On 01/19/2010 01:09 AM, Matteo Signorini wrote:
Hi guys,
I would like to intercept the vm-exit whenever the guest executes a
lidt/sidt instruction.
I know that lidt/sidt instructions cause a vm-exit if and only if
these condition are satisfied:
-commands are executed in vmx non-root environment
-the "descriptor-table exiting" field of the secondary vm-execution
control structure is enabled
The first condition is satisfied because the guest OS executes the
lidt/sidt in the boot routine so we are in the vmx non-root
environment.
To satisfy the second condition, I set up the 31th bit in the primary
vm-execution control to 1 to enable the secondary vm-execution
control,
then I set up the 2nd bit of the secondary vm-execution control to 1
to enable the "descriptor-table exiting".
The problem is that I never get the exit_code=46 (that should
correspond to the IDTR access as shown in the Intel developer's
manual).
What I get is exit_code=0 and then the VM freezes.
I wonder why I get 0 as exit reason instead of 46?
Qemu gives me the following error message:
"kvm: unhandled exit 7
kvm_run returned -22"
The unhandled exit code correspond to the 7th vm-instruction error
number referred to: "VM-Entry with invalid control field(s)"
Did you check whether your processor supports descriptor-table exiting?
The 'vmxcap' script can help determine that.
--
error compiling committee.c: too many arguments to function
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