From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45503) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XhDBk-000476-Ip for qemu-devel@nongnu.org; Thu, 23 Oct 2014 03:52:10 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XhDBe-0007w5-GK for qemu-devel@nongnu.org; Thu, 23 Oct 2014 03:52:04 -0400 Received: from mail.ispras.ru ([83.149.199.45]:58563) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XhDBe-0007vu-8o for qemu-devel@nongnu.org; Thu, 23 Oct 2014 03:51:58 -0400 From: "Pavel Dovgaluk" References: <20141022113831.9548.36452.stgit@PASHA-ISP> <5447A8BB.1060707@greensocs.com> <000901cfee86$3c9f1280$b5dd3780$@Dovgaluk@ispras.ru> <5448B0B3.9040702@greensocs.com> In-Reply-To: <5448B0B3.9040702@greensocs.com> Date: Thu, 23 Oct 2014 11:52:00 +0400 Message-ID: <000e01cfee96$3a1ce130$ae56a390$@Dovgaluk@ispras.ru> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Content-Language: ru Subject: Re: [Qemu-devel] [PATCH] i386: fix breakpoints handling in icount mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: 'Frederic Konrad' , qemu-devel@nongnu.org Cc: pbonzini@redhat.com, zealot351@gmail.com, maria.klimushenkova@ispras.ru, mark.burton@greensocs.com, batuzovk@ispras.ru > From: Frederic Konrad [mailto:fred.konrad@greensocs.com] > On 23/10/2014 07:57, Pavel Dovgaluk wrote: > >> From: Frederic Konrad [mailto:fred.konrad@greensocs.com] > >> On 22/10/2014 13:38, Pavel Dovgalyuk wrote: > >> > >> Hi Pavel, > >>> This patch fixes instructions counting when execution is stopped on > >>> breakpoint (e.g. set from gdb). Without a patch extra instruction is translated > >>> and icount is incremented by invalid value (which equals to number of > >>> executed instructions + 1). > >>> > >>> Signed-off-by: Pavel Dovgalyuk > >>> --- > >>> target-i386/translate.c | 3 ++- > >>> 1 files changed, 2 insertions(+), 1 deletions(-) > >>> > >>> diff --git a/target-i386/translate.c b/target-i386/translate.c > >>> index 1284173..193cf9f 100644 > >>> --- a/target-i386/translate.c > >>> +++ b/target-i386/translate.c > >>> @@ -8000,7 +8000,7 @@ static inline void gen_intermediate_code_internal(X86CPU *cpu, > >>> if (bp->pc == pc_ptr && > >>> !((bp->flags & BP_CPU) && (tb->flags & HF_RF_MASK))) { > >>> gen_debug(dc, pc_ptr - dc->cs_base); > >>> - break; > >>> + goto done_generating; > >> This makes sense to me. > >> But I don't see why you don't just "break" like the other instruction in > >> this loop? > > Single break will just exit the breakpoints iteration loop. I'll need an additional flag > > to break the translation loop. ARM does the same thing, anyway :) > > Yes that's what I mentioned. > > > >>> } > >>> } > >>> } > >>> @@ -8049,6 +8049,7 @@ static inline void gen_intermediate_code_internal(X86CPU *cpu, > >>> break; > >>> } > >>> } > >>> +done_generating: > >>> if (tb->cflags & CF_LAST_IO) > >>> gen_io_end(); > >> Is there any reason why you don't jump over this two lines in case of a > >> breakpoint? > > Shouldn't we switch off can_do_io flag if it was switched on? > > Yes but can we switch on can_do_io if we have a breakpoint? > > The code is not shown in this patch but there is: > > if (num_insns + 1 == max_insns && (tb->cflags & CF_LAST_IO)) > gen_io_start(); > > I think you can't reach this code if you exit the translation loop? This is not the only gen_io_start call. It is called from some of the instructions' translation functions, that could precede the breakpoint. Pavel Dovgalyuk