From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38732) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XGohl-0003yx-4y for qemu-devel@nongnu.org; Mon, 11 Aug 2014 08:28:07 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XGohf-00028O-81 for qemu-devel@nongnu.org; Mon, 11 Aug 2014 08:28:01 -0400 Received: from mail-wi0-f174.google.com ([209.85.212.174]:55018) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XGohf-000286-29 for qemu-devel@nongnu.org; Mon, 11 Aug 2014 08:27:55 -0400 Received: by mail-wi0-f174.google.com with SMTP id d1so4140331wiv.13 for ; Mon, 11 Aug 2014 05:27:54 -0700 (PDT) Message-ID: <53E8B6C5.5020106@linaro.org> Date: Mon, 11 Aug 2014 14:27:49 +0200 From: Eric Auger MIME-Version: 1.0 References: <1407594349-9291-1-git-send-email-eric.auger@linaro.org> <1407594349-9291-9-git-send-email-eric.auger@linaro.org> <53E88EC4.9040803@suse.de> <53E8B15A.6080703@linaro.org> <53E8B195.5040808@suse.de> In-Reply-To: <53E8B195.5040808@suse.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5 08/10] hw/intc/arm_gic_kvm: advertise irqfd List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alexander Graf , eric.auger@st.com, christoffer.dall@linaro.org, qemu-devel@nongnu.org, kim.phillips@freescale.com, a.rigo@virtualopensystems.com Cc: peter.maydell@linaro.org, patches@linaro.org, joel.schopp@amd.com, will.deacon@arm.com, stuart.yoder@freescale.com, Bharat.Bhushan@freescale.com, alex.williamson@redhat.com, a.motakis@virtualopensystems.com, kvmarm@lists.cs.columbia.edu On 08/11/2014 02:05 PM, Alexander Graf wrote: > > On 11.08.14 14:04, Eric Auger wrote: >> On 08/11/2014 11:37 AM, Alexander Graf wrote: >>> On 09.08.14 16:25, Eric Auger wrote: >>>> set kvm_irqfds_allowed >>>> >>>> Signed-off-by: Eric Auger >>>> --- >>>> hw/intc/arm_gic_kvm.c | 2 ++ >>>> 1 file changed, 2 insertions(+) >>>> >>>> diff --git a/hw/intc/arm_gic_kvm.c b/hw/intc/arm_gic_kvm.c >>>> index 5038885..08b7bf9 100644 >>>> --- a/hw/intc/arm_gic_kvm.c >>>> +++ b/hw/intc/arm_gic_kvm.c >>>> @@ -576,6 +576,8 @@ static void kvm_arm_gic_realize(DeviceState *dev, >>>> Error **errp) >>>> KVM_DEV_ARM_VGIC_GRP_ADDR, >>>> KVM_VGIC_V2_ADDR_TYPE_CPU, >>>> s->dev_fd); >>>> + >>>> + kvm_irqfds_allowed = true; >>> Is this always true? If it is, why not enable it separately while making >>> vhost-net work for example? >> Hi Alex, >> >> yes I think so. As soon as KVM is enabled, KVM/arm would enable >> injection though irqfd. Defintively makes sense to test it with >> vhost-net too. Well a matter of priority ;-) > > More a matter of accuracy. What if you use new QEMU on old KVM which > does have in-kernel GIC support, but no irqfd support? Hi Alex, VFIO device code also calls kvm_check_extension(kvm_state, KVM_CAP_IRQFD_RESAMPLE) which would return false if IRQFD is not enabled in old kernels. But with respect to vhost-net irqfd usage I cannot comment yet and you may be right ;-) Best Regards Eric > > > Alex >