> ## Documentation Index
> Fetch the complete documentation index at: https://kernel.mvhcloud.com/llms.txt
> Use this file to discover all available pages before exploring further.
# MVH Kernel Diagnostics Shell Commands — Full Reference
> Reference for kernel diagnostics commands: meminfo, heapinfo, cpuinfo, features, irqstat, pagetable, dmesg, ps, devices, lspci, statics, and more.
MVH Kernel exposes a rich set of diagnostics commands that give you direct visibility into the physical memory allocator, the kernel heap, CPU capabilities, interrupt counters, page-table state, and the structured kernel log. You can run every command at the `mvh>` prompt without any arguments unless documented otherwise.
***
## meminfo
Print a detailed breakdown of physical memory from the PMM (Physical Memory Manager), including page-level counters and allocator statistics.
**Syntax**
```sh theme={null}
meminfo
```
**Output includes**
* `MemTotal` / `MemUsed` / `MemAvailable` — physical memory in KiB
* `Reserved` — pages reserved by the kernel image and hardware
* `HeapTotal` / `HeapUsed` — kernel heap in KiB
* `PageAlloc` / `PageFree` — total page allocation and free request counts
* `PageFailures` — count of failed page allocation attempts
* `PagePeak` — peak number of pages in use simultaneously
* `MappedPages` — current VMM-mapped page count
**Example**
```text theme={null}
mvh> meminfo
MemTotal: 130048 KiB
MemUsed: 12288 KiB
MemAvailable: 117760 KiB
Reserved: 2048 KiB
HeapTotal: 1024 KiB
HeapUsed: 128 KiB
PageAlloc: 3072
PageFree: 2944
PageFailures: 0
PagePeak: 3072 pages
MappedPages: 512
```
***
## free
Print a concise one-line memory summary covering both physical pages and heap allocations.
**Syntax**
```sh theme={null}
free
```
**Example**
```text theme={null}
mvh> free
total used free
Memory: 130048 KiB 12288 KiB 117760 KiB
Heap: 1024 KiB 128 KiB allocations: 47
```
***
## heapinfo
Print extended kernel heap statistics, including fragmentation information and error counters introduced in v1.1.2.
**Syntax**
```sh theme={null}
heapinfo
```
**Output includes**
| Field | Description |
| -------------------- | ------------------------------------------------------------------- |
| Heap total | Total heap size in bytes |
| Heap used | Bytes currently allocated |
| Heap free payload | Bytes available in free blocks |
| Largest free block | Size of the single largest free contiguous block |
| Blocks / free blocks | Total block count and count of free blocks |
| Allocations active | Live allocation count |
| Allocation failures | Count of `kmalloc` calls that returned null |
| Invalid frees | Count of `kfree` calls on invalid pointers (heap hardening, v1.1.2) |
| Integrity | `valid` if canary checks pass; `CORRUPTED` if the heap is damaged |
**Example**
```text theme={null}
mvh> heapinfo
Heap total: 1048576 bytes
Heap used: 131072 bytes
Heap free payload: 917504 bytes
Largest free block: 917504 bytes
Blocks/free blocks: 24/16
Allocations active: 47
Allocation failures: 0
Invalid frees: 0
Integrity: valid
```
***
## heaptest
Run the built-in heap allocator self-test. The test performs a series of allocations, writes, reads, and frees to verify that the allocator is functioning correctly.
**Syntax**
```sh theme={null}
heaptest
```
**Example**
```text theme={null}
mvh> heaptest
Heap self-test passed
```
***
## cpuinfo
Display extended CPU diagnostics. This command combines the CPU panel from `statics` with additional low-level fields added in v1.1.2, including TSC frequency, XSAVE area size, microcode version, and a hardware-RNG sample.
**Syntax**
```sh theme={null}
cpuinfo
```
**Output includes**
| Field | Description |
| ------------------------- | ---------------------------------------------------------------------------------------------------------------- |
| Vendor | CPU vendor string (e.g. `GenuineIntel`) |
| Model | CPU brand string |
| Family / Model / Stepping | CPUID topology identifiers |
| APIC ID | Local APIC identifier of the boot processor |
| Logical CPUs | Logical processor count from CPUID |
| Cache | L1D, L1I, L2, and L3 sizes in KiB |
| Temperature | Die temperature in °C from Intel DTS or AMD SMN/northbridge Tctl; `not available from this CPU/platform` in QEMU |
| TSC | Current TSC value (hex) and estimated TSC frequency in Hz |
| XSAVE area | XSAVE state area size in bytes |
| Microcode | Microcode revision (hex) if safely exposed; otherwise `not exposed safely by this platform` |
| Hardware RNG | A 64-bit sample from RDRAND if available |
CPU temperature reading requires Intel Digital Thermal Sensor MSRs, AMD Family 10h–16h northbridge Tctl, or AMD Family 17h–1Ah SMN Tctl. QEMU does not expose a usable thermal sensor, so the field reports `not available from this CPU/platform` in emulated environments.
**Example**
```text theme={null}
mvh> cpuinfo
+---------------------- CPU ----------------------+
| Architecture : x86_64
| Vendor : GenuineIntel
| Model : Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
| Logical CPUs : 12
| APIC ID : 0
| Family/Model : 6/158 stepping 10
| Local APIC : xAPIC enabled at 0xFEE00000000000000
| Temperature : not available from this CPU/platform
| Cache : L1D 32 KiB, L1I 32 KiB, L2 256 KiB, L3 12288 KiB
| CPU features : SSE SSE2 AVX AVX2
| Core status : state, not CPU usage
| Core 0 : RUNNING boot processor
| Core 1 : DETECTED not started
+-------------------------------------------------+
TSC: 0x000000012A4F8C30
TSC estimate: 2600000000 Hz
XSAVE area: 576 bytes
Microcode: not exposed safely by this platform
Hardware RNG: 0xA3F29D1C77BE4012
```
***
## features
List every CPUID capability flag and the active kernel protection settings. Each line shows `[yes]` or `[ no]` next to the feature name and a short description.
**Syntax**
```sh theme={null}
features
```
**Reported flags**
CPU hardware features: FPU, TSC, MSR, APIC, MMX, SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, AES, AVX, AVX2, AVX-512F, XSAVE, RDRAND, RDSEED, x2APIC, PAT, MTRR, NX, LONG MODE.
Kernel protection summary line reports: WP (supervisor write-protect), NX, SMEP, SMAP, UMIP.
**Example**
```text theme={null}
mvh> features
CPU hardware features
[yes] FPU - floating-point calculations
[yes] TSC - CPU timestamp counter
[yes] MSR - model-specific registers
[yes] APIC - advanced interrupt controller
[yes] SSE - streaming SIMD instructions
[yes] SSE2 - extended SIMD instructions
[ no] AVX-512F - 512-bit vector foundation
[yes] XSAVE - extended CPU state save/restore
[yes] NX - non-executable memory pages
...
Kernel protection: WP on, NX on, SMEP on, SMAP on, UMIP on
Additional detected cores require SMP startup support.
```
***
## irqstat
Print per-vector interrupt statistics. Counters are read atomically with interrupts briefly disabled to avoid a torn read.
**Syntax**
```sh theme={null}
irqstat
```
**Output includes**
| Field | Description |
| ---------------------- | --------------------------------------------- |
| Interrupt total | Cumulative interrupt count across all vectors |
| Timer IRQ0 / vector 32 | Count of PIT timer interrupts (100 Hz) |
| Spurious IRQs | Count of spurious 8259 PIC interrupts |
**Example**
```text theme={null}
mvh> irqstat
Interrupt total: 18432
Timer IRQ0/vector32: 18430
Spurious IRQs: 2
```
***
## pagetable
Query the VMM page table for a set of key virtual addresses and display their physical address mappings and page flags. The addresses probed are: `0x0` (null guard, expected unmapped), `0x1000`, the kernel end address, and the page-aligned kernel end address.
**Syntax**
```sh theme={null}
pagetable
```
**Example**
```text theme={null}
mvh> pagetable
VA 0x0000000000000000: unmapped
VA 0x0000000000001000: PA 0x0000000000001000 flags 0x8000000000000003
VA 0x000000000010E000: PA 0x000000000010E000 flags 0x8000000000000003
VA 0x000000000010F000: PA 0x000000000010F000 flags 0x8000000000000003
```
The null page at `VA 0x0` is unmapped by design — accessing it generates a page fault, which is captured by the exception handler.
***
## pagetest
Run the VMM (Virtual Memory Manager) self-test. The test exercises dynamic 4 KiB page mapping, unmapping, and lookup, and verifies that the null-page guard is correctly enforced.
**Syntax**
```sh theme={null}
pagetest
```
**Example**
```text theme={null}
mvh> pagetest
Page allocator self-test passed
```
***
## dmesg
Dump the kernel log ring buffer. The ring holds up to 16 KiB of structured, timestamped entries written by the kernel during boot and operation. Each entry includes a log level (INFO, WARN, ERROR) and an optional category tag.
**Syntax**
```sh theme={null}
dmesg
```
**Example**
```text theme={null}
mvh> dmesg
[ 0.00] INFO hardware abstraction layer initialized
[ 0.00] INFO physical memory manager initialized
[ 0.00] INFO paging protections and null guard initialized
[ 0.00] INFO kernel heap initialized
[ 0.00] INFO VFS mounted ramfs root
[ 0.00] INFO device manager initialized
```
***
## ps
List all registered kernel tasks. Each row shows the PID, priority, execution state, task name, and the PIT tick at which the task was created.
**Syntax**
```sh theme={null}
ps
```
**Task states:** `UNUSED`, `RUNNING`, `READY`, `SLEEPING`, `STOPPED`.
**Example**
```text theme={null}
mvh> ps
PID PRI STATE NAME
1 1 RUNNING kernel-shell
```
***
## devices
List all devices registered in the kernel device registry, showing the device ID, type, name, and online/offline status.
**Syntax**
```sh theme={null}
devices
```
**Example**
```text theme={null}
mvh> devices
ID TYPE STATE NAME
1 CPU ONLINE boot-cpu
2 INTERRUPT ONLINE 8259-pic
3 TIMER ONLINE 8254-pit
4 INPUT ONLINE ps2-keyboard
5 DISPLAY ONLINE vga-text
6 SERIAL ONLINE uart-com1
7 CLOCK ONLINE cmos-rtc
8 BUS ONLINE pci-config
9 FILESYSTEM ONLINE ramfs-root
```
***
## lspci
Scan the PCI configuration space and list every discovered device with its bus/slot/function address, vendor and device IDs, and a class name.
**Syntax**
```sh theme={null}
lspci
```
**Example**
```text theme={null}
mvh> lspci
0:0.0 8086:1237 Host Bridge
0:1.0 8086:7000 ISA Bridge
0:1.1 8086:7010 IDE Controller
0:2.0 1234:1111 VGA Compatible Controller
```
If no PCI devices are found, the shell prints `No PCI devices found.`
***
## drivers
List all drivers compiled into the kernel and their responsibilities.
**Syntax**
```sh theme={null}
drivers
```
**Example**
```text theme={null}
mvh> drivers
Loaded kernel drivers
vga-text-cursor display and hardware cursor
ps2-keyboard-en-us keyboard, Shift, Caps, Ctrl
serial-uart-16550 COM1 debug output
x86-cpuid CPU detection
cmos-rtc real-time clock
pci-config PCI device discovery
x86-idt-pic interrupt controller
x86-exceptions CPU exception handling
pit-8254 system timer
ramfs volatile filesystem
device-manager kernel device registry
```
***
## statics
Open the full-screen live system monitor. The monitor displays a RAM usage bar with used/free/total figures in MiB, and a per-core CPU status panel listing each logical processor's execution state. Press **Q** or **Ctrl+C** to exit and return to the `mvh>` prompt.
**Syntax**
```sh theme={null}
statics
```
Use `statics` to get a quick overview of memory pressure and CPU topology. The panel shows actual execution state rather than simulated usage bars, so the values are accurate.
***
## paniccodes
List all stable kernel panic codes and their meanings. These codes appear in the top line of a kernel panic dump on both VGA and the serial console, making them easy to identify in crash logs.
**Syntax**
```sh theme={null}
paniccodes
```
**Example**
```text theme={null}
mvh> paniccodes
MVH panic code format
MVH-KERNEL-0001 explicit kernel panic
MVH-EX-00 divide error
MVH-EX-06 invalid opcode
MVH-EX-08 double fault
MVH-EX-0D general protection fault
MVH-EX-0E page fault
MVH-EX-12 machine check
MVH-EX-15 control protection
Crash output includes vector, decoded error flags, CR0-CR4, registers and stack trace.
```
A crash dump includes the panic code, the exception vector, decoded hardware error-code flags, control registers (CR0–CR4), all general-purpose registers (RAX–R15, RIP, RFLAGS), and a bounded frame-pointer stack trace.