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Date:   Wed, 18 Sep 2019 22:56:16 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Larry Finger <Larry.Finger@lwfinger.net>
Cc:     Linus Torvalds <torvalds@linux-foundation.org>,
        Christoph Hellwig <hch@lst.de>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH] x86/mm: Remove set_pages_x() and set_pages_nx()
Message-ID: <20190918205616.GA23251@lst.de>
References: <20190918164121.30006-1-Larry.Finger@lwfinger.net> <20190918164518.GA19222@lst.de> <b4fa6ab6-ab30-fc05-0f9f-93c41e7e8c79@lwfinger.net> <CAHk-=wji2fMDpSwvR4U8FkKBx8=eZtg3CmWtH7hACzeHbBei8A@mail.gmail.com> <bd5684ee-afaf-a9ba-6c32-15d2aa94733c@lwfinger.net>
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On Wed, Sep 18, 2019 at 01:17:13PM -0500, Larry Finger wrote:
> The external module is vboxdrv, which is part of VirtualBox. The setting of 
> pages to be executable appears to have been added in kernel 2.4.20.
>
> I am now testing with the former calls to set_pages_x() and set_pages_nx() 
> disabled. Thus far, VMs seem to be running OK. I will contact Oracle to 
> discuss the matter with them and see if there is some special case that 
> requires this facility. If there is one, then they will need to discuss it 
> with you and Christoph.

Well, in this case the API is called /dev/kvm.  There is really
absolutely no reason for anyone badly reinventing the low-level
VT and SVM code when they can just use the kernel kvm support, which
already has at least half a dozen users.