Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753576AbbGBItB (ORCPT ); Thu, 2 Jul 2015 04:49:01 -0400 Received: from foss.arm.com ([217.140.101.70]:48810 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752016AbbGBIsw (ORCPT ); Thu, 2 Jul 2015 04:48:52 -0400 Date: Thu, 2 Jul 2015 09:48:47 +0100 From: Will Deacon To: Alex =?iso-8859-1?Q?Benn=E9e?= Cc: "kvm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "kvmarm@lists.cs.columbia.edu" , "christoffer.dall@linaro.org" , Marc Zyngier , "peter.maydell@linaro.org" , "agraf@suse.de" , "drjones@redhat.com" , "pbonzini@redhat.com" , "zhichao.huang@linaro.org" , "jan.kiszka@siemens.com" , "dahi@linux.vnet.ibm.com" , "r65777@freescale.com" , "bp@suse.de" , Gleb Natapov , Jonathan Corbet , Catalin Marinas , Lorenzo Pieralisi , Ingo Molnar , Peter Zijlstra , "open list:DOCUMENTATION" , open list , "open list:ABI/API" Subject: Re: [PATCH v7 09/11] KVM: arm64: guest debug, HW assisted debug support Message-ID: <20150702084847.GB3418@arm.com> References: <1435775343-20034-1-git-send-email-alex.bennee@linaro.org> <1435775343-20034-10-git-send-email-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1435775343-20034-10-git-send-email-alex.bennee@linaro.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2054 Lines: 56 Hi Alex, On Wed, Jul 01, 2015 at 07:29:01PM +0100, Alex Benn?e wrote: > This adds support for userspace to control the HW debug registers for > guest debug. In the debug ioctl we copy an IMPDEF registers into a new > register set called host_debug_state. > > We use the recently introduced vcpu parameter debug_ptr to select which > register set is copied into the real registers when world switch occurs. > > I've made some helper functions from hw_breakpoint.c more widely > available for re-use. > > As with single step we need to tweak the guest registers to enable the > exceptions so we need to save and restore those bits. > > Two new capabilities have been added to the KVM_EXTENSION ioctl to allow > userspace to query the number of hardware break and watch points > available on the host hardware. > > Signed-off-by: Alex Benn?e > Reviewed-by: Christoffer Dall [...] > diff --git a/arch/arm64/kernel/hw_breakpoint.c b/arch/arm64/kernel/hw_breakpoint.c > index e7d934d..ac07f2a 100644 > --- a/arch/arm64/kernel/hw_breakpoint.c > +++ b/arch/arm64/kernel/hw_breakpoint.c > @@ -50,13 +50,13 @@ static int core_num_brps; > static int core_num_wrps; > > /* Determine number of BRP registers available. */ > -static int get_num_brps(void) > +int get_num_brps(void) > { > return ((read_cpuid(ID_AA64DFR0_EL1) >> 12) & 0xf) + 1; > } > > /* Determine number of WRP registers available. */ > -static int get_num_wrps(void) > +int get_num_wrps(void) > { > return ((read_cpuid(ID_AA64DFR0_EL1) >> 20) & 0xf) + 1; > } Sorry, just noticed this, but we already have a public interface for figuring these numbers out as required by perf. Can't you use hw_breakpoint_slots(...) instead of exposing these internal helpers? Will -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/