Trying to make a happy kernel for an i7 920 with KVM

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

I think I get it. I thought you were asking something else.

Right now, I have the log entry and nothing else. I haven't tried KVM yet. I'm trying to have my ducks in a row before diving in. I'm reasonably experienced with VMware on Linux, Mac and Windows, and with Parallels on Mac. So I'm a KVM newbie.

I'm just going through the Gentoo KVM HOWTO right now, and discovered that qemu-kvm is masked by ~amd64. I now suddenly wonder why, and if it's always masked or if something bad just happened.

I was under the impression that KVM was a mature product. I unmasked it for now, but I would like to have some level of confidence that when I have commercial software licenses on KVM I won't be stuck with dead software.

Thanks.

cach0rr0 · Posted: Sat Oct 16, 2010 7:56 am Post subject:

it's perfectly stable. It's just not officially perfectly stable.

If you have your /dev/kvm you're fine. And really, do a 1GB qcow2 image, boot qemu-kvm from a minimal iso (preferably sysrescuecd!), see if it works. There's no real harm in it, and that's a more than adequate test. If that works, nothing else you could potentially do should be problematic.

aCOSwt · Posted: Sat Oct 16, 2010 8:39 am Post subject:

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

I don't have any MTRR setting in my bios. I don't have anything with a setting of continuous or discrete either.

And I did find a new issue with VT-d settings being turned on: The system will not run the nvidia X driver. I get a frozen screen after X starts, and it does not come back.

I changed the sata mode from PCI to AHCP (sorry if the four letter acronyms are wrong, I'm working from memory here) but still nothing shows up.

Is there some other name by which MTRR might be referenced? Nearly everything is either Enabled or Disabled, and if it's not a legacy feature it seems to be enabled.

I'm not messing with RAM timings or processor speed settings just on a lark.

I'll look through the nvidia guide and see if I can find something interesting.

Thanks.

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

However, I see my kernel has a setting for MTRR and it's set to "continuous". I obviously missed some things in here. I looked at it a month or 3 ago and I evidently did it sleeping.

Thanks.

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

OK I think what happened is when I started asking for help, I just took a bare seed from Pappy's site, then did what you guys said. There are settings turned off that I am positive I turned on last time.

No harm no foul, I stopped paying attention when I started this thread. I'll save the existing config so I can revert and start going from there.

I'll take it from here for a bit, the only thing I really need is info on this VT-d setting and a potential unofficial BIOS upgrade that may or may not actually be floating around somewhere.

My kernel is definitely MUCH happier than it was when I asked for help.

Thanks.

pappy_mcfae · Posted: Sun Oct 17, 2010 6:21 am Post subject:

Always glad to help...and to see others out there in the thick of it as well. Happy Gentooing!

Cheers,
Pappy
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1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

Trying to figure out what my MTRR kernel values should be.

I have this in my current kernel:
CONFIG_MTRR=y
CONFIG_MTRR_SANITIZER=y
CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT=0
CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT=1

I can't find documentation on what the last 2 should be.

Any advice, or do I just start experimenting? I can't even really tell what the possible options are.

Based on what I found in the kernel source, I'm guessing these values:
CONFIG_MTRR=y
CONFIG_MTRR_SANITIZER=y
CONFIG_MTRR_SANITIZER_ENABLE_DEFAULT=1
CONFIG_MTRR_SANITIZER_SPARE_REG_NR_DEFAULT=4

If you never hear from me again, I've torn a hole in the space-time continuum and will probably come back out of the black hole at the other end of the universe.

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

I think that did exactly jack. My /proc/mtrr is no different.

glxgears is even slower.

Here's the pertinent part of dmesg, only what I think is "new" mtrr related information which is impenetrable to me.

aCOSwt · Posted: Wed Oct 20, 2010 7:53 am Post subject:

1clue · Advocate Joined: 05 Feb 2006 Posts: 2569

<satire>
We may have stumbled upon a paradoxical paradigm of Roddenberry-esqe scale!

Indeed, not even Wells himself explored the possibilities of time travel and space travel simultaneously.

It seems as though we're stuck with rank amateurs such as Einstein and Clarke to guide us through this maze of confusion.
</satire>