Black screen when starting Ubuntu 20.04 on Windows 10 host

[vc019]

Hi All,

I am having issues with my Ubuntu 20.04 image and it seems to be hanging whenever I start. This has recently started up. Not sure what the issue and thought all the good folks here could help me. I have attached the logs to the post. Please let me know if something can be done.

I am using the latest virtual box software.

Regards

V

[scottgus1]

The log shows no Hyper-V interference, good.

The log ends with this, just after booting from the guest disk:

00:00:14.440217 PIT: mode=2 count=0x12a5 (4773) - 249.98 Hz (ch=0)
00:00:14.464732 IEM: rdmsr(0x4e) -> #GP(0)
00:00:14.574485 PIT: mode=0 count=0x10000 (65536) - 18.20 Hz (ch=0)
00:00:14.576337 IEM: rdmsr(0x4e) -> #GP(0)
00:00:14.580140 IEM: rdmsr(0x4e) -> #GP(0)
00:00:14.583879 IEM: rdmsr(0x4e) -> #GP(0)
00:00:14.599071 IEM: rdmsr(0x4e) -> #GP(0)
00:00:14.602650 IEM: rdmsr(0x4e) -> #GP(0)

I think the IEM line is an attempt to adjust the appearance of the host processor to the guest OS. The repeats seem to indicate that something isn;t sticking as it should. If our hex-whisperer 'fth0' comes along you'll probably get a complete breakdown of what it means.

One thing I do see is your CPU has 6 hypertreaded cores, and the guest has 6 processors. Hyperthreads don't help Virtualbox, so your guest might starve the host. Try 2 guest processors.

I suggest you try to make a new Ubuntu 2004 guest and see if it runs the same or better.

[vc019]

Thanks Scott,

Moved the number of processors to 2 and it has not changed the result. The new log is attached. What I have also seen is that the entire virtualbox application hangs. The application starts responding after the ubuntu window is closed.
Created another image today in the afternoon and it seems to be working fine without issue.

Regards

Vipin

[fth0]

you'll probably get a complete breakdown of what it means.

Not this time. But the expected next log messages would be coming from the paravirtualization interface, and that trace leads to:

00:00:03.260183 [/GIM/] (level 1)
00:00:03.260183   Provider <string>  = "HyperV" (cb=7)

In the VM configuration, go to Settings > System > Acceleration. If Paravirtualization Interface isn't set to Default, set it to Default, otherwise set it to KVM. This is probably your real problem.

00:00:03.612025 AssertLogRel F:\tinderbox\win-6.1\src\VBox\Devices\PC\DevFwCommon.cpp(875) int __cdecl FwCommonPlantDMITable(struct PDMDEVINSR3 *,unsigned char *,unsigned int,const union RTUUID *,struct CFGMNODE *,unsigned short,unsigned short *,unsigned short *,bool): <NULL>
00:00:03.612033 DMI: RAM size 0x800000000 too big for one type-17 descriptor, clipping to 0x7fff00000

Reduce the provided RAM to 31 GB (or 32 GB - 1 MB = 32767 MB), to avoid potential problems indicated by those log messages.

[vc019]

Cheers fth0 & scottgus1.

The issue is now resolved.

Happy days!

Regards

[fth0]

The issue is now resolved.

You could reveal what solved it, and which Paravirtualization Interface was configured.

[vc019]

fth0,

Thanks for reminding me.

So the change which did the trick was changing the following
Goto VM settings Settings->System->Acceleration

Changed Paravirtualization Interface from Hyper-V to default
Hardware Virtualization was kept unchanged at enabled.