vmm: Automatically pause VM for coredump

If the VMM is not already paused then pause the VM prior to executing
the coredump and then resume it after. If the VM is already paused then
the original state is maintained.

Signed-off-by: Yi Wang <foxywang@tencent.com>

vmm/src/coredump.rs

@@ -36,6 +36,8 @@ pub struct DumpState {
 pub enum GuestDebuggableError {
     Coredump(anyhow::Error),
     CoredumpFile(std::io::Error),
+    Pause(vm_migration::MigratableError),
+    Resume(vm_migration::MigratableError),
 }
 
 pub trait GuestDebuggable: vm_migration::Pausable {