Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754501AbbHJIpA (ORCPT ); Mon, 10 Aug 2015 04:45:00 -0400 Received: from mail-wi0-f177.google.com ([209.85.212.177]:34199 "EHLO mail-wi0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753258AbbHJIo6 (ORCPT ); Mon, 10 Aug 2015 04:44:58 -0400 Message-ID: <55C8645E.6060505@linaro.org> Date: Mon, 10 Aug 2015 10:44:14 +0200 From: Eric Auger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.8.0 MIME-Version: 1.0 To: Alex Williamson CC: eric.auger@st.com, feng.wu@intel.com, pbonzini@redhat.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, avi.kivity@gmail.com, mtosatti@redhat.com, joro@8bytes.org, marc.zyngier@arm.com, christoffer.dall@linaro.org, linux-kernel@vger.kernel.org, patches@linaro.org Subject: Re: [PATCH v4 5/5] KVM: eventfd: add irq bypass consumer management References: <1438622444-25444-1-git-send-email-eric.auger@linaro.org> <1438622444-25444-6-git-send-email-eric.auger@linaro.org> <1438978155.4023.263.camel@redhat.com> In-Reply-To: <1438978155.4023.263.camel@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3176 Lines: 99 Hi Alex, On 08/07/2015 10:09 PM, Alex Williamson wrote: > On Mon, 2015-08-03 at 19:20 +0200, Eric Auger wrote: >> This patch adds the registration/unregistration of an >> irq_bypass_consumer on irqfd assignment/deassignment. >> >> Signed-off-by: Eric Auger >> Signed-off-by: Feng Wu >> >> --- >> >> v2 -> v3 (Feng Wu): >> - Use kvm_arch_irq_bypass_start >> - Remove kvm_arch_irq_bypass_update >> - Add member 'struct irq_bypass_producer *producer' in >> 'struct kvm_kernel_irqfd', it is needed by posted interrupt. >> - Remove 'irq_bypass_unregister_consumer' in kvm_irqfd_deassign() >> >> v1 -> v2: >> - populate of kvm and gsi removed >> - unregister the consumer on irqfd_shutdown >> --- >> include/linux/kvm_irqfd.h | 2 ++ >> virt/kvm/eventfd.c | 10 ++++++++++ >> 2 files changed, 12 insertions(+) >> >> diff --git a/include/linux/kvm_irqfd.h b/include/linux/kvm_irqfd.h >> index f926b39..0c1de05 100644 >> --- a/include/linux/kvm_irqfd.h >> +++ b/include/linux/kvm_irqfd.h >> @@ -64,6 +64,8 @@ struct kvm_kernel_irqfd { >> struct list_head list; >> poll_table pt; >> struct work_struct shutdown; >> + struct irq_bypass_consumer consumer; >> + struct irq_bypass_producer *producer; >> }; >> >> #endif /* __LINUX_KVM_IRQFD_H */ >> diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c >> index 647ffb8..08855de 100644 >> --- a/virt/kvm/eventfd.c >> +++ b/virt/kvm/eventfd.c >> @@ -35,6 +35,7 @@ >> #include >> #include >> #include >> +#include >> #include >> >> #include >> @@ -140,6 +141,7 @@ irqfd_shutdown(struct work_struct *work) >> /* >> * It is now safe to release the object's resources >> */ >> + irq_bypass_unregister_consumer(&irqfd->consumer); >> eventfd_ctx_put(irqfd->eventfd); >> kfree(irqfd); >> } >> @@ -380,6 +382,14 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) >> */ >> fdput(f); >> >> + irqfd->consumer.token = (void *)irqfd->eventfd; >> + irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer; >> + irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer; >> + irqfd->consumer.stop = kvm_arch_irq_bypass_stop; >> + irqfd->consumer.start = kvm_arch_irq_bypass_start; >> + ret = irq_bypass_register_consumer(&irqfd->consumer); >> + WARN_ON(ret); > > This seems like a lazy way to handle this error. What is the stack > trace from this WARN_ON going to tell us that we didn't already know? > If we get the WARN_ON, it's probably means that an incompatible producer > registered the token first. It means we can't do bypass, but it doesn't > tell us anything about whether bypass is or is not enabled. Wouldn't a > pr_info/debug() suffice for that? Thanks, Sure I will output some more relevant traces. Thanks Eric > > Alex > >> + >> return 0; >> >> fail: > > > -- 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/