From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753834AbaF0NSU (ORCPT ); Fri, 27 Jun 2014 09:18:20 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:35873 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752604AbaF0NSS (ORCPT ); Fri, 27 Jun 2014 09:18:18 -0400 Date: Fri, 27 Jun 2014 14:17:48 +0100 From: Will Deacon To: Marc Zyngier Cc: "kvmarm@lists.cs.columbia.edu" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Catalin Marinas , Thomas Gleixner , "eric.auger@linaro.org" , Christoffer Dall Subject: Re: [RFC PATCH 4/9] irqchip: GIC: add support for forwarded interrupts Message-ID: <20140627131748.GT26276@arm.com> References: <1403688530-23273-1-git-send-email-marc.zyngier@arm.com> <1403688530-23273-5-git-send-email-marc.zyngier@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1403688530-23273-5-git-send-email-marc.zyngier@arm.com> 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 Hi Marc, On Wed, Jun 25, 2014 at 10:28:45AM +0100, Marc Zyngier wrote: > Now that we've switched to EOImode == 1, prevent a forwarded interrupt > from being deactivated after its priority has been dropped. > > Also add support for the interrupt state to be saved/restored. > > Signed-off-by: Marc Zyngier > --- > drivers/irqchip/irq-gic.c | 48 +++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 42 insertions(+), 6 deletions(-) [...] > +static void gic_irq_set_fwd_state(struct irq_data *d, u32 val, u32 mask) > +{ > + if (mask & IRQ_FWD_STATE_PENDING) > + gic_poke_irq(d, (val & IRQ_FWD_STATE_PENDING) ? GIC_DIST_ENABLE_SET : GIC_DIST_ENABLE_CLEAR); > + if (mask & IRQ_FWD_STATE_ACTIVE) > + gic_poke_irq(d, (val & IRQ_FWD_STATE_ACTIVE) ? GIC_DIST_ACTIVE_SET : GIC_DIST_ACTIVE_CLEAR); > + if (mask & IRQ_FWD_STATE_MASKED) > + gic_poke_irq(d, (val & IRQ_FWD_STATE_MASKED) ? GIC_DIST_ENABLE_CLEAR : GIC_DIST_ENABLE_SET); Given that this isn't atomic and KVM only cares about ACTIVE, why not change mask to be a single state only? Renumbering the states so that's not bits would help to enforce this (i.e. make IRQ_FWD_STATE_ACTIVE 0, PENDING 1, ...). That would also allow you to switch on the state and return early. > +static u32 gic_irq_get_fwd_state(struct irq_data *d, u32 mask) > +{ > + u32 val = 0; > + > + if (mask & IRQ_FWD_STATE_PENDING && gic_peek_irq(d, GIC_DIST_ENABLE_SET)) > + val |= IRQ_FWD_STATE_PENDING; > + if (mask & IRQ_FWD_STATE_ACTIVE && gic_peek_irq(d, GIC_DIST_ACTIVE_SET)) > + val |= IRQ_FWD_STATE_ACTIVE; > + if (mask & IRQ_FWD_STATE_MASKED && !gic_peek_irq(d, GIC_DIST_ENABLE_SET)) > + val |= IRQ_FWD_STATE_MASKED; *and* you could peek GIC_DIST_ENABLE_SET in one place here. Will