From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752849Ab3KSPCt (ORCPT ); Tue, 19 Nov 2013 10:02:49 -0500 Received: from mx1.redhat.com ([209.132.183.28]:4648 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751379Ab3KSPCs (ORCPT ); Tue, 19 Nov 2013 10:02:48 -0500 Message-ID: <528B7D79.6030208@redhat.com> Date: Tue, 19 Nov 2013 16:02:17 +0100 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130923 Thunderbird/17.0.9 MIME-Version: 1.0 To: Dan Aloni CC: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, x86@kernel.org, gleb@redhat.com, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, Muli Ben-Yehuda Subject: Re: [PATCH linux-next 2/2] kvm-x86: emulator: disable kgdb-x86 on fastop and fpe flush References: <1384872810-29492-1-git-send-email-alonid@stratoscale.com> <1384872810-29492-3-git-send-email-alonid@stratoscale.com> In-Reply-To: <1384872810-29492-3-git-send-email-alonid@stratoscale.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 19/11/2013 15:53, Dan Aloni ha scritto: > We have seen that when kvm-unit-tests runs with kgdb enabled, the > kernel halts on the debugger during the KVM x86 instruction emulation > that performs a test of a division by zero, and also during fwait. > > This patch adds calls that temporarily disable the debugger trap. > > Signed-off-by: Dan Aloni > Signed-off-by: Muli Ben-Yehuda > --- > arch/x86/kvm/emulate.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c > index 07ffca0..05e8509 100644 > --- a/arch/x86/kvm/emulate.c > +++ b/arch/x86/kvm/emulate.c > @@ -24,6 +24,7 @@ > #include "kvm_cache_regs.h" > #include > #include > +#include > #include > > #include "x86.h" > @@ -4438,6 +4439,7 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt) > { > bool fault = false; > > + kgdb_ll_local_disable(); > ctxt->ops->get_fpu(ctxt); > asm volatile("1: fwait \n\t" > "2: \n\t" > @@ -4449,6 +4451,7 @@ static int flush_pending_x87_faults(struct x86_emulate_ctxt *ctxt) > _ASM_EXTABLE(1b, 3b) > : [fault]"+qm"(fault)); > ctxt->ops->put_fpu(ctxt); > + kgdb_ll_local_enable(); > > if (unlikely(fault)) > return emulate_exception(ctxt, MF_VECTOR, 0, false); > @@ -4468,10 +4471,14 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *)) > ulong flags = (ctxt->eflags & EFLAGS_MASK) | X86_EFLAGS_IF; > if (!(ctxt->d & ByteOp)) > fop += __ffs(ctxt->dst.bytes) * FASTOP_SIZE; > + > + kgdb_ll_local_disable(); > asm("push %[flags]; popf; call *%[fastop]; pushf; pop %[flags]\n" > : "+a"(ctxt->dst.val), "+d"(ctxt->src.val), [flags]"+D"(flags), > [fastop]"+S"(fop) > : "c"(ctxt->src2.val)); > + kgdb_ll_local_enable(); > + > ctxt->eflags = (ctxt->eflags & ~EFLAGS_MASK) | (flags & EFLAGS_MASK); > if (!fop) /* exception is returned in fop variable */ > return emulate_de(ctxt); > Acked-by: Paolo Bonzini