new openpic device and reattach mem region on
    coco reset
  kvm/vcpu: add notifiers to inform vcpu file descriptor change
  kvm/i386/apic: set local apic after vcpu file descriptors changed
  kvm/clock: add support for confidential guest reset

 accel/kvm/kvm-all.c                         | 354 +++++++++++++++++---
 accel/stubs/kvm-stub.c                      |  26 ++
 hw/hyperv/vmbus.c                           |  30 ++
 hw/i386/kvm/apic.c                          |  13 +
 hw/i386/kvm/clock.c                         |  56 ++++
 hw/i386/kvm/i8254.c                         |  84 +++--
 hw/i386/kvm/xen_evtchn.c                    | 100 +++++-
 hw/i386/x86-common.c                        |  50 ++-
 hw/intc/openpic_kvm.c                       | 108 ++++--
 hw/vfio/helpers.c                           |  81 ++++-
 include/accel/accel-ops.h                   |   1 +
 include/hw/i386/apic_internal.h             |   1 +
 include/hw/i386/x86.h                       |   5 +-
 include/system/confidential-guest-support.h |  27 ++
 include/system/kvm.h                        |  54 +++
 include/system/physmem.h                    |   1 +
 system/physmem.c                            |  28 ++
 system/runstate.c                           |  31 +-
 target/arm/kvm.c                            |   5 +
 target/i386/kvm/kvm.c                       | 189 +++++++++--
 target/i386/kvm/tdx.c                       | 145 ++++++--
 target/i386/kvm/tdx.h                       |   1 +
 target/i386/kvm/xen-emu.c                   |  45 ++-
 target/i386/sev.c                           | 110 +++++-
 target/loongarch/kvm/kvm.c                  |   5 +
 target/mips/kvm.c                           |   5 +
 target/ppc/kvm.c                            |   5 +
 target/riscv/kvm/kvm-cpu.c                  |   5 +
 target/s390x/kvm/kvm.c                      |   5 +
 29 files changed, 1382 insertions(+), 188 deletions(-)

-- 
2.42.0