kvm: Add an option to force context sync on kvm entry/exit

This changeset adds an option to force the kvm-based CPUs to always
synchronize the gem5 thread context representation on entry/exit into
the kernel. This is very useful for debugging. Unfortunately, it is
also the only way to get reliable register contents when using remote
gdb functionality. The long-term solution for the latter would be to
implement a kvm-specific thread context.

Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Reviewed-by: Alexandru Dutu <alexandru.dutu@amd.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/src/cpu/kvm/base.hh b/src/cpu/kvm/base.hh
index dd27328be..7ff0cab5c 100644
--- a/src/cpu/kvm/base.hh
+++ b/src/cpu/kvm/base.hh
@@ -575,6 +575,12 @@ class BaseKvmCPU : public BaseCPU
     KVMCpuPort instPort;
 
     /**
+     * Be conservative and always synchronize the thread context on
+     * KVM entry/exit.
+     */
+    const bool alwaysSyncTC;
+
+    /**
      * Is the gem5 context dirty? Set to true to force an update of
      * the KVM vCPU state upon the next call to kvmRun().
      */