From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexander Graf Subject: Re: [PATCH 5/6] KVM: PPC: BOOKE: Allow guest to change MSR_DE Date: Tue, 29 Jul 2014 16:05:13 +0200 Message-ID: <53D7AA19.1020405@suse.de> References: <1405067941-27134-1-git-send-email-Bharat.Bhushan@freescale.com> <1405067941-27134-6-git-send-email-Bharat.Bhushan@freescale.com> <1406584878.29414.166.camel@snotra.buserror.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm-ppc@vger.kernel.org, kvm@vger.kernel.org, stuart.yoder@freescale.com To: Scott Wood , Bharat Bhushan Return-path: In-Reply-To: <1406584878.29414.166.camel@snotra.buserror.net> Sender: kvm-ppc-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 29.07.14 00:01, Scott Wood wrote: > On Fri, 2014-07-11 at 14:09 +0530, Bharat Bhushan wrote: >> When userspace is debugging guest then MSR_DE is always set and >> MSRP_DEP is set so that guest cannot change MSR_DE. >> Guest debug resources are not yet emulated, So there seems no reason >> we should stop guest controlling MSR_DE. >> Also a followup patch will enable debug emulation and that requires >> guest to control MSR_DE. > Why does it matter whether we emulate debug resources? We still don't > want the guest to be able to clear MSR[DE] and thus break host debug. The patch description is misleading. This patch changes the default of DEP to "guest controlled" when it boots up. Once QEMU wants control over the debug registers, it gets switched to "QEMU controlled" (that code is already there). Alex