linux-kernel - Re: [PATCH] x86/xen: allow userspace access during hypercalls

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Message-ID: <20170626124505.GV1268@mail-itl>
Date:   Mon, 26 Jun 2017 14:45:05 +0200
From:   Marek Marczykowski-Górecki 
        <marmarek@...isiblethingslab.com>
To:     Juergen Groß <jgross@...e.com>
Cc:     xen-devel@...ts.xenproject.org,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Andrew Cooper <andrew.cooper3@...rix.com>, x86@...nel.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] x86/xen: allow userspace access during hypercalls

On Mon, Jun 26, 2017 at 02:05:48PM +0200, Juergen Groß wrote:
> On 06/23/2017 02:47 PM, Marek Marczykowski-Górecki wrote:
> > Userspace application can do a hypercall through /dev/xen/privcmd, and
> > some for some hypercalls argument is a pointers to user-provided
> > structure. When SMAP is supported and enabled, hypervisor can't access.
> > So, lets allow it.
> 
> What about HYPERVISOR_dm_op?

Indeed, arguments copied to kernel space there are only addresses of
buffers. Will send v2 in a moment.
But I can't test it right now, as for my understanding this require
HVM/PVHv2 dom0 or stubdomain...

-- 
Best Regards,
Marek Marczykowski-Górecki
Invisible Things Lab
A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?

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