From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751204AbdAPPDX (ORCPT ); Mon, 16 Jan 2017 10:03:23 -0500 Received: from foss.arm.com ([217.140.101.70]:56188 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750840AbdAPPDW (ORCPT ); Mon, 16 Jan 2017 10:03:22 -0500 Subject: Re: [PATCH V2] Xen: ARM: Zero reserved fields of xatp before making hypervisor call To: Stefano Stabellini , Juergen Gross References: <1482886052-30111-1-git-send-email-anjiandi@codeaurora.org> Cc: Jiandi An , boris.ostrovsky@oracle.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org From: Julien Grall Message-ID: <94f7da28-6d5c-b86b-9e96-353e804c9828@arm.com> Date: Mon, 16 Jan 2017 15:03:19 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Stefano, On 03/01/17 18:03, Stefano Stabellini wrote: > 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 >>> --- >>> 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. I think this patch should be backported to stable trees because the issue could appear depending on the compiler. Cheers, -- Julien Grall