From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp05.in.ibm.com (e28smtp05.in.ibm.com [122.248.162.5]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id D9A2C1A003E for ; Tue, 12 Aug 2014 15:18:04 +1000 (EST) Received: from /spool/local by e28smtp05.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 12 Aug 2014 10:48:01 +0530 Received: from d28relay04.in.ibm.com (d28relay04.in.ibm.com [9.184.220.61]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id E875DE001F for ; Tue, 12 Aug 2014 10:49:56 +0530 (IST) Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay04.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s7C5IJYY35586092 for ; Tue, 12 Aug 2014 10:48:20 +0530 Received: from d28av01.in.ibm.com (localhost [127.0.0.1]) by d28av01.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s7C5HuiK023483 for ; Tue, 12 Aug 2014 10:47:57 +0530 Message-ID: <53E9A383.5060009@linux.vnet.ibm.com> Date: Tue, 12 Aug 2014 10:47:55 +0530 From: Madhavan Srinivasan MIME-Version: 1.0 To: Alexander Graf , Benjamin Herrenschmidt Subject: Re: [PATCH v3] powerpc/kvm: support to handle sw breakpoint References: <1406868643-26291-1-git-send-email-maddy@linux.vnet.ibm.com> <53E87023.6080200@suse.de> <1407747061.4508.75.camel@pasglop> <53E889BA.40108@suse.de> In-Reply-To: <53E889BA.40108@suse.de> Content-Type: text/plain; charset=UTF-8 Cc: linuxppc-dev@lists.ozlabs.org, paulus@samba.org, kvm-ppc@vger.kernel.org, kvm@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Monday 11 August 2014 02:45 PM, Alexander Graf wrote: > > On 11.08.14 10:51, Benjamin Herrenschmidt wrote: >> On Mon, 2014-08-11 at 09:26 +0200, Alexander Graf wrote: >>>> diff --git a/arch/powerpc/kvm/emulate.c b/arch/powerpc/kvm/emulate.c >>>> index da86d9b..d95014e 100644 >>>> --- a/arch/powerpc/kvm/emulate.c >>>> +++ b/arch/powerpc/kvm/emulate.c >>> This should be book3s_emulate.c. >> Any reason we can't make that 00dddd00 opcode as breakpoint common to >> all powerpc variants ? > > I can't think of a good reason. We use a hypercall on booke (which traps > into an illegal instruction for pr) today, but I don't think it has to > be that way. > > Given that the user space API allows us to change it dynamically, there > should be nothing blocking us from going with 00dddd00 always. > Kindly correct me if i am wrong. So we can still have a common code in emulate.c to set the env for both HV and pr incase of illegal instruction (i will rebase latest src). But suggestion here to use 00dddd00, in that case current path in embed is kvmppc_handle_exit (booke.c) -> BOOKE_INTERRUPT_HV_PRIV -> emulation_exit -> kvmppc_emulate_instruction, will change to kvmppc_handle_exit (booke.c) -> BOOKE_INTERRUPT_PROGRAM -> if debug instr call emulation_exit else send to guest? Thanks for review regards Maddy > > Alex >