crosvm: defer IPC on set calls

If a plugin makes a set call on vcpu registers then we
can improve performance by deferring the IPC and instead
conbining the request with the next resume call.

BUG=None
TEST=build and run.

Change-Id: I4eb54a3f6eb30c98971aa2f099e3ea5899767eed
Signed-off-by: Matt Delco <delco@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1825262
Reviewed-by: Zach Reizner <zachr@chromium.org>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/plugin/vcpu.rs b/src/plugin/vcpu.rs
index 5ca27da..05970f7 100644
--- a/src/plugin/vcpu.rs
+++ b/src/plugin/vcpu.rs
@@ -444,6 +444,20 @@ impl PluginVcpu {
                 Err(SysError::new(EPROTO))
             } else if request.has_resume() {
                 send_response = false;
+                let resume = request.get_resume();
+                if !resume.get_regs().is_empty() {
+                    set_vcpu_state(vcpu, VcpuRequest_StateSet::REGS, resume.get_regs())?;
+                }
+                if !resume.get_sregs().is_empty() {
+                    set_vcpu_state(vcpu, VcpuRequest_StateSet::SREGS, resume.get_sregs())?;
+                }
+                if !resume.get_debugregs().is_empty() {
+                    set_vcpu_state(
+                        vcpu,
+                        VcpuRequest_StateSet::DEBUGREGS,
+                        resume.get_debugregs(),
+                    )?;
+                }
                 resume_data = Some(request.take_resume().take_data());
                 Ok(())
             } else if request.has_get_state() {