Print MicrovmState from vmstate file of snapshot

CHANGELOG.md

@@ -14,6 +14,11 @@
   each individual block device will emit metrics under the label `"block_{drive_id}"`.
   E.g. the associated metrics for the endpoint `"/drives/{drive_id}"` will
   be available under `"block_drive_id"` in the metrics json object.
+- [#4205](https://github.com/firecracker-microvm/firecracker/pull/4205):
+  Added a new `vm-state` subcommand to `info-vmstate` command in the
+  `snapshot-editor` tool to print MicrovmState of vmstate snapshot file in
+  a readable format. Also made the `vcpu-states` subcommand available on
+  x86_64.
 
 ### Changed
 

docs/snapshotting/snapshot-editor.md

@@ -16,104 +16,125 @@ Firecracker snapshot consists of 2 files:
 
 #### `rebase` subcommand
 
-This command is used to merge a `diff` snapshot memory file on
-top of a base memory file.
-
-**Note**
-You can also use `rebase-snap` (deprecated) tool for this.
-
-Arguments:
-
-- `MEMORY_PATH` - path to the `memory` file
-- `DIFF_PATH` - path to the `diff` file
-
-Usage:
-
-```bash
-snapshot-editor edit-memory rebase \
-     --memory-path <MEMORY_PATH> \
-     --diff-path <DIFF_PATH>
-```
-
-Example:
-
-```bash
-snapshot-editor edit-memory rebase \
-     --memory-path ./memory_file \
-     --diff-path ./diff_file
-```
+> This command is used to merge a `diff` snapshot memory file on
+> top of a base memory file.
+>
+> **Note**
+> You can also use `rebase-snap` (deprecated) tool for this.
+>
+> Arguments:
+>
+> - `MEMORY_PATH` - path to the `memory` file
+> - `DIFF_PATH` - path to the `diff` file
+>
+> Usage:
+>
+> ```bash
+> snapshot-editor edit-memory rebase \
+>      --memory-path <MEMORY_PATH> \
+>      --diff-path <DIFF_PATH>
+> ```
+>
+> Example:
+>
+> ```bash
+> snapshot-editor edit-memory rebase \
+>      --memory-path ./memory_file \
+>      --diff-path ./diff_file
+> ```
 
 ### `edit-vmstate` command
 
 #### `remove-regs` subcommand (aarch64 only)
 
-This command is used to remove specified registers from vcpu states inside
-vmstate snapshot file.
-
-Arguments:
-
-- `VMSTATE_PATH` - path to the `vmstate` file
-- `OUTPUT_PATH` - path to the file where the output will be placed
-- `[REGS]` - set of u32 values representing registers ids as they are defined
-  in KVM. Can be both in decimal and in hex formats.
-
-Usage:
-
-```bash
-snapshot-editor edit-vmstate remove-regs \
-    --vmstate-path <VMSTATE_PATH> \
-    --output-path <OUTPUT_PATH> \
-    [REGS]...
-```
-
-Example:
-
-```bash
-./snapshot-editor edit-vmstate remove-regs \
-    --vmstate-path ./vmstate_file \
-    --output-path ./new_vmstate_file \
-    0x1 0x2
-```
+> This command is used to remove specified registers from vcpu states inside
+> vmstate snapshot file.
+>
+> Arguments:
+>
+> - `VMSTATE_PATH` - path to the `vmstate` file
+> - `OUTPUT_PATH` - path to the file where the output will be placed
+> - `[REGS]` - set of u32 values representing registers ids as they are defined
+>   in KVM. Can be both in decimal and in hex formats.
+>
+> Usage:
+>
+> ```bash
+> snapshot-editor edit-vmstate remove-regs \
+>     --vmstate-path <VMSTATE_PATH> \
+>     --output-path <OUTPUT_PATH> \
+>     [REGS]...
+> ```
+>
+> Example:
+>
+> ```bash
+> ./snapshot-editor edit-vmstate remove-regs \
+>     --vmstate-path ./vmstate_file \
+>     --output-path ./new_vmstate_file \
+>     0x1 0x2
+> ```
 
 ### `info-vmstate` command
 
 #### `version` subcommand
 
-This command is used to print version of the provided
-vmstate file.
-
-Arguments:
-
-- `VMSTATE_PATH` - path to the `vmstate` file
-
-Usage:
-
-```bash
-snapshot-editor info-vmstate version --vmstate-path <VMSTATE_PATH>
-```
-
-Example:
-
-```bash
-./snapshot-editor info-vmstate version --vmstate-path ./vmstate_file
-```
-
-#### `vcpu-states` subcommand (aarch64 only)
-
-This command is used to print the vCPU states inside vmstate snapshot file.
-
-Arguments:
-
-- `VMSTATE_PATH` - path to the `vmstate` file
-
-Usage:
-
-```bash
-snapshot-editor info-vmstate vcpu-states --vmstate-path <VMSTATE_PATH>
-```
-
-Example:
-
-```bash
-./snapshot-editor info-vmstate vcpu-states --vmstate-path ./vmstate_file
-```
+> This command is used to print version of the provided
+> vmstate file.
+>
+> Arguments:
+>
+> - `VMSTATE_PATH` - path to the `vmstate` file
+>
+> Usage:
+>
+> ```bash
+> snapshot-editor info-vmstate version --vmstate-path <VMSTATE_PATH>
+> ```
+>
+> Example:
+>
+> ```bash
+> ./snapshot-editor info-vmstate version --vmstate-path ./vmstate_file
+> ```
+
+#### `vcpu-states` subcommand
+
+> This command is used to print the vCPU states inside vmstate snapshot file.
+>
+> Arguments:
+>
+> - `VMSTATE_PATH` - path to the `vmstate` file
+>
+> Usage:
+>
+> ```bash
+> snapshot-editor info-vmstate vcpu-states --vmstate-path <VMSTATE_PATH>
+> ```
+>
+> Example:
+>
+> ```bash
+> ./snapshot-editor info-vmstate vcpu-states --vmstate-path ./vmstate_file
+> ```
+
+#### `vm-state` subcommand
+
+> This command is used to print the vmstate of snapshot file in
+> readable format thus, making it easier to compare vmstate of 2 snapshots.
+>
+> Arguments:
+>
+> - `VMSTATE_PATH` - path to the `vmstate` file
+>
+> Usage:
+>
+> ```bash
+> snapshot-editor info-vmstate vm-state --vmstate-path <VMSTATE_PATH>
+> ```
+>
+> Example:
+>
+> ```bash
+> ./snapshot-editor info-vmstate vm-state --vmstate-path ./vmstate_file
+> ```

src/snapshot-editor/src/info.rs

@@ -26,21 +26,26 @@
         vmstate_path: PathBuf,
     },
     /// Print info about vcpu states.
-    #[cfg(target_arch = "aarch64")]
     VcpuStates {
         /// Path to the vmstate file.
         #[arg(short, long)]
         vmstate_path: PathBuf,
     },
+    /// Print readable MicroVM state.
+    VmState {
+        /// Path to the vmstate file.
+        #[arg(short, long)]
+        vmstate_path: PathBuf,
+    },
 }
 
 pub fn info_vmstate_command(command: InfoVmStateSubCommand) -> Result<(), InfoVmStateError> {
     match command {
         InfoVmStateSubCommand::Version { vmstate_path } => info(&vmstate_path, info_version)?,
-        #[cfg(target_arch = "aarch64")]
         InfoVmStateSubCommand::VcpuStates { vmstate_path } => {
             info(&vmstate_path, info_vcpu_states)?
         }
+        InfoVmStateSubCommand::VmState { vmstate_path } => info(&vmstate_path, info_vmstate)?,
     }
     Ok(())
 }
@@ -67,23 +72,15 @@
     }
 }
 
-#[cfg(target_arch = "aarch64")]
 fn info_vcpu_states(state: &MicrovmState, _: u16) -> Result<(), InfoVmStateError> {
     for (i, state) in state.vcpu_states.iter().enumerate() {
         println!("vcpu {i}:");
-        println!("kvm_mp_state: {:#x}", state.mp_state.mp_state);
-        println!("mpidr: {:#x}", state.mpidr);
-        for reg in state.regs.iter() {
-            println!(
-                "{:#x} 0x{}",
-                reg.id,
-                reg.as_slice()
-                    .iter()
-                    .rev()
-                    .map(|b| format!("{b:x}"))
-                    .collect::<String>()
-            );
-        }
+        println!("{state:#?}");
     }
     Ok(())
 }
+
+fn info_vmstate(vmstate: &MicrovmState, _version: u16) -> Result<(), InfoVmStateError> {
+    println!("{vmstate:#?}");
+    Ok(())
+}

src/vmm/src/vstate/vcpu/aarch64.rs

@@ -5,6 +5,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the THIRD-PARTY file.
 
+use std::fmt::Debug;
+
 use kvm_bindings::*;
 use kvm_ioctls::*;
 use versionize::{VersionMap, Versionize, VersionizeError, VersionizeResult};
@@ -250,7 +252,7 @@
 }
 
 /// Structure holding VCPU kvm state.
-#[derive(Debug, Default, Clone, Versionize)]
+#[derive(Default, Clone, Versionize)]
 pub struct VcpuState {
     /// Multiprocessing state.
     pub mp_state: kvm_bindings::kvm_mp_state,
@@ -271,6 +273,26 @@
     pub kvi: Option<kvm_bindings::kvm_vcpu_init>,
 }
 
+impl Debug for VcpuState {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        writeln!(f, "kvm_mp_state: {:#x}", self.mp_state.mp_state)?;
+        writeln!(f, "mpidr: {:#x}", self.mpidr)?;
+        for reg in self.regs.iter() {
+            writeln!(
+                f,
+                "{:#x} 0x{}",
+                reg.id,
+                reg.as_slice()
+                    .iter()
+                    .rev()
+                    .map(|b| format!("{b:x}"))
+                    .collect::<String>()
+            )?;
+        }
+        Ok(())
+    }
+}
+
 impl VcpuState {
     fn default_old_regs(_: u16) -> Vec<Aarch64RegisterOld> {
         Vec::default()

src/vmm/src/vstate/vcpu/x86_64.rs

@@ -6,6 +6,7 @@
 // found in the THIRD-PARTY file.
 
 use std::collections::{HashMap, HashSet};
+use std::fmt::Debug;
 
 use kvm_bindings::{
     kvm_debugregs, kvm_lapic_state, kvm_mp_state, kvm_regs, kvm_sregs, kvm_vcpu_events, kvm_xcrs,
@@ -540,7 +541,7 @@
     }
 }
 
-#[derive(Debug, Clone, Versionize)]
+#[derive(Clone, Versionize)]
 /// Structure holding VCPU kvm state.
 // NOTICE: Any changes to this structure require a snapshot version bump.
 pub struct VcpuState {
@@ -573,6 +574,30 @@
     pub tsc_khz: Option<u32>,
 }
 
+impl Debug for VcpuState {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let mut debug_kvm_regs: Vec<kvm_bindings::kvm_msrs> = Vec::new();
+        for kvm_msrs in self.saved_msrs.iter() {
+            debug_kvm_regs = kvm_msrs.clone().into_raw();
+            debug_kvm_regs.sort_by_key(|msr| (msr.nmsrs, msr.pad));
+        }
+        f.debug_struct("VcpuState")
+            .field("cpuid", &self.cpuid)
+            .field("msrs", &self.msrs)
+            .field("saved_msrs", &debug_kvm_regs)
+            .field("debug_regs", &self.debug_regs)
+            .field("lapic", &self.lapic)
+            .field("mp_state", &self.mp_state)
+            .field("regs", &self.regs)
+            .field("sregs", &self.sregs)
+            .field("vcpu_events", &self.vcpu_events)
+            .field("xcrs", &self.xcrs)
+            .field("xsave", &self.xsave)
+            .field("tsc_khz", &self.tsc_khz)
+            .finish()
+    }
+}
+
 impl VcpuState {
     fn default_tsc_khz(_: u16) -> Option<u32> {
         warn!("CPU TSC freq not found in snapshot");