From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761513AbXGTMLl (ORCPT ); Fri, 20 Jul 2007 08:11:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753723AbXGTMLe (ORCPT ); Fri, 20 Jul 2007 08:11:34 -0400 Received: from ozlabs.org ([203.10.76.45]:53182 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751758AbXGTMLe (ORCPT ); Fri, 20 Jul 2007 08:11:34 -0400 Subject: [PATCH 1/3] lguest: fix sense if IF flag on interrupt injection From: Rusty Russell To: Linus Torvalds Cc: lkml - Kernel Mailing List , virtualization Content-Type: text/plain Date: Fri, 20 Jul 2007 22:11:13 +1000 Message-Id: <1184933473.10380.296.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org The sense of the IF bit is backwards in the host interrupt handling. This means we always save "IF=1" on the stack when injecting an interrupt. It turns out this is almost always correct (unless the guest is taking a page fault in an interrupt due to an unpopulated vmalloc mapping), so went unnoticed. Signed-off-by: Rusty Russell --- drivers/lguest/interrupts_and_traps.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff -r 209f5cd5cda5 drivers/lguest/interrupts_and_traps.c --- a/drivers/lguest/interrupts_and_traps.c Fri Jul 20 14:53:40 2007 +1000 +++ b/drivers/lguest/interrupts_and_traps.c Fri Jul 20 21:34:06 2007 +1000 @@ -38,12 +38,12 @@ static void set_guest_interrupt(struct l ss = lg->regs->ss; } - /* We use IF bit in eflags to indicate whether irqs were disabled - (it's always 0, since irqs are enabled when guest is running). */ + /* We use IF bit in eflags to indicate whether irqs were enabled + (it's always 1, since irqs are enabled when guest is running). */ eflags = lg->regs->eflags; - if (get_user(irq_enable, &lg->lguest_data->irq_enabled)) - irq_enable = 0; - eflags |= (irq_enable & X86_EFLAGS_IF); + if (get_user(irq_enable, &lg->lguest_data->irq_enabled) == 0 + && !(irq_enable & X86_EFLAGS_IF)) + eflags &= ~X86_EFLAGS_IF; push_guest_stack(lg, &gstack, eflags); push_guest_stack(lg, &gstack, lg->regs->cs);