From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751139AbcARFJP (ORCPT ); Mon, 18 Jan 2016 00:09:15 -0500 Received: from szxga03-in.huawei.com ([119.145.14.66]:2310 "EHLO szxga03-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750945AbcARFJN (ORCPT ); Mon, 18 Jan 2016 00:09:13 -0500 Message-ID: <569C7363.80106@huawei.com> Date: Mon, 18 Jan 2016 13:08:51 +0800 From: Shannon Zhao User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Stefano Stabellini CC: , , , , , , , , , , , , , Subject: Re: [Xen-devel] [PATCH v2 03/16] Xen: xlate: Use page_to_xen_pfn instead of page_to_pfn References: <1452840929-19612-1-git-send-email-zhaoshenglong@huawei.com> <1452840929-19612-4-git-send-email-zhaoshenglong@huawei.com> In-Reply-To: Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.16.142] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020205.569C7372.0089,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-05-26 15:14:31, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: a5a2cc0b0cbd41022bdccb1c0f636528 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2016/1/16 1:08, Stefano Stabellini wrote: > On Fri, 15 Jan 2016, Shannon Zhao wrote: >> From: Shannon Zhao >> >> Use page_to_xen_pfn in case of 64KB page. >> >> Signed-off-by: Shannon Zhao >> --- >> drivers/xen/xlate_mmu.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c >> index 9692656..b9fcc2c 100644 >> --- a/drivers/xen/xlate_mmu.c >> +++ b/drivers/xen/xlate_mmu.c >> @@ -227,7 +227,7 @@ int __init xen_xlate_map_ballooned_pages(xen_pfn_t **gfns, void **virt, >> return rc; >> } >> for (i = 0; i < nr_grant_frames; i++) >> - pfns[i] = page_to_pfn(pages[i]); >> + pfns[i] = page_to_xen_pfn(pages[i]); > > Shannon, thanks for the patch. > > Keeping in mind that in the 64K case, kernel pages are 64K but xen pages > are still 4K, I think you also need to allocate > (nr_grant_frames/XEN_PFN_PER_PAGE) kernel pages (assuming that they are > allocated contiguously): nr_grant_frames refers to 4K pages, while > xen_xlate_map_ballooned_pages is allocating pages on a 64K granularity > (sizeof(pages[0]) == 64K). > > Be careful that alloc_xenballooned_pages deals with 64K pages (because > it deals with kernel pages), while xen_pfn_t is always 4K based (because > it deals with Xen pfns). > > Please test it with and without CONFIG_ARM64_64K_PAGES. Thanks! > Stefano, thanks for your explanation. How about below patch? diff --git a/drivers/xen/xlate_mmu.c b/drivers/xen/xlate_mmu.c index 9692656..e1f7c95 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] = xen_pfn++; + } - vaddr = vmap(pages, nr_grant_frames, 0, PAGE_KERNEL); + vaddr = vmap(pages, nr_pages, 0, PAGE_KERNEL); if (!vaddr) { - pr_warn("%s Couldn't map %ld pfns rc:%d\n", __func__, - nr_grant_frames, rc); - free_xenballooned_pages(nr_grant_frames, pages); + pr_warn("%s Couldn't map %ld pages rc:%d\n", __func__, + nr_pages, rc); + free_xenballooned_pages(nr_pages, pages); kfree(pages); kfree(pfns); return -ENOMEM; -- Shannon