On 07/05/2011 12:56 PM, Sasha Levin wrote:
Please note that I don't have access to the hardware in question, this
was done over IRC.
I understand that. Can you get in contact with the reporter again?
Here are the steps taken in debugging this issue:
1. Looking at the dmesg ( http://pastebin.com/eM7bDY8r ) we saw that
when trying to load the kvm module, the following error shows up: 'kvm:
enabling virtualization on CPU0 failed'.
2. We went through the lsmod output (unfortunately I don't have the link
as it's gone from my IRC buffer) and didn't see any modules belonging to
other hypervisors.
3. At that point, looking at the code - we figured that a set SVM flag
is the possible culprit since it's the only code path which fails
loading the module with that error message without printing anything
else.
4. Installed msr-tools and injected the msr module so that we could read
msr values from userspace.
5. Ran 'rdmsr 0xc0000080' to read the extended feature register. The
output had bit 12 set - which means that SVM bit was enabled.
6. Ran 'wrmsr 0xc0000080 0xd01' which disabled the SVM bit.
7. kvm module loaded ok.
My questions are:
- was a BIOS update attempted? at least VMware uses the same check as
kvm, and probably virtualbox as well, so this problem should have been
seen before.
- was the vendor contacted? Not that I think we'll see a lot of good
from that.
- was this after a reset or cold boot?
- maybe a stealth rootkit is involved?
--
error compiling committee.c: too many arguments to function
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