Subject: Re: [RFC 08/17] x86/asm/64: De-Xen-ify our NMI code
To: Andy Lutomirski <luto@kernel.org>
Cc: X86 ML <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Boris Ostrovsky <boris.ostrovsky@oracle.com>,
        Kees Cook <keescook@chromium.org>
References: <cover.1504733277.git.luto@kernel.org>
 <f0d45728756ebe8540edcc7b0da57bb77b3b719e.1504733277.git.luto@kernel.org>
 <decdea78-f65a-ddc1-4b0c-e18964790def@suse.com>
 <CALCETrXRFDbzed7yrBH8Hdmy3iZnAav+qujCjVmJ5FgF_adhXw@mail.gmail.com>
From: Juergen Gross <jgross@suse.com>
Message-ID: <c26a4829-9e4f-8150-3e39-bf0c47ac58c6@suse.com>
Date: Fri, 8 Sep 2017 06:26:46 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.3.0
MIME-Version: 1.0
In-Reply-To: <CALCETrXRFDbzed7yrBH8Hdmy3iZnAav+qujCjVmJ5FgF_adhXw@mail.gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: de-DE
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 656
Lines: 21

On 07/09/17 20:38, Andy Lutomirski wrote:
> On Thu, Sep 7, 2017 at 2:34 AM, Juergen Gross <jgross@suse.com> wrote:
>> On 06/09/17 23:36, Andy Lutomirski wrote:
>>> Xen PV is fundamentally incompatible with our fancy NMI code: it
>>> doesn't use IST at all, and Xen entries clobber two stack slots
>>> below the hardware frame.
>>>
>>> Drop Xen PV support from our NMI code entirely.
>>>
>>> XXX: Juergen: could you write and test the tiny patch needed to
>>> make Xen PV have a xen_nmi entry that handles NMIs?  I don't know
>>> how to test it.
>>
>> You mean something like the attached one?
> 
> Yes.  Mind if I add it to my series?

Go ahead!


Juergen