KVM: nVMX: Rely on kvm_vcpu_unmap() to track validity of eVMCS mapping

KVM: nVMX: Rely on kvm_vcpu_unmap() to track validity of eVMCS mapping

Remove the explicit evmptr12 validity check when deciding whether or not
to unmap the eVMCS pointer, and instead rely on kvm_vcpu_unmap() to play
nice with a NULL map->hva, i.e. to do nothing if the map is invalid.

Note, vmx->nested.hv_evmcs_map is zero-allocated along with the rest of
vcpu_vmx, i.e. the map starts out invalid/NULL.

Tested-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Tested-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20241010182427.1434605-24-seanjc@google.com>