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Subject: Re: [PATCH 4/4] x86,module: Detect CRn and DRn manipulation
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     Steven Rostedt <rostedt@goodmis.org>, tglx@linutronix.de,
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        dcovelli@vmware.com, mhiramat@kernel.org,
        Wolfgang Mauerer <wolfgang.mauerer@oth-regensburg.de>
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From:   Jan Kiszka <jan.kiszka@siemens.com>
Message-ID: <aa7a2547-9670-d04f-4ca0-ab52abf30441@siemens.com>
Date:   Wed, 8 Apr 2020 10:59:02 +0200
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On 08.04.20 10:51, Peter Zijlstra wrote:
> On Wed, Apr 08, 2020 at 07:58:53AM +0200, Jan Kiszka wrote:
>> On 07.04.20 23:48, Steven Rostedt wrote:
> 
>>> Hmm, wont this break jailhouse?
> 
> Breaking it isn't a problem, it's out of tree and it should be fixable.
> 
>> Yes, possibly. We load the hypervisor binary via request_firmware into
>> executable memory and then jump into it. So most of the "suspicious" code is
> 
> W.T.H. does the firmware loader have the ability to give executable
> memory? We need to kill that too. /me goes find.
> 

At the risk of cutting our own branch off: That's not the firmware 
loader, it's ioremap with PAGE_KERNEL_EXEC.

Jan

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