From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH] libxc/arm: align to page size the base address of the device tree Date: Wed, 20 Nov 2013 13:17:58 +0000 Message-ID: <528CB686.3000907@linaro.org> References: <1384887144-7229-1-git-send-email-julien.grall@linaro.org> <1384940907.28441.11.camel@kazak.uk.xensource.com> <528CB359.4060200@linaro.org> <1384953217.6071.25.camel@kazak.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Vj7fO-0006t2-CJ for xen-devel@lists.xenproject.org; Wed, 20 Nov 2013 13:18:02 +0000 Received: by mail-we0-f173.google.com with SMTP id t61so2460101wes.4 for ; Wed, 20 Nov 2013 05:18:00 -0800 (PST) In-Reply-To: <1384953217.6071.25.camel@kazak.uk.xensource.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ian Campbell Cc: xen-devel@lists.xenproject.org, tim@xen.org, ian.jackson@eu.citrix.com, stefano.stabellini@citrix.com, patches@linaro.org List-Id: xen-devel@lists.xenproject.org On 11/20/2013 01:13 PM, Ian Campbell wrote: > On Wed, 2013-11-20 at 13:04 +0000, Julien Grall wrote: >> >> On 11/20/2013 09:48 AM, Ian Campbell wrote: >>> On Tue, 2013-11-19 at 18:52 +0000, Julien Grall wrote: >>>> xc_dom_alloc_segment requires start address to be page align. >>> >>> I wonder why I didn't see this? It seems very unlikely that my dtb would >>> be exactly page sized, yet it works... Ah, I have >128M of RAM in my >>> guest so the base would be 128M. Well spotted. >>> >>> I think it would be slightly preferable to round dtbsize up to a page. >>> e.g. the following. What do you think? >>> >> >> Sounds good to me. I wrote my patch in the other way because I though >> RAM size can be non-page aligned. > > That would be concern except the sizes are defined immediately above as > shifts based on page numbers. > >> >>> 8>------------------ >>> >>> From 079a2815d86567de1cbb541541d08a0b9ac3d18d Mon Sep 17 00:00:00 2001 >>> From: Ian Campbell >>> Date: Wed, 20 Nov 2013 09:45:32 +0000 >>> Subject: [PATCH] libxl: arm: ensure DTB is page aligned >>> >>> xc_dom_alloc_segment requires this. Since rambase and ramend are both page >>> aligned, rounding up the DTB is sufficient. >>> >>> Reported-by: Julien Grall >>> Signed-off-by: Ian Campbell >>> --- >>> tools/libxc/xc_dom_arm.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/tools/libxc/xc_dom_arm.c b/tools/libxc/xc_dom_arm.c >>> index ffe575b..a40e04d 100644 >>> --- a/tools/libxc/xc_dom_arm.c >>> +++ b/tools/libxc/xc_dom_arm.c >>> @@ -282,7 +282,7 @@ int arch_setup_meminit(struct xc_dom_image *dom) >>> { >>> const uint64_t rambase = dom->rambase_pfn << XC_PAGE_SHIFT; >>> const uint64_t ramend = rambase + ( dom->total_pages << XC_PAGE_SHIFT ); >>> - const uint64_t dtbsize = ( dom->devicetree_size + 3 ) & ~0x3; >>> + const uint64_t dtbsize = ROUNDUP(dom->devicetree_size, XC_PAGE_SHIFT); >> >> XC_PAGE_SHIFT only contains the shift. You should use XC_PAGE_SIZE. > > That's not how ROUNDUP is defined in libxc: > #define ROUNDUP(_x,_w) (((unsigned long)(_x)+(1UL<<(_w))-1) & ~((1UL<<(_w))-1)) > > so it expects _w (width?) to be the shift. Oh right, I though it was defined as in xen. In any case, I think you should use XC_DOM_PAGE_SHIFT(dom). -- Julien Grall