Re: [PATCH] KVM: nSVM/nVMX: Implement vmexit on INIT assertion

[Nadav Har'El <nyh@math.technion.ac.il>]

On Sun, Feb 24, 2013, Jan Kiszka wrote about "[PATCH] KVM: nSVM/nVMX: Implement vmexit on INIT assertion":
> From: Jan Kiszka <jan.kiszka@siemens.com>
> 
> On Intel, raising INIT causing an unconditional vmexit. On AMD, this is
> controlled by the interception mask.

Hi,

I never tried to closely follow the KVM code paths related this code,
but I do have one question: The VMX spec says:

   "The INIT signal is blocked whenever a logical processor is in VMX root
    operation. It is not blocked in VMX non-root operation. Instead, INITs
    cause VM exits (see Section 22.3, Other Causes of VM Exits)."

So when running a non-nested L1 guest, or an L2 guest, the new behavior
appears correct. However, it looks like if L1 is running in root
mode (i.e., did VMXON once but not running L2 now), the INIT signal
needs to be blocked, not do what it does now. It appears (but I'm not sure...)
that right now, it causes the L1 guest to lock up, and is not ignored? 

Nadav.

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Nadav Har'El                        |        Monday, Feb 25 2013, 15 Adar 5773
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