Re: [PATCH V2] Xen: ARM: Zero reserved fields of xatp before making hypervisor call

Path	csiph.com!1.us.feeder.erje.net!feeder.erje.net!2.eu.feeder.erje.net!newsfeed.fsmpi.rwth-aachen.de!newsfeed.straub-nv.de!news.unit0.net!news.panservice.it!bofh.it!news.nic.it!robomod
From	Stefano Stabellini <sstabellini@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH V2] Xen: ARM: Zero reserved fields of xatp before making hypervisor call
Date	Tue, 03 Jan 2017 19:10:01 +0100
Message-ID	<sVBH3-1F1-17@gated-at.bofh.it> (permalink)
References	<sTaBj-RM-3@gated-at.bofh.it> <sV48p-2C9-3@gated-at.bofh.it>
X-X-Sender	sstabellini@sstabellini-ThinkPad-X260
User-Agent	Alpine 2.10 (DEB 1266 2009-07-14)
MIME-Version	1.0
Content-Type	TEXT/PLAIN; charset=US-ASCII
Sender	robomod@news.nic.it
List-ID	<linux-kernel.vger.kernel.org>
X-Mailing-List	linux-kernel@vger.kernel.org
Approved	robomod@news.nic.it
Lines	42
Organization	linux.* mail to news gateway
X-Original-Cc	Jiandi An <anjiandi@codeaurora.org>, boris.ostrovsky@oracle.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org, sstabellini@kernel.org, julien.grall@arm.com
X-Original-Date	Tue, 3 Jan 2017 10:03:59 -0800 (PST)
X-Original-Message-ID	<alpine.DEB.2.10.1701031003050.17742@sstabellini-ThinkPad-X260>
X-Original-References	<1482886052-30111-1-git-send-email-anjiandi@codeaurora.org> <a926f4b6-0bfd-bcd6-3313-e1bd01ce4fa2@suse.com>
X-Original-Sender	linux-kernel-owner@vger.kernel.org
Xref	csiph.com linux.kernel:1550028

Show key headers only | View raw

On Mon, 2 Jan 2017, Juergen Gross wrote:
> On 28/12/16 01:47, Jiandi An wrote:
> > Ensure all reserved fields of xatp are zero before making
> > hypervisor call to XEN in xen_map_device_mmio().
> > xenmem_add_to_physmap_one() in XEN fails the mapping request if
> > extra.res reserved field in xatp is not zero for XENMAPSPACE_dev_mmio
> > request.
> > 
> > Signed-off-by: Jiandi An <anjiandi@codeaurora.org>
> > ---
> > Changed zeroing xatp to a static initialization
> > of .domid and .space for xatp.
> > 
> >  drivers/xen/arm-device.c | 8 +++++---
> >  1 file changed, 5 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/xen/arm-device.c b/drivers/xen/arm-device.c
> > index 778acf8..85dd20e 100644
> > --- a/drivers/xen/arm-device.c
> > +++ b/drivers/xen/arm-device.c
> > @@ -58,9 +58,13 @@ static int xen_map_device_mmio(const struct resource *resources,
> >  	xen_pfn_t *gpfns;
> >  	xen_ulong_t *idxs;
> >  	int *errs;
> > -	struct xen_add_to_physmap_range xatp;
> >  
> >  	for (i = 0; i < count; i++) {
> > +		struct xen_add_to_physmap_range xatp = {
> > +			.domid = DOMID_SELF,
> > +			.space = XENMAPSPACE_dev_mmio
> > +		};
> > +
> 
> I still don't see the need to re-initialize the input parts of xatp
> on each loop iteration unless you can show the need for it (e.g. a
> buggy hypervisor version not conforming to the interface specification).
> 
> OTOH I don't feel really strong about it and let Stefano being the
> maintainer for the ARM parts decide.

I don't feel strongly about this either - I think this patch is good
enough. I'll apply to xentip.

Thread

[PATCH V2] Xen: ARM: Zero reserved fields of xatp before making hypervisor call Jiandi An <anjiandi@codeaurora.org> - 2016-12-28 01:50 +0100
  Re: [PATCH V2] Xen: ARM: Zero reserved fields of xatp before making  hypervisor call Juergen Gross <jgross@suse.com> - 2017-01-02 07:20 +0100
    Re: [PATCH V2] Xen: ARM: Zero reserved fields of xatp before making  hypervisor call Stefano Stabellini <sstabellini@kernel.org> - 2017-01-03 19:10 +0100
      Re: [PATCH V2] Xen: ARM: Zero reserved fields of xatp before making  hypervisor call Julien Grall <julien.grall@arm.com> - 2017-01-16 16:10 +0100

csiph-web