From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1LZM6J-0006hv-99 for qemu-devel@nongnu.org; Tue, 17 Feb 2009 04:18:47 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1LZM6H-0006he-I3 for qemu-devel@nongnu.org; Tue, 17 Feb 2009 04:18:46 -0500 Received: from [199.232.76.173] (port=48002 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1LZM6H-0006hV-EF for qemu-devel@nongnu.org; Tue, 17 Feb 2009 04:18:45 -0500 Received: from lizzard.sbs.de ([194.138.37.39]:20412) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1LZM6G-0008Kd-Su for qemu-devel@nongnu.org; Tue, 17 Feb 2009 04:18:45 -0500 Received: from mail1.sbs.de (localhost [127.0.0.1]) by lizzard.sbs.de (8.12.11.20060308/8.12.11) with ESMTP id n1H9Id7R022787 for ; Tue, 17 Feb 2009 10:18:41 +0100 Received: from [139.25.109.167] (mchn012c.mchp.siemens.de [139.25.109.167] (may be forged)) by mail1.sbs.de (8.12.11.20060308/8.12.11) with ESMTP id n1H9IdSQ021134 for ; Tue, 17 Feb 2009 10:18:39 +0100 Message-ID: <499A80EF.30903@siemens.com> Date: Tue, 17 Feb 2009 10:18:39 +0100 From: Jan Kiszka MIME-Version: 1.0 References: <309a0db40902170027s75a1505fn6de64be94a82e05e@mail.gmail.com> In-Reply-To: <309a0db40902170027s75a1505fn6de64be94a82e05e@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: Resume Flag support on i386/x86_64? Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Alex Smith wrote: > Hi, > > Recently support for hardware breakpoint support on i386/x86_64 was > added (revision 5747 - > http://lists.gnu.org/archive/html/qemu-devel/2008-11/msg01025.html). > I've been using hardware breakpoints while writing a debugger for my > hobby OS kernel, however I've discovered that despite support being > added for them in QEMU, the Resume Flag (bit 16 in EFLAGS) is not > supported. When this flag is set on return from an interrupt, the CPU > should ignore instruction breakpoints for the next instruction, and > then clear the flag after checking for breakpoints (there's a > description on page 18-10 of the Intel Software Developer's Manual > Volume 3B). Mmh, guess I missed this... > > Would it be possible to implement support for this? I think so. Will take some fiddling within the code generator, will see what I can do, but you have to be patient (long to-do list...) -- or look into this on your own. ;) Well, in the meantime you may also find a correct behavior by running qemu in kvm mode because then the real hardware is used, and that should already work as expected. Jan -- Siemens AG, Corporate Technology, CT SE 2 Corporate Competence Center Embedded Linux