From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54166) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WPwo7-0003lc-1p for qemu-devel@nongnu.org; Tue, 18 Mar 2014 12:24:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WPwo0-0001jy-RC for qemu-devel@nongnu.org; Tue, 18 Mar 2014 12:24:02 -0400 Received: from mx1.redhat.com ([209.132.183.28]:26804) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WPwo0-0001ju-Ja for qemu-devel@nongnu.org; Tue, 18 Mar 2014 12:23:56 -0400 Date: Tue, 18 Mar 2014 12:23:52 -0400 From: Luiz Capitulino Message-ID: <20140318122352.0e58240f@redhat.com> In-Reply-To: <532859FD.4090907@siemens.com> References: <20140317215455.2f14b61f@redhat.com> <5327F398.7040509@siemens.com> <5327F771.7040205@redhat.com> <53282052.1020909@siemens.com> <20140318090043.3eba6b1a@redhat.com> <532859FD.4090907@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH for-2.0?] target-i386: fix gdb debugging with large memory guests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: Paolo Bonzini , qemu-devel , afaerber@suse.de, peter.maydell@linaro.org On Tue, 18 Mar 2014 15:36:45 +0100 Jan Kiszka wrote: > >> Right, this belongs in the "if (env->hflags & HF_LMA_MASK)" block. > >> > >> And the subject or description should mention that > >> x86_cpu_get_phys_page_debug was lacking support for 1G hugepages. > > > > To be honest, although the PS bit is set and that indicates a 1GB page, > > I didn't know Linux does that. I thought Linux would use 4KB pages for > > everything unless it's explicitly asked to use bigger pages. Also, note that > > I was using gdb to debug really early kernel boot code (start_kernel()). > > I could imagine that Linux initially creates a giant identity mapping > page table for the startup process and only later on switches to > fine-grained tables of 4K and 2M pages. Giant pages still require > hughtlbfs, IIRC. > > > > > I'd feel more confident to have such a changelog after I find out where > > exactly Linux sets that bit, but I won't have time in the next days. On the > > other hand, the patch does fix the problem to me. > > Don't worry about Linux (the code should work with any OS anyway), just > believe your reviewers. ;) Alternatively, check Intel IA32 SDM on page > table structures. OK, so you want me to change the subject? Anything else for v2?