From 23bb6292413fd4e60b293ec39043fd2ac29db663 Mon Sep 17 00:00:00 2001
From: Akira Moroo <retrage01@gmail.com>
Date: Fri, 4 Feb 2022 18:51:31 +0900
Subject: [PATCH] vmm: Add `stop_on_boot` to `Vm` to stop VM on boot

This commit adds `stop_on_boot` to `Vm` so that the VM stops before
starting on boot requested. This change is required to keep the target
VM stopped before a debugger attached as the user expected.

Signed-off-by: Akira Moroo <retrage01@gmail.com>
---
 vmm/src/vm.rs | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/vmm/src/vm.rs b/vmm/src/vm.rs
index 5ddb772f4..6d72b55c4 100644
--- a/vmm/src/vm.rs
+++ b/vmm/src/vm.rs
@@ -541,6 +541,7 @@ pub struct Vm {
     exit_evt: EventFd,
     #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
     hypervisor: Arc<dyn hypervisor::Hypervisor>,
+    stop_on_boot: bool,
 }
 
 impl Vm {
@@ -574,6 +575,8 @@ impl Vm {
         #[cfg(not(feature = "tdx"))]
         let force_iommu = false;
 
+        let stop_on_boot = false;
+
         let device_manager = DeviceManager::new(
             vm.clone(),
             config.clone(),
@@ -670,6 +673,7 @@ impl Vm {
             exit_evt,
             #[cfg(all(feature = "kvm", target_arch = "x86_64"))]
             hypervisor,
+            stop_on_boot,
         })
     }
 
@@ -2009,7 +2013,11 @@ impl Vm {
             return self.resume().map_err(Error::Resume);
         }
 
-        let new_state = VmState::Running;
+        let new_state = if self.stop_on_boot {
+            VmState::BreakPoint
+        } else {
+            VmState::Running
+        };
         current_state.valid_transition(new_state)?;
 
         // Load kernel if configured
@@ -2077,11 +2085,13 @@ impl Vm {
             self.vm.tdx_finalize().map_err(Error::FinalizeTdx)?;
         }
 
-        self.cpu_manager
-            .lock()
-            .unwrap()
-            .start_boot_vcpus()
-            .map_err(Error::CpuManager)?;
+        if new_state == VmState::Running {
+            self.cpu_manager
+                .lock()
+                .unwrap()
+                .start_boot_vcpus()
+                .map_err(Error::CpuManager)?;
+        }
 
         self.setup_signal_handler()?;
         self.setup_tty()?;