bhyve entered ddb: Stopped at rdmsr

[Yuri Pankov]

Christian Barthel wrote:
> Hello,
> 
> I switched my notebook from a ThinkPad X230 to ThinkPad T480
> (each running 12.1).  I noticed that one of my OpenBSD (6.3)
> bhyve VMs is not booting anymore.  It stops with a debugger
> prompt:
> 
> acpi0: sleep states S5
> acpi0: tables DSDT FACP HPET APIC MCFG SPCR
> acpi0: wakeup devices
> acpitimer0 at acpi0: 3579545 Hz, 32 bits
> acpihpet0 at acpi0: 16777216 Hz
> acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
> cpu0 at mainbus0: apid 0 (boot processor)
> cpu0: Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz, 1992.07 MHz
> cpu0: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,MMX,FXSR,SSE,SSE2,SS,HTT,PBE,SSE3,PCLMUL,DTES64,DS-CPL,SSSE3,SDBG,FMA3,CX16,xTPR,PCID,SSE4.1,SSE4.2,MOVBE,POPCNT,AES,XSAVE,AVX,F16C,RDRAND,HV,NXE,PAGE1GB,LONG,LAHF,ABM,3DNOWP,ITSC,FSGSBASE,BMI1,AVX2,BMI2,ERMS,INVPCID,RDSEED,ARAT,MELTDOWN
> cpu0: 256KB 64b/line 8-way L2 cache
> rdmsr to register 0xc80 on vcpu 0
>                                   kernel: protection fault trap, code=0
> Stopped at      identifycpu+0x75c:      rdmsr
> ddb{0}>
> 
> 
> Does anyone know why / how to boot the VM?
> This VM runs fine on the X230 model but not on the T480.
> Other guests (FreeBSD, Ubuntu) run fine on the T480 model as
> well.

Are you using -w flag (Ignore accesses to unimplemented Model Specific 
Registers)?  At least, it seems to be required to boot Windows guest.