On Mon, Jan 9, 2023 at 10:21 AM Sean Christopherson seanjc@google.com wrote:
KVM: selftests: Use host's native hypercall instruction in kvm_hypercall()
On Wed, Dec 28, 2022, Vishal Annapurve wrote:
Invoke vmcall/vmmcall instructions from kvm_hypercall as per host CPU
() for functions, i.e. kvm_hypercall().
type.
s/type/vendor, "type" is too generic.
CVMs and current kvm_hyerpcall callers need to execute hypercall
CVM isn't a not ubiquitous acronym. I would avoid it entirely because "CVM" doesn't strictly imply memory encryption, e.g. KVM could still patch the guest in a pKVM-like implementation.
Use the host CPU's native hypercall instruction, i.e. VMCALL vs. VMMCALL, in kvm_hypercall(), as relying on KVM to patch in the native hypercall on a #UD for the "wrong" hypercall requires KVM_X86_QUIRK_FIX_HYPERCALL_INSN to be enabled and flat out doesn't work if guest memory is encrypted with a private key, e.g. for SEV VMs.
Ack, this makes sense.