target/i386: kvm: Block migration for vCPUs exposed with nested virtualization

target/i386: kvm: Block migration for vCPUs exposed with nested virtualization

Commit d98f26073beb ("target/i386: kvm: add VMX migration blocker")
added a migration blocker for vCPU exposed with Intel VMX.
However, migration should also be blocked for vCPU exposed with
AMD SVM.

Both cases should be blocked because QEMU should extract additional
vCPU state from KVM that should be migrated as part of vCPU VMState.
E.g. Whether vCPU is running in guest-mode or host-mode.

Fixes: d98f26073beb ("target/i386: kvm: add VMX migration blocker")
Reviewed-by: Maran Wilson <[email protected]>
Signed-off-by: Liran Alon <[email protected]>
Message-Id: <20190619162140[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>