[v3,0/2] KVM: x86: guest interface for SEV live migration

Message

Paolo Bonzini April 29, 2021, 10:47 a.m. UTC

This is a reviewed version of the guest interface (hypercall+MSR)
for SEV live migration.  The differences lie mostly in the API
for userspace.  In particular:

- the CPUID feature is not exposed in KVM_GET_SUPPORTED_CPUID

- the hypercall must be enabled manually with KVM_ENABLE_CAP

- the MSR has sensible behavior if not filtered

Compared to v2, the KVM-provided behavior of the MSR is different:
it is set to 0 if the guest memory is encrypted, and 1 if it is not.
The idea is that the MSR is read-only if KVM_FEATURE_HC_PAGE_ENC_STATUS
is not exposed to the guest (it should only be exposed if the guest has
encrypted memory), but it also has a sensible value for non-encrypted
guests.  QEMU could however expose a "0" value for the special "-cpu
host,migratable=no" mode if it wanted.

Because of this new behavior, the CPUID bit are split.

Paolo

Ashish Kalra (1):
  KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall

Paolo Bonzini (1):
  KVM: x86: add MSR_KVM_MIGRATION_CONTROL

 Documentation/virt/kvm/api.rst        | 14 +++++++
 Documentation/virt/kvm/cpuid.rst      |  9 +++++
 Documentation/virt/kvm/hypercalls.rst | 21 ++++++++++
 Documentation/virt/kvm/msr.rst        | 14 +++++++
 arch/x86/include/asm/kvm-x86-ops.h    |  1 +
 arch/x86/include/asm/kvm_host.h       |  3 ++
 arch/x86/include/uapi/asm/kvm_para.h  |  5 +++
 arch/x86/kvm/cpuid.c                  |  3 +-
 arch/x86/kvm/svm/svm.c                |  1 +
 arch/x86/kvm/vmx/vmx.c                |  7 ++++
 arch/x86/kvm/x86.c                    | 56 +++++++++++++++++++++++++++
 include/uapi/linux/kvm.h              |  1 +
 include/uapi/linux/kvm_para.h         |  1 +
 13 files changed, 135 insertions(+), 1 deletion(-)