Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751184AbdFAMu7 (ORCPT ); Thu, 1 Jun 2017 08:50:59 -0400 Received: from foss.arm.com ([217.140.101.70]:55714 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751078AbdFAMu5 (ORCPT ); Thu, 1 Jun 2017 08:50:57 -0400 Subject: Re: [PATCH] xen/privcmd: Support correctly 64KB page granularity when mapping memory To: Boris Ostrovsky , xen-devel@lists.xen.org References: <20170531130357.14492-1-julien.grall@arm.com> <7199e366-f56a-acc8-ffa5-0c85d6975049@oracle.com> Cc: sstabellini@kernel.org, jgross@suse.com, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Feng Kan From: Julien Grall Message-ID: <592886a8-1443-6475-e318-85cb9acecead@arm.com> Date: Thu, 1 Jun 2017 13:50:44 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <7199e366-f56a-acc8-ffa5-0c85d6975049@oracle.com> 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 Content-Length: 1687 Lines: 52 Hi Boris, On 31/05/17 14:54, Boris Ostrovsky wrote: > On 05/31/2017 09:03 AM, Julien Grall wrote: >> Commit 5995a68 "xen/privcmd: Add support for Linux 64KB page granularity" did >> not go far enough to support 64KB in mmap_batch_fn. >> >> The variable 'nr' is the number of 4KB chunk to map. However, when Linux >> is using 64KB page granularity the array of pages (vma->vm_private_data) >> contain one page per 64KB. Fix it by incrementing st->index correctly. >> >> Furthermore, st->va is not correctly incremented as PAGE_SIZE != >> XEN_PAGE_SIZE. >> >> Fixes: 5995a68 ("xen/privcmd: Add support for Linux 64KB page granularity") >> CC: stable@vger.kernel.org >> Reported-by: Feng Kan >> Signed-off-by: Julien Grall >> --- >> drivers/xen/privcmd.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/xen/privcmd.c b/drivers/xen/privcmd.c >> index 7a92a5e1d40c..feca75b07fdd 100644 >> --- a/drivers/xen/privcmd.c >> +++ b/drivers/xen/privcmd.c >> @@ -362,8 +362,8 @@ static int mmap_batch_fn(void *data, int nr, void *state) >> st->global_error = 1; >> } >> } >> - st->va += PAGE_SIZE * nr; >> - st->index += nr; >> + st->va += XEN_PAGE_SIZE * nr; >> + st->index += nr / XEN_PFN_PER_PAGE; >> >> return 0; >> } > > > Are we still using PAGE_MASK for xen_remap_domain_gfn_array()? Do you mean in the xen_xlate_remap_gfn_array implementation? If so there are no use of PAGE_MASK as the code has been converted to support 64K page granularity. If you mean the x86 version of xen_remap_domain_gfn_array, then we don't really care as x86 only use 4KB page granularity. Cheers, -- Julien Grall