[PATCH 0/4] KVM: fix KVM_EXIT_SYSTEM_EVENT mess

[Paolo Bonzini <pbonzini@redhat.com>]

The KVM_SYSTEM_EVENT_NDATA_VALID mechanism that was introduced
contextually with KVM_SYSTEM_EVENT_SEV_TERM is not a good match
for ARM and RISC-V, which want to communicate information even
for existing KVM_SYSTEM_EVENT_* constants.  Userspace is not ready
to filter out bit 31 of type, and fails to process the
KVM_EXIT_SYSTEM_EVENT exit.

Therefore, tie the availability of ndata to a system capability;
if the capability is present, ndata is always valid, so patch 1
makes x86 always initialize it.  Then patches 2 and 3 fix
ARM and RISC-V compilation and patch 4 enables the capability.

Only compiled on x86, waiting for acks.

Paolo

Paolo Bonzini (4):
  KVM: x86: always initialize system_event.ndata
  KVM: ARM: replace system_event.flags with ndata and data[0]
  KVM: RISC-V: replace system_event.flags with ndata and data[0]
  KVM: tell userspace that system_event.ndata is valid

 Documentation/virt/kvm/api.rst        | 29 +++++++++++++++------------
 arch/arm64/kvm/psci.c                 |  3 ++-
 arch/riscv/include/asm/kvm_vcpu_sbi.h |  2 +-
 arch/riscv/kvm/vcpu_sbi.c             |  5 +++--
 arch/riscv/kvm/vcpu_sbi_replace.c     |  4 ++--
 arch/riscv/kvm/vcpu_sbi_v01.c         |  2 +-
 arch/x86/kvm/svm/sev.c                |  3 +--
 arch/x86/kvm/x86.c                    |  2 ++
 include/uapi/linux/kvm.h              |  2 +-
 virt/kvm/kvm_main.c                   |  1 +
 10 files changed, 30 insertions(+), 23 deletions(-)

-- 
2.31.1