Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757609AbcC2Q3C (ORCPT ); Tue, 29 Mar 2016 12:29:02 -0400 Received: from foss.arm.com ([217.140.101.70]:41505 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752873AbcC2Q3A (ORCPT ); Tue, 29 Mar 2016 12:29:00 -0400 Subject: Re: [PATCH v7 03/17] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn To: Shannon Zhao , linux-arm-kernel@lists.infradead.org, stefano.stabellini@citrix.com, david.vrabel@citrix.com References: <1458830676-27075-1-git-send-email-shannon.zhao@linaro.org> <1458830676-27075-4-git-send-email-shannon.zhao@linaro.org> Cc: devicetree@vger.kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will.deacon@arm.com, peter.huangpeng@huawei.com, xen-devel@lists.xen.org, zhaoshenglong@huawei.com From: Julien Grall Message-ID: <56FAAD48.2010401@arm.com> Date: Tue, 29 Mar 2016 17:28:56 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1458830676-27075-4-git-send-email-shannon.zhao@linaro.org> 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: 2036 Lines: 61 Hi Shannon, On 24/03/16 14:44, Shannon Zhao wrote: > Make xen_xlate_map_ballooned_pages work with 64K pages. In that case > Kernel pages are 64K in size but Xen pages remain 4K in size. Xen pfns > refer to 4K pages. > > Signed-off-by: Shannon Zhao > Reviewed-by: Stefano Stabellini > --- > drivers/xen/xlate_mmu.c | 26 ++++++++++++++++---------- > 1 file changed, 16 insertions(+), 10 deletions(-) > > diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c > index 9692656..28f728b 100644 > --- a/drivers/xen/xlate_mmu.c > +++ b/drivers/xen/xlate_mmu.c > @@ -207,9 +207,12 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, > void *vaddr; > int rc; > unsigned int i; > + unsigned long nr_pages; > + xen_pfn_t xen_pfn = 0; > > BUG_ON(nr_grant_frames == 0); > - pages = kcalloc(nr_grant_frames, sizeof(pages[0]), GFP_KERNEL); > + nr_pages = DIV_ROUND_UP(nr_grant_frames, XEN_PFN_PER_PAGE); > + pages = kcalloc(nr_pages, sizeof(pages[0]), GFP_KERNEL); > if (!pages) > return -ENOMEM; > > @@ -218,22 +221,25 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, > kfree(pages); > return -ENOMEM; > } > - rc = alloc_xenballooned_pages(nr_grant_frames, pages); > + rc = alloc_xenballooned_pages(nr_pages, pages); > if (rc) { > - pr_warn("%s Couldn't balloon alloc %ld pfns rc:%d\n", __func__, > - nr_grant_frames, rc); > + pr_warn("%s Couldn't balloon alloc %ld pages rc:%d\n", __func__, > + nr_pages, rc); > kfree(pages); > kfree(pfns); > return rc; > } > - for (i = 0; i < nr_grant_frames; i++) > - pfns[i] = page_to_pfn(pages[i]); > + for (i = 0; i < nr_grant_frames; i++) { > + if ((i % XEN_PFN_PER_PAGE) == 0) > + xen_pfn = page_to_xen_pfn(pages[i / XEN_PFN_PER_PAGE]); > + pfns[i] = pfn_to_gfn(xen_pfn++); > + } Would it be possible to re-use xen_for_each_gfn? This will avoid open-coding the loop to break down the Linux page. Regards, -- Julien Grall