vmm: Enable gdbstub on AArch64

The `gva_translate` function is still missing, it will be added with a
separate commit.

Signed-off-by: Michael Zhao <michael.zhao@arm.com>

vmm/src/gdb.rs

@@ -24,6 +24,10 @@ use gdbstub::{
         Target, TargetError, TargetResult,
     },
 };
+#[cfg(target_arch = "aarch64")]
+use gdbstub_arch::aarch64::reg::AArch64CoreRegs as CoreRegs;
+#[cfg(target_arch = "aarch64")]
+use gdbstub_arch::aarch64::AArch64 as GdbArch;
 #[cfg(target_arch = "x86_64")]
 use gdbstub_arch::x86::reg::X86_64CoreRegs as CoreRegs;
 #[cfg(target_arch = "x86_64")]
@@ -31,7 +35,6 @@ use gdbstub_arch::x86::X86_64_SSE as GdbArch;
 use std::{os::unix::net::UnixListener, sync::mpsc};
 use vm_memory::{GuestAddress, GuestMemoryError};
 
-#[cfg(target_arch = "x86_64")]
 type ArchUsize = u64;
 
 #[derive(Debug)]
@@ -121,7 +124,6 @@ pub struct GdbStub {
     gdb_sender: mpsc::Sender<GdbRequest>,
     gdb_event: vmm_sys_util::eventfd::EventFd,
     vm_event: vmm_sys_util::eventfd::EventFd,
-
     hw_breakpoints: Vec<GuestAddress>,
     single_step: bool,
 }