Thanks very much for the reply.
I set all the four that you mentioned and am still having trouble with
intecepting guest IRET.
I print out the following right before the assembly instructions for
entering guest in vmx_vcpu_run() function in vmx.c file.
"vmcs config pin based 3f cpu based b6e0edfa cpu based2 fb interruptibility 8"
The printf statement producing this is :
printk(KERN_ERR " vmcs config pin based %x cpu based %x cpu based2 %x
interruptibility %x\n", vmcs_config.pin_based_exec_ctrl,
vmcs_config.cpu_based_exec_ctrl,
vmcs_config.cpu_based_2nd_exec_ctrl,vmcs_read32(GUEST_INTERRUPTIBILITY_INFO));
You can see that I am setting all four bits that you mentioned.
I am testing for vmexits due to IRET in the vmx_handle_exit()
function with the following test:
// this check is from Section 31.7.1.2 of the intel manual
"Resuming Guest Software after Handling an Exception"
if( ((vectoring_info & 2147483648) == 0) && ((vectoring_info &
255)!=8) && ((vectoring_info & 4096)==1) ){
printk(KERN_ERR "kvm nmi blocking exit complex check caught
using hw interception due to IRET \n");
}
if( exit_reason == EXIT_REASON_NMI_WINDOW ){
printk(KERN_ERR "kvm nmi window exit simple exit reason caught
using hw interception due to IRET \n");
}
Within the guest I run a BSD guest OS that returns from certain system
calls using the IRET instruction.
Do you have any thoughts on where I could be wrong?
Thanks !
On Fri, Feb 24, 2017 at 6:40 AM, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
>
>
> On 24/02/2017 11:32, sci sci wrote:
>> I tried several combinations of the following settings but with little
>> success.
>>
>> 1) Set/Unset Virtual NMIs which is bit 5 in pin based vm execution control
>> 2) Set/Unset bit 3 in guest interruptibility state (Blocking by NMI)
>> 3) Set/Unset "NMI-blocking" which is bit 3 in pin based NMI exiting
>> 4) Set/Unset "NMI-window exiting" which is bit 22 in primary processor
>> based VM execution control.
>
> Doing all four of these should do it:
>
> - set bit 3 in pin-based controls to cause a VMEXIT for host NMIs and
> enable special processing of IRET (paragraph 25.3)
>
> - set bit 5 in pin-based controls so that guest interruptibility state
> tracks virtual-NMI blocking
>
> - set bit 22 of VM executino control to enable the NMI-window vmexit
>
> - set bit 3 in guest interruptibility state to delay the NMI-window exit
> until the next IRET
>
> Paolo
