Dump MSR registers to check if they are sane for enabling SEV-SNP

snp_msr_check.py

#!/usr/bin/env python

import subprocess
from collections import OrderedDict

def check_msr():
    out = subprocess.run(["which", "rdmsr"], capture_output=True)
    if out.stdout == b'':
        subprocess.run(["sudo", "apt", "update"])
        subprocess.run(["sudo", "apt", "install", "-y", "msr-tools"])

def insmod_msr():
    out = subprocess.run(["lsmod"], capture_output=True)
    if out.returncode == 0:
        lsmod_out = out.stdout.decode('utf-8').splitlines()
        modules_list = [m.split(' ')[0] for m in lsmod_out]
        # print(modules_list)
        if "msr" not in modules_list:
            subprocess.run(["sudo", "modprobe", "msr"])
 
def dump_values():
    amd_msrs = OrderedDict()
    # Syscfg
    amd_msrs["SYSCFG"] = "0xC0010010"

    # IORR
    amd_msrs["IORRBase0"] = "0xC0010016"
    amd_msrs["IORRMask0"] = "0xC0010017"
    amd_msrs["IORRBase1"] = "0xC0010018"
    amd_msrs["IORRMask0"] = "0xC0010019"

    amd_msrs["TOP_MEM"] = "0xC001001A"
    amd_msrs["TOP_MEM2"] = "0xC001001D"
    amd_msrs["VM_HSAVE_PA"] = "0xC0010117"

    # Variable-Range MTRRs
    amd_msrs["MTRRphysBase0"] = "0x200"
    amd_msrs["MTRRphysMask0"] = "0x201"
    amd_msrs["MTRRphysBase1"] = "0x202"
    amd_msrs["MTRRphysMask1"] = "0x203"
    amd_msrs["MTRRphysBase2"] = "0x204"
    amd_msrs["MTRRphysMask2"] = "0x205"
    amd_msrs["MTRRphysBase3"] = "0x206"
    amd_msrs["MTRRphysMask3"] = "0x207"
    amd_msrs["MTRRphysBase4"] = "0x208"
    amd_msrs["MTRRphysMask4"] = "0x209"
    amd_msrs["MTRRphysBase5"] = "0x20a"
    amd_msrs["MTRRphysMask5"] = "0x20b"
    amd_msrs["MTRRphysBase6"] = "0x20c"
    amd_msrs["MTRRphysMask6"] = "0x20d"
    amd_msrs["MTRRphysBase7"] = "0x20e"
    amd_msrs["MTRRphysMask7"] = "0x20f"

    # Fixed-Range MTRRs
    amd_msrs["MTRRfix64K_00000"] = "0x250"
    amd_msrs["MTRRfix16K_80000"] = "0x258"
    amd_msrs["MTRRfix16K_A0000"] = "0x259"
    amd_msrs["MTRRfix4K_C0000"] = "0x268"
    amd_msrs["MTRRfix4K_C8000"] = "0x269"
    amd_msrs["MTRRfix4K_D0000"] = "0x26A"
    amd_msrs["MTRRfix4K_D8000"] = "0x26B"
    amd_msrs["MTRRfix4K_E0000"] = "0x26C"
    amd_msrs["MTRRfix4K_E8000"] = "0x26D"
    amd_msrs["MTRRfix4K_F0000"] = "0x26E"
    amd_msrs["MTRRfix4K_F8000"] = "0x26F"

    # Default-Range MTRRs
    amd_msrs["MTRRdefType"] = "0x2FF"
 
    amd_msrs["MTRRcap"] = "0x00FE"

    print("Name, address, set(values)")
    for (k, v) in amd_msrs.items():
        rdmsr_out_all = subprocess.run(["sudo", "rdmsr", "-a", v], capture_output=True)
        rdmsr_out = set(rdmsr_out_all.stdout.decode('utf-8').splitlines())
        print(f'{k}, {v}, {rdmsr_out}')
        
if __name__ == '__main__':
    check_msr()
    insmod_msr()
    dump_values()