chore: revisit TODOs

Most TODOs are not actionable and are deleted.
Remaining are left as is or updated.

Signed-off-by: Egor Lazarchuk <yegorlz@amazon.co.uk>

Author: ShadowCurse

src/acpi-tables/src/aml.rs

@@ -160,8 +160,6 @@ pub struct Name {
 
 impl Aml for Name {
     fn append_aml_bytes(&self, bytes: &mut Vec<u8>) -> Result<(), AmlError> {
-        // TODO: Refactor this to make more efficient but there are
-        // lifetime/ownership challenges.
         bytes.extend_from_slice(&self.bytes);
         Ok(())
     }

src/firecracker/src/metrics.rs

@@ -60,22 +60,19 @@ impl MutEventSubscriber for PeriodicMetrics {
         let source = event.fd();
         let event_set = event.event_set();
 
-        // TODO: also check for errors. Pending high level discussions on how we want
-        // to handle errors in devices.
         let supported_events = EventSet::IN;
-        if !supported_events.contains(event_set) {
+        if supported_events.contains(event_set) {
+            if source == self.write_metrics_event_fd.as_raw_fd() {
+                self.write_metrics_event_fd.read();
+                self.write_metrics();
+            } else {
+                error!("Spurious METRICS event!");
+            }
+        } else {
             warn!(
                 "Received unknown event: {:?} from source: {:?}",
                 event_set, source
             );
-            return;
-        }
-
-        if source == self.write_metrics_event_fd.as_raw_fd() {
-            self.write_metrics_event_fd.read();
-            self.write_metrics();
-        } else {
-            error!("Spurious METRICS event!");
         }
     }
 

src/vmm/src/arch/aarch64/vcpu.rs

@@ -489,8 +489,6 @@ impl Peripherals {
     /// Returns error or enum specifying whether emulation was handled or interrupted.
     pub fn run_arch_emulation(&self, exit: VcpuExit) -> Result<VcpuEmulation, VcpuError> {
         METRICS.vcpu.failures.inc();
-        // TODO: Are we sure we want to finish running a vcpu upon
-        // receiving a vm exit that is not necessarily an error?
         error!("Unexpected exit reason on vcpu run: {:?}", exit);
         Err(VcpuError::UnhandledKvmExit(format!("{:?}", exit)))
     }

src/vmm/src/arch/x86_64/regs.rs

@@ -361,9 +361,8 @@ mod tests {
             ..Default::default()
         };
         let actual_fpu: kvm_fpu = vcpu.get_fpu().unwrap();
-        // TODO: auto-generate kvm related structures with PartialEq on.
         assert_eq!(expected_fpu.fcw, actual_fpu.fcw);
-        // Setting the mxcsr register from kvm_fpu inside setup_fpu does not influence anything.
+        // TODO: Setting the mxcsr register from kvm_fpu inside setup_fpu does not influence anything.
         // See 'kvm_arch_vcpu_ioctl_set_fpu' from arch/x86/kvm/x86.c.
         // The mxcsr will stay 0 and the assert below fails. Decide whether or not we should
         // remove it at all.

src/vmm/src/arch/x86_64/vcpu.rs

@@ -243,7 +243,7 @@ impl KvmVcpu {
         let extra_msrs = cpuid::common::msrs_to_save_by_cpuid(&kvm_cpuid);
         self.msrs_to_save.extend(extra_msrs);
 
-        // TODO: Some MSRs depend on values of other MSRs. This dependency will need to
+        // NOTE: Some MSRs depend on values of other MSRs. This dependency will need to
         // be implemented.
 
         // By this point we know that at snapshot, the list of MSRs we need to
@@ -586,9 +586,6 @@ impl KvmVcpu {
             .map_err(KvmVcpuError::VcpuGetDebugRegs)?;
         let lapic = self.fd.get_lapic().map_err(KvmVcpuError::VcpuGetLapic)?;
         let tsc_khz = self.get_tsc_khz().ok().or_else(|| {
-            // v0.25 and newer snapshots without TSC will only work on
-            // the same CPU model as the host on which they were taken.
-            // TODO: Add negative test for this warning failure.
             warn!("TSC freq not available. Snapshot cannot be loaded on a different CPU model.");
             None
         });

src/vmm/src/arch/x86_64/vm.rs

@@ -226,9 +226,7 @@ pub struct VmState {
     pub resource_allocator: ResourceAllocator,
     pitstate: kvm_pit_state2,
     clock: kvm_clock_data,
-    // TODO: rename this field to adopt inclusive language once Linux updates it, too.
     pic_master: kvm_irqchip,
-    // TODO: rename this field to adopt inclusive language once Linux updates it, too.
     pic_slave: kvm_irqchip,
     ioapic: kvm_irqchip,
 }

src/vmm/src/cpu_config/aarch64/custom_cpu_template.rs

@@ -22,7 +22,6 @@ impl GetCpuTemplate for Option<CpuTemplateType> {
             Some(template_type) => match template_type {
                 CpuTemplateType::Custom(template) => Ok(Cow::Borrowed(template)),
                 CpuTemplateType::Static(template) => match template {
-                    // TODO: Check if the CPU model is Neoverse-V1.
                     StaticCpuTemplate::V1N1 => Ok(Cow::Owned(v1n1::v1n1())),
                     other => Err(GetCpuTemplateError::InvalidStaticCpuTemplate(*other)),
                 },

src/vmm/src/cpu_config/x86_64/cpuid/intel/normalize.rs

@@ -312,8 +312,6 @@ pub enum DefaultBrandStringError {
 ///
 /// Never.
 // As we pass through host frequency, we require CPUID and thus `cfg(cpuid)`.
-// TODO: Use `split_array_ref`
-// (https://github.com/firecracker-microvm/firecracker/issues/3347)
 #[allow(clippy::indexing_slicing, clippy::arithmetic_side_effects)]
 #[inline]
 fn default_brand_string(

src/vmm/src/dumbo/pdu/ethernet.rs

@@ -15,8 +15,6 @@ const SRC_MAC_OFFSET: usize = 6;
 const ETHERTYPE_OFFSET: usize = 12;
 
 // We don't support 802.1Q tags.
-// TODO: support 802.1Q tags?! If so, don't forget to change the speculative_test_* functions
-// for ARP and IPv4.
 /// Payload offset in an ethernet frame
 pub const PAYLOAD_OFFSET: usize = 14;
 

src/vmm/src/dumbo/pdu/tcp.rs

@@ -88,9 +88,6 @@ pub enum TcpError {
     SliceTooShort,
 }
 
-// TODO: The implementation of TcpSegment is IPv4 specific in regard to checksum computation. Maybe
-// make it more generic at some point.
-
 /// Interprets the inner bytes as a TCP segment.
 #[derive(Debug)]
 pub struct TcpSegment<'a, T: 'a> {