linux-kernel - Re: umip: AMD Ryzen 3900X, pagefault after emulate SLDT/SIDT instruction

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Date:   Tue, 19 May 2020 17:17:28 -0700
From:   "H. Peter Anvin" <hpa@...or.com>
To:     Andreas Rammhold <andi@...much.email>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org,
        Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Babu Moger <Babu.Moger@....com>,
        Kefeng Wang <wangkefeng.wang@...wei.com>,
        Jason Yan <yanaijie@...wei.com>,
        Brendan Shanks <bshanks@...eweavers.com>,
        linux-kernel@...r.kernel.org
Subject: Re: umip: AMD Ryzen 3900X, pagefault after emulate SLDT/SIDT
 instruction

On 2020-05-19 07:38, Andreas Rammhold wrote:
> Hi,
> 
> I've been running into a weird problem with UMIP on a current Ryzen
> 3900x with kernel 5.6.11 where a process receives a page fault after the
> kernel handled the SLDT (or SIDT) instruction (emulation).
> 
> The program I am running is run through WINE in 32bit mode and tries to
> figure out if it is running in a VMWare machine by comparing the results
> of SLDT against well known constants (basically as shown in the
> [example] linked below).
> 

Extremely weird. What is it expecting to happen -- or rather, what do you
*want* it to do?

	-hpa