From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42980) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XhCzj-0006Cq-9w for qemu-devel@nongnu.org; Thu, 23 Oct 2014 03:39:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XhCze-00049O-4T for qemu-devel@nongnu.org; Thu, 23 Oct 2014 03:39:39 -0400 Received: from greensocs.com ([178.33.234.66]:56616) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XhCzd-00049G-NA for qemu-devel@nongnu.org; Thu, 23 Oct 2014 03:39:34 -0400 Message-ID: <5448B0B3.9040702@greensocs.com> Date: Thu, 23 Oct 2014 09:39:31 +0200 From: Frederic Konrad MIME-Version: 1.0 References: <20141022113831.9548.36452.stgit@PASHA-ISP> <5447A8BB.1060707@greensocs.com> <000901cfee86$3c9f1280$b5dd3780$@Dovgaluk@ispras.ru> In-Reply-To: <000901cfee86$3c9f1280$b5dd3780$@Dovgaluk@ispras.ru> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit 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: Pavel Dovgaluk , qemu-devel@nongnu.org Cc: pbonzini@redhat.com, zealot351@gmail.com, maria.klimushenkova@ispras.ru, mark.burton@greensocs.com, batuzovk@ispras.ru 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? Fred > >>> gen_tb_end(tb, num_insns); >>> >>> >> I'll give it a try later and I'll let you know. > Thanks. > > Pavel Dovgalyuk > >