From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH v4] KVM: PPC: BOOKE: Emulate debug registers and exception Date: Thu, 28 Aug 2014 10:44:33 +0200 Message-ID: <53FEEBF1.6090704@suse.de> References: <1407920984-27555-1-git-send-email-Bharat.Bhushan@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, scottwood@freescale.com, stuart.yoder@freescale.com To: Bharat Bhushan , kvm-ppc@vger.kernel.org Return-path: Received: from cantor2.suse.de ([195.135.220.15]:50775 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936276AbaH1Ioh (ORCPT ); Thu, 28 Aug 2014 04:44:37 -0400 In-Reply-To: <1407920984-27555-1-git-send-email-Bharat.Bhushan@freescale.com> Sender: kvm-owner@vger.kernel.org List-ID: On 13.08.14 11:09, Bharat Bhushan wrote: > This patch emulates debug registers and debug exception > to support guest using debug resource. This enables running > gdb/kgdb etc in guest. > > On BOOKE architecture we cannot share debug resources between QEMU and > guest because: > When QEMU is using debug resources then debug exception must > be always enabled. To achieve this we set MSR_DE and also set > MSRP_DEP so guest cannot change MSR_DE. > > When emulating debug resource for guest we want guest > to control MSR_DE (enable/disable debug interrupt on need). > > So above mentioned two configuration cannot be supported > at the same time. So the result is that we cannot share > debug resources between QEMU and Guest on BOOKE architecture. > > In the current design QEMU gets priority over guest, this means that if > QEMU is using debug resources then guest cannot use them and if guest is > using debug resource then QEMU can overwrite them. > > Signed-off-by: Bharat Bhushan Thanks, applied to kvm-ppc-queue. Alex