all messages for Guix-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
* bug#27636: /dev/kvm went missing on i686, Linux 4.12
@ 2017-07-10  5:40 Ricardo Wurmus
  2017-07-10 15:52 ` Leo Famulari
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Ricardo Wurmus @ 2017-07-10  5:40 UTC (permalink / raw)
  To: 27636

Since the update to Linux 4.12 my i686 machine no longer has /dev/kvm.
I ran “modprobe kvm” successfully, and “lsmod” shows “kvm”, but the
device node does not exist.

Running “modprobe kvm-intel” prints:

    modprobe: ERROR: could not insert 'kvm_intel': Input/output error

-- 
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2017-07-10  5:40 bug#27636: /dev/kvm went missing on i686, Linux 4.12 Ricardo Wurmus
@ 2017-07-10 15:52 ` Leo Famulari
  2017-07-10 17:29 ` Mark H Weaver
  2019-06-23  4:13 ` Chris Marusich
  2 siblings, 0 replies; 8+ messages in thread
From: Leo Famulari @ 2017-07-10 15:52 UTC (permalink / raw)
  To: Ricardo Wurmus; +Cc: 27636

[-- Attachment #1: Type: text/plain, Size: 470 bytes --]

On Mon, Jul 10, 2017 at 07:40:51AM +0200, Ricardo Wurmus wrote:
> Since the update to Linux 4.12 my i686 machine no longer has /dev/kvm.
> I ran “modprobe kvm” successfully, and “lsmod” shows “kvm”, but the
> device node does not exist.
> 
> Running “modprobe kvm-intel” prints:
> 
>     modprobe: ERROR: could not insert 'kvm_intel': Input/output error

I see the same thing on x86_64, but also with older kernels (at least
the 4.11 series).

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2017-07-10  5:40 bug#27636: /dev/kvm went missing on i686, Linux 4.12 Ricardo Wurmus
  2017-07-10 15:52 ` Leo Famulari
@ 2017-07-10 17:29 ` Mark H Weaver
  2017-07-17 20:06   ` Ricardo Wurmus
  2019-06-23  4:13 ` Chris Marusich
  2 siblings, 1 reply; 8+ messages in thread
From: Mark H Weaver @ 2017-07-10 17:29 UTC (permalink / raw)
  To: Ricardo Wurmus; +Cc: 27636

Ricardo Wurmus <rekado@elephly.net> writes:

> Since the update to Linux 4.12 my i686 machine no longer has /dev/kvm.
> I ran “modprobe kvm” successfully, and “lsmod” shows “kvm”, but the
> device node does not exist.
>
> Running “modprobe kvm-intel” prints:
>
>     modprobe: ERROR: could not insert 'kvm_intel': Input/output error

Does the kernel message buffer mention anything about "kvm" or "KVM"?

  dmesg | grep -i kvm

      Mark

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2017-07-10 17:29 ` Mark H Weaver
@ 2017-07-17 20:06   ` Ricardo Wurmus
  2017-07-18 20:02     ` Mark H Weaver
  0 siblings, 1 reply; 8+ messages in thread
From: Ricardo Wurmus @ 2017-07-17 20:06 UTC (permalink / raw)
  To: Mark H Weaver; +Cc: 27636


Mark H Weaver <mhw@netris.org> writes:

> Ricardo Wurmus <rekado@elephly.net> writes:
>
>> Since the update to Linux 4.12 my i686 machine no longer has /dev/kvm.
>> I ran “modprobe kvm” successfully, and “lsmod” shows “kvm”, but the
>> device node does not exist.
>>
>> Running “modprobe kvm-intel” prints:
>>
>>     modprobe: ERROR: could not insert 'kvm_intel': Input/output error
>
> Does the kernel message buffer mention anything about "kvm" or "KVM"?
>
>   dmesg | grep -i kvm

No, there is no mention of “kvm” or “KVM” in the kernel messages.

--
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2017-07-17 20:06   ` Ricardo Wurmus
@ 2017-07-18 20:02     ` Mark H Weaver
  2017-07-18 20:09       ` Ricardo Wurmus
  0 siblings, 1 reply; 8+ messages in thread
From: Mark H Weaver @ 2017-07-18 20:02 UTC (permalink / raw)
  To: Ricardo Wurmus; +Cc: 27636

Ricardo Wurmus <rekado@elephly.net> writes:

> Mark H Weaver <mhw@netris.org> writes:
>
>> Ricardo Wurmus <rekado@elephly.net> writes:
>>
>>> Since the update to Linux 4.12 my i686 machine no longer has /dev/kvm.
>>> I ran “modprobe kvm” successfully, and “lsmod” shows “kvm”, but the
>>> device node does not exist.
>>>
>>> Running “modprobe kvm-intel” prints:
>>>
>>>     modprobe: ERROR: could not insert 'kvm_intel': Input/output error
>>
>> Does the kernel message buffer mention anything about "kvm" or "KVM"?
>>
>>   dmesg | grep -i kvm
>
> No, there is no mention of “kvm” or “KVM” in the kernel messages.

When you looked for "kvm" or "KVM", did your kernel message buffer still
include the initial boot messages?  The kernel message buffer is of a
fixed size, so eventually the early messages are lost.

The reason I ask is because I did some web searches looking for other
people with the same problem, and what I found was that there was
typically a kernel message at boot time explaining why KVM was disabled.

In my case, on my Thinkpad X200 (which I'm sorry to say is running a
proprietary BIOS for now, because I had to replace the motherboard
recently and haven't yet gotten around to buying the needed clip to
reflash) I see the message "kvm: disabled by bios".

I'm fairly sure that I've seen /dev/kvm on this machine in the past.  It
might be that in earlier versions of Linux, /dev/kvm was created even
when it couldn't be used, and now it's created only conditionally, but
that's only a guess.

I haven't made any changes to the kernel configuration except to add
support for new modules and features as they become available, and as
far as I can see, the relevant KVM options are enabled just as they have
been in the past.

If all else fails, you could try using the 4.9 or 4.4 kernel and see if
that makes any difference.

       Mark

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2017-07-18 20:02     ` Mark H Weaver
@ 2017-07-18 20:09       ` Ricardo Wurmus
  0 siblings, 0 replies; 8+ messages in thread
From: Ricardo Wurmus @ 2017-07-18 20:09 UTC (permalink / raw)
  To: Mark H Weaver; +Cc: 27636


Mark H Weaver <mhw@netris.org> writes:

> When you looked for "kvm" or "KVM", did your kernel message buffer still
> include the initial boot messages?  The kernel message buffer is of a
> fixed size, so eventually the early messages are lost.

I ran it immediately after booting 4.12.

> I'm fairly sure that I've seen /dev/kvm on this machine in the past.  It
> might be that in earlier versions of Linux, /dev/kvm was created even
> when it couldn't be used, and now it's created only conditionally, but
> that's only a guess.

I have seen it in the past as well.  It is only with 4.12 that /dev/kvm
is gone.  I have installed 4.9 on this machine and /dev/kvm exists.

-- 
Ricardo

GPG: BCA6 89B6 3655 3801 C3C6  2150 197A 5888 235F ACAC
https://elephly.net

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2017-07-10  5:40 bug#27636: /dev/kvm went missing on i686, Linux 4.12 Ricardo Wurmus
  2017-07-10 15:52 ` Leo Famulari
  2017-07-10 17:29 ` Mark H Weaver
@ 2019-06-23  4:13 ` Chris Marusich
  2020-03-22 20:34   ` Leo Famulari
  2 siblings, 1 reply; 8+ messages in thread
From: Chris Marusich @ 2019-06-23  4:13 UTC (permalink / raw)
  To: Ricardo Wurmus; +Cc: 27636

[-- Attachment #1: Type: text/plain, Size: 407 bytes --]

Ricardo Wurmus <rekado@elephly.net> writes:

> Since the update to Linux 4.12 my i686 machine no longer has /dev/kvm.
> I ran “modprobe kvm” successfully, and “lsmod” shows “kvm”, but the
> device node does not exist.
>
> Running “modprobe kvm-intel” prints:
>
>     modprobe: ERROR: could not insert 'kvm_intel': Input/output error

Is this still an issue for you?

-- 
Chris

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

^ permalink raw reply	[flat|nested] 8+ messages in thread

* bug#27636: /dev/kvm went missing on i686, Linux 4.12
  2019-06-23  4:13 ` Chris Marusich
@ 2020-03-22 20:34   ` Leo Famulari
  0 siblings, 0 replies; 8+ messages in thread
From: Leo Famulari @ 2020-03-22 20:34 UTC (permalink / raw)
  To: Chris Marusich; +Cc: 27636-done

On Sat, Jun 22, 2019 at 09:13:37PM -0700, Chris Marusich wrote:
> Is this still an issue for you?

Closing due to lack of interest.

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2020-03-22 20:35 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2017-07-10  5:40 bug#27636: /dev/kvm went missing on i686, Linux 4.12 Ricardo Wurmus
2017-07-10 15:52 ` Leo Famulari
2017-07-10 17:29 ` Mark H Weaver
2017-07-17 20:06   ` Ricardo Wurmus
2017-07-18 20:02     ` Mark H Weaver
2017-07-18 20:09       ` Ricardo Wurmus
2019-06-23  4:13 ` Chris Marusich
2020-03-22 20:34   ` Leo Famulari

Code repositories for project(s) associated with this external index

	https://git.savannah.gnu.org/cgit/guix.git

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.