Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753901AbZKAWtE (ORCPT ); Sun, 1 Nov 2009 17:49:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753754AbZKAWtD (ORCPT ); Sun, 1 Nov 2009 17:49:03 -0500 Received: from mail-ew0-f228.google.com ([209.85.219.228]:45369 "EHLO mail-ew0-f228.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753864AbZKAWtD (ORCPT ); Sun, 1 Nov 2009 17:49:03 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=p/n3Kmn6rG1i6VZ0+s/5cTXxlaaHBeapRMD8Vodgv4GZ9RxCeZnCn/x0x/erxWMkNB UBIzklHX3eWzPQ2ME07Blu0yGggfl1MsZPrav1Qsfu7j37rJIHWK8bEoB+aw+TzLUztC puJqkto1AAPkruAN88ASxa/oQ8hz+mbnxUk3Q= Date: Sun, 1 Nov 2009 23:49:06 +0100 From: Frederic Weisbecker To: Jan Kiszka Cc: Ingo Molnar , LKML , Prasad , Alan Stern , Peter Zijlstra , Arnaldo Carvalho de Melo , Steven Rostedt , Jiri Slaby , Li Zefan , Avi Kivity , Paul Mackerras , Mike Galbraith , Masami Hiramatsu , Paul Mundt Subject: Re: [PATCH 4/6] hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events Message-ID: <20091101224904.GC5263@nowhere> References: <4AE55B1B.2030006@web.de> <1257109753-6464-5-git-send-email-fweisbec@gmail.com> <4AEE06FF.9080807@web.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4AEE06FF.9080807@web.de> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2775 Lines: 96 On Sun, Nov 01, 2009 at 11:09:03PM +0100, Jan Kiszka wrote: > Frederic Weisbecker wrote: > [...] > > @@ -94,6 +87,12 @@ static inline void hw_breakpoint_disable(void) > > set_debugreg(0UL, 3); > > } > > > > +#ifdef CONFIG_KVM > > +extern void hw_breakpoint_restore(void); > > +#else > > +static inline void hw_breakpoint_restore(void) { } > > +#endif > > + > > Hmm, if this shall become a KVM-only API, why the empty wrapper? Right, this is an odd reflex. > [...] > > -void arch_flush_thread_hw_breakpoint(struct task_struct *tsk) > > +#ifdef CONFIG_KVM > > +void hw_breakpoint_restore(void) > > { > > - int i; > > - struct thread_struct *thread = &(tsk->thread); > > - > > - thread->debugreg7 = 0; > > - for (i = 0; i < HBP_NUM; i++) > > - thread->debugreg[i] = 0; > > + set_debugreg(__get_cpu_var(cpu_debugreg[0]), 0); > > + set_debugreg(__get_cpu_var(cpu_debugreg[1]), 1); > > + set_debugreg(__get_cpu_var(cpu_debugreg[2]), 2); > > + set_debugreg(__get_cpu_var(cpu_debugreg[3]), 3); > > + set_debugreg(current->thread.debugreg6, 6); > > + set_debugreg(__get_cpu_var(dr7), 7); > > } > > +#endif > > EXPORT_SYMBOL_GPL(hw_breakpoint_restore); > > as KVM can be built as module. Indeed. > [...] > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > > index fc2974a..32d7bca 100644 > > --- a/arch/x86/kvm/x86.c > > +++ b/arch/x86/kvm/x86.c > > @@ -42,6 +42,7 @@ > > #define CREATE_TRACE_POINTS > > #include "trace.h" > > > > +#include > > #include > > #include > > #include > > @@ -3643,14 +3644,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run) > > trace_kvm_entry(vcpu->vcpu_id); > > kvm_x86_ops->run(vcpu, kvm_run); > > > > - if (unlikely(vcpu->arch.switch_db_regs || test_thread_flag(TIF_DEBUG))) { > > - set_debugreg(current->thread.debugreg[0], 0); > > - set_debugreg(current->thread.debugreg[1], 1); > > - set_debugreg(current->thread.debugreg[2], 2); > > - set_debugreg(current->thread.debugreg[3], 3); > > - set_debugreg(current->thread.debugreg6, 6); > > - set_debugreg(current->thread.debugreg7, 7); > > - } > > + if (unlikely(vcpu->arch.switch_db_regs || test_thread_flag(TIF_DEBUG))) > > + hw_breakpoint_restore(); > > TIF_DEBUG is only set on active ptrace hw-breakpoints, thus we miss > other types here, right? (Note: arch.switch_db_regs is guest-related, > thus does not help in this regard.) > > Jan > True :) Thanks a lot for this review, I'm going to fix that quickly. -- 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/