Address Jordan's feedback

sled-agent/src/config.rs

@@ -51,8 +51,8 @@ pub struct Config {
     pub sidecar_revision: SidecarRevision,
     /// Optional percentage of DRAM to reserve for guest memory
     pub vmm_reservoir_percentage: Option<u8>,
-    /// Optional DRAM to reserve for guest memory in MiB (cannot be used with
-    /// vmm_reservoir_percentage).
+    /// Optional DRAM to reserve for guest memory in MiB (mutually exclusive
+    /// option with vmm_reservoir_percentage).
     pub vmm_reservoir_size_mb: Option<u32>,
     /// Optional swap device size in GiB
     pub swap_device_size_gb: Option<u32>,

sled-agent/src/instance_manager.rs

@@ -141,7 +141,8 @@ impl InstanceManager {
             ReservoirMode::Percentage(percent) => {
                 if !matches!(percent, 1..=99) {
                     return Err(Error::ReservoirConfig(format!(
-                        "reservoir percentage of {} must be between 0 and 100",
+                        "VMM reservoir percentage of {} must be between 0 and \
+                        100",
                         percent
                     )));
                 };

sled-agent/src/sled_agent.rs

@@ -378,8 +378,8 @@ impl SledAgent {
             (Some(p), None) => ReservoirMode::Percentage(p),
             (None, Some(mb)) => ReservoirMode::Size(mb),
             (Some(_), Some(_)) => panic!(
-                "cannot specify vmm_reservoir_percentage and \
-                vmm_reservoir_size_mb at the same time"
+                "only one of vmm_reservoir_percentage and \
+                vmm_reservoir_size_mb is allowed"
             ),
         };