From mboxrd@z Thu Jan  1 00:00:00 1970
From: Razvan Cojocaru <rcojocaru@bitdefender.com>
Subject: Re: Getting the XSAVE size from userspace
Date: Thu, 5 Nov 2015 12:47:08 +0200
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To: Jan Beulich <JBeulich@suse.com>
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On 11/05/2015 12:42 PM, Jan Beulich wrote:
>>>> On 05.11.15 at 10:52, <rcojocaru@bitdefender.com> wrote:
>> I need to get the XSAVE size from userspace. The easiest way seems to be
>> to use the XEN_DOMCTL_getvcpuextstate hypercall, but that hypercall is
>> not public / there's no xenctrl.h wrapper for it.
> 
> Before going into any detail of the rest of your mail - any reason you
> can't just consult CPUID output?

That's because the userspace application doesn't live in dom0, but in a
dedicated privileged domain, and I'm unsure if a CPUID issued there
yields the same results as a CPUID issued in dom0. So I thought the
safest way is to get the information directly from the hypervisor. Is
this assumption incorrect?


Thanks,
Razvan