From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from list by lists.gnu.org with archive (Exim 4.71) id 1aXmnp-0001yT-Br for mharc-grub-devel@gnu.org; Mon, 22 Feb 2016 04:29:13 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53121) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aXmnn-0001w7-7D for grub-devel@gnu.org; Mon, 22 Feb 2016 04:29:12 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aXmni-0000XW-9F for grub-devel@gnu.org; Mon, 22 Feb 2016 04:29:11 -0500 Received: from mx2.suse.de ([195.135.220.15]:40630) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aXmnh-0000XM-VG for grub-devel@gnu.org; Mon, 22 Feb 2016 04:29:06 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id BF31EAC0E; Mon, 22 Feb 2016 09:29:04 +0000 (UTC) Subject: Re: [PATCH v4 10/11] xen: modify page table construction To: Daniel Kiper References: <1456120999-5639-1-git-send-email-jgross@suse.com> <1456120999-5639-11-git-send-email-jgross@suse.com> <20160222091748.GO3482@olila.local.net-space.pl> From: Juergen Gross X-Enigmail-Draft-Status: N1110 Message-ID: <56CAD4E0.80304@suse.com> Date: Mon, 22 Feb 2016 10:29:04 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 MIME-Version: 1.0 In-Reply-To: <20160222091748.GO3482@olila.local.net-space.pl> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x (no timestamps) [generic] X-Received-From: 195.135.220.15 Cc: grub-devel@gnu.org, phcoder@gmail.com, mchang@suse.com, xen-devel@lists.xen.org X-BeenThere: grub-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list Reply-To: The development of GNU GRUB List-Id: The development of GNU GRUB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Feb 2016 09:29:12 -0000 On 22/02/16 10:17, Daniel Kiper wrote: > On Mon, Feb 22, 2016 at 07:03:18AM +0100, Juergen Gross wrote: >> Modify the page table construction to allow multiple virtual regions >> to be mapped. This is done as preparation for removing the p2m list >> from the initial kernel mapping in order to support huge pv domains. >> >> This allows a cleaner approach for mapping the relocator page by >> using this capability. >> >> The interface to the assembler level of the relocator has to be changed >> in order to be able to process multiple page table areas. >> >> Signed-off-by: Juergen Gross >> --- >> V4: align variables in assembly sources >> use separate structure define as requested by Daniel Kiper >> >> V3: use constants instead of numbers as requested by Daniel Kiper >> add lots of comments to assembly code as requested by Daniel Kiper >> --- >> grub-core/lib/i386/xen/relocator.S | 88 ++++++---- >> grub-core/lib/x86_64/xen/relocator.S | 135 ++++++--------- >> grub-core/lib/xen/relocator.c | 28 ++- >> grub-core/loader/i386/xen.c | 325 ++++++++++++++++++++++++----------- >> include/grub/i386/memory.h | 7 + >> include/grub/xen/relocator.h | 6 +- >> 6 files changed, 359 insertions(+), 230 deletions(-) >> >> diff --git a/grub-core/lib/i386/xen/relocator.S b/grub-core/lib/i386/xen/relocator.S >> index 694a54c..f8d135a 100644 >> --- a/grub-core/lib/i386/xen/relocator.S >> +++ b/grub-core/lib/i386/xen/relocator.S >> @@ -102,6 +112,10 @@ VARIABLE(grub_relocator_xen_remap_continue) >> >> jmp *%eax >> >> + .p2align 2 > > I do not think this is needed but... Even if the processor does allow unaligned loads: it's cleaner to avoid them. > >> diff --git a/grub-core/lib/x86_64/xen/relocator.S b/grub-core/lib/x86_64/xen/relocator.S >> index 92e9e72..38ae157 100644 >> --- a/grub-core/lib/x86_64/xen/relocator.S >> +++ b/grub-core/lib/x86_64/xen/relocator.S >> >> jmp *%rax >> >> -LOCAL(mmu_op): >> + .p2align 3 > > Ditto... > >> diff --git a/grub-core/lib/xen/relocator.c b/grub-core/lib/xen/relocator.c >> index 8f427d3..a05b253 100644 >> --- a/grub-core/lib/xen/relocator.c >> +++ b/grub-core/lib/xen/relocator.c >> @@ -29,6 +29,11 @@ >> >> typedef grub_addr_t grub_xen_reg_t; >> >> +struct grub_relocator_xen_paging_area { >> + grub_xen_reg_t start; >> + grub_xen_reg_t size; >> +}; >> + > > ... this should have GRUB_PACKED because compiler may > add padding to align size member. Why would the compiler add padding to a structure containing two items of the same type? I don't think the C standard would allow this. grub_xen_reg_t is either unsigned (32 bit) or unsigned long (64 bit). There is no way this could require any padding. Juergen