Re: [PATCH] x86: kvm: reset the bootstrap processor when it gets an INIT

Jan Kiszka
2013-03-11T19:01:30Z

On 2013-03-11 19:51, Gleb Natapov wrote:
>>> On Intel:
>>> CPU 1 CPU 2 in a guest mode
>>> send INIT
>>> send SIPI
>>> INIT vmexit
>>> vmxoff
>>> reset and start from SIPI vector
>>
>> Is SIPI sticky as well, even if the CPU is not in the wait-for-SIPI
>> state (but runnable and in vmxon) while receiving it?
>>
> That what they seams to be saying:
> However, an INIT and SIPI interrupts sent to a CPU during time when
> it is in a VMX mode are remembered and delivered, perhaps hours later,
> when the CPU exits the VMX mode
>
> Otherwise their exploit will not work.

Very weird, specifically as SIPI is not just a binary event but carries
payload. Will another SIPI event overwrite the previously "saved"
vector? We are deep into an underspecified area...

Jan

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