From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36667) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dNgrE-0003mw-Pd for qemu-devel@nongnu.org; Wed, 21 Jun 2017 10:43:50 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dNgrB-0003BH-N4 for qemu-devel@nongnu.org; Wed, 21 Jun 2017 10:43:48 -0400 Received: from mail-wr0-x22a.google.com ([2a00:1450:400c:c0c::22a]:35968) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dNgrB-0003Aw-Ey for qemu-devel@nongnu.org; Wed, 21 Jun 2017 10:43:45 -0400 Received: by mail-wr0-x22a.google.com with SMTP id c11so82539826wrc.3 for ; Wed, 21 Jun 2017 07:43:45 -0700 (PDT) References: <8760fqorbp.fsf@frigg.lan> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: Date: Wed, 21 Jun 2017 15:44:22 +0100 Message-ID: <87mv91tn7d.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] Tracing guest virtual addresses List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Jayanto Minocha , QEMU Developers Peter Maydell writes: > On 20 June 2017 at 12:02, Lluís Vilanova wrote: >> Jayanto Minocha writes: >>> But that is only used to instrument the cpu_ld/cpu_st macros, which is only >>> called in the case of a tlb miss. >> >>> I've been going over the archives, and it looks like I need to instrument >>> tcg_out_tlb_load. Am I on the right path ? >> >> That event should trace all guest memory accesses performed by the CPU. If you >> found any case where this does not hold, it is likely a bug and I'd appreciate >> it if you can point me to the smallest possible failing example. > > Does it catch memory accesses that are performed via helper functions, > or only ones done by inline TCG code? AFAICT it inserts a helper call on the TCG ld/st ops. I wonder why not just ensure we always take the slow path and put the helpers in the access functions there? You could even apply an address mask if you only want to look at certain address ranges. > > thanks > -- PMM -- Alex Bennée