"ignore_msrs=1", is it a lie?

Operating Systems & Open Source Virtualization
1

Buongiorno experts

Many guides mention to use

kvm ignore_msrs=1

For m$$ 10 above 8xxx build.

I got m$$ 10 installed and running BEFORE stumbling upon the “ignore_msrs=1”. So I tried it with it without noticing any difference or dreaded B$OD.

What’s more after setting it, linux VMs don’t like that option as they spit RED warning in dmesg.

So my question is what exactly does ignore_msrs=1 fix on m$$ 10?
Do I needed?

I can run ms$ with real gpu, ungine at 60fps (without hardcore tweakings as many others) play videos at 1080p60, networking.

So my worry is whether the ignore_msrs=1 is more oftrepeated heresay or real.

Can somebody confirm this? In this 10.0.19041 build I haven’t experienced any B$ODs.

regards.

2

Is it a lie?

Short answer, no.

Long answer, it depends on your situation.

It won’t hurt you but it can help you.

Without seeing the errors in syslog, I can’t say if the error is a problem.

3

Please be more verbose.
What does it do precisely?

4

Some versions of Windows on some processors access hardware registers that aren’t actually defined for that processor. When they do this, KVM tells them that the instruction isn’t supported, which causes Windows to BSOD. The ignore_msrs option tells it not to do that, but to just ignore it instead.

You can tell whether you need to do this by checking your syslog, which will have lines like “unhandled rdmsr” or “unhandled wrmsr” if your version of Windows is doing it.

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