petri: lower severity of com3 emitted logs for all vmm_tests (#2003)

#1937 introduced new vmm_tests which seem to be flaky as they will
occasionally timeout. Upon further investigation, the following message
can be observed in the petri logs: `hv_vmbus: probe failed for device
766e96f8-2ceb-437e-afe3-a93169e48a7b`. It's likely that openhcl is busy
with other tasks (such as writing to com3) so it is unable to handle the
vmbus probe request from vtl0. This PR attempts to fix that by only
emitting high severity logs once kmsg is available.

---------

Co-authored-by: Daman Mulye <[email protected]>

Author: damanm24

petri/src/vm/mod.rs

@@ -228,7 +228,8 @@ impl<T: PetriVmmBackend> PetriVmBuilder<T> {
     /// event (if configured). Does not configure and start pipette. Should
     /// only be used for testing platforms that pipette does not support.
     pub async fn run_without_agent(self) -> anyhow::Result<PetriVm<T>> {
-        self.run_core().await
+        let (vm, _) = self.run_core(false).await?;
+        Ok(vm)
     }
 
     /// Build and run the VM, then wait for the VM to emit the expected boot
@@ -237,12 +238,14 @@ impl<T: PetriVmmBackend> PetriVmBuilder<T> {
         assert!(self.config.agent_image.is_some());
         assert!(self.config.agent_image.as_ref().unwrap().contains_pipette());
 
-        let mut vm = self.run_core().await?;
-        let client = vm.wait_for_agent().await?;
-        Ok((vm, client))
+        let (vm, agent) = self.run_core(true).await?;
+        Ok((vm, agent.unwrap()))
     }
 
-    async fn run_core(self) -> anyhow::Result<PetriVm<T>> {
+    async fn run_core(
+        self,
+        with_agent: bool,
+    ) -> anyhow::Result<(PetriVm<T>, Option<PipetteClient>)> {
         let arch = self.config.arch;
         let expect_reset = self.expect_reset();
 
@@ -268,9 +271,22 @@ impl<T: PetriVmmBackend> PetriVmBuilder<T> {
             vm.wait_for_reset_core().await?;
         }
 
+        let client = if with_agent {
+            Some(vm.wait_for_agent().await?)
+        } else {
+            None
+        };
+
+        if with_agent {
+            let result = vm.set_console_loglevel(3).await;
+            if result.is_err() {
+                tracing::warn!("failed to set console loglevel: {}", result.unwrap_err());
+            }
+        }
+
         vm.wait_for_expected_boot_event().await?;
 
-        Ok(vm)
+        Ok((vm, client))
     }
 
     fn expect_reset(&self) -> bool {
@@ -675,7 +691,12 @@ impl<T: PetriVmmBackend> PetriVm<T> {
     /// Wait for the VM to reset and pipette to connect.
     pub async fn wait_for_reset(&mut self) -> anyhow::Result<PipetteClient> {
         self.wait_for_reset_no_agent().await?;
-        self.wait_for_agent().await
+        let client = self.wait_for_agent().await?;
+        let result = self.set_console_loglevel(3).await;
+        if result.is_err() {
+            tracing::warn!("failed to set console loglevel: {}", result.unwrap_err());
+        }
+        Ok(client)
     }
 
     async fn wait_for_reset_core(&mut self) -> anyhow::Result<()> {
@@ -866,6 +887,26 @@ impl<T: PetriVmmBackend> PetriVm<T> {
             anyhow::bail!("VM is not configured with OpenHCL")
         }
     }
+
+    async fn set_console_loglevel(&self, level: u8) -> anyhow::Result<()> {
+        match self.openhcl_diag() {
+            Ok(diag) => {
+                diag.kmsg().await?;
+                let res = diag
+                    .run_vtl2_command("dmesg", &["-n", &level.to_string()])
+                    .await?;
+
+                if !res.exit_status.success() {
+                    anyhow::bail!("failed to set console loglevel: {:?}", res);
+                }
+            }
+            Err(e) => {
+                anyhow::bail!("failed to open VTl2 diagnostic channel: {}", e);
+            }
+        };
+
+        Ok(())
+    }
 }
 
 /// A running VM that tests can interact with.