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Subject: Re: umip: AMD Ryzen 3900X, pagefault after emulate SLDT/SIDT
 instruction
To:     Andreas Rammhold <andi@notmuch.email>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        x86@kernel.org,
        Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Babu Moger <Babu.Moger@amd.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Jason Yan <yanaijie@huawei.com>,
        Brendan Shanks <bshanks@codeweavers.com>,
        linux-kernel@vger.kernel.org
References: <20200519143815.cpsd2xfx2kl3khsq@wrt>
From:   "H. Peter Anvin" <hpa@zytor.com>
Message-ID: <a0f55ad9-f85b-3b2a-e75d-43d4a54063fb@zytor.com>
Date:   Tue, 19 May 2020 17:17:28 -0700
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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