From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andre Przywara Subject: Re: [PATCH v2 0/7] KVM: arm/arm64: gsi routing support Date: Thu, 9 Jul 2015 16:25:50 +0100 Message-ID: <559E927E.8040403@arm.com> References: <1436430137-24205-1-git-send-email-eric.auger@linaro.org> <023601d0ba54$c4d6e020$4e84a060$@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "eric.auger@st.com" , "kvm@vger.kernel.org" , Marc Zyngier , "pbonzini@redhat.com" , "kvmarm@lists.cs.columbia.edu" To: Pavel Fedin , "linux-arm-kernel@lists.infradead.org" Return-path: In-Reply-To: <023601d0ba54$c4d6e020$4e84a060$@samsung.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu List-Id: kvm.vger.kernel.org Hi Pavel, On 09/07/15 15:37, Pavel Fedin wrote: > Hello! > >> v1 -> v2: >> - user API changed: >> x devid id passed in kvm_irq_routing_msi >> x kept the new routing entry type: KVM_IRQ_ROUTING_EXTENDED_MSI > > Andre, you never replied to my last comment to the previous series. Oh dear, my draft folder again :-( Sorry for that! > Are you going to do the same > change in your MSI API? Otherwise: > 1. KVM_IRQ_LINE - we have completely own convention. Well, this was already done before us, we > cannot fix it. > 2. KVM_SIGNAL_MSI - we use VALID_DEVID flag plus devid Yes, because there is already a flag value and no other way to specify this, in contrast to ... > 3. KVM_SET_GSI_ROUTING - we use KVM_IRQ_ROUTING_EXTENDED_MSI plus devid Here we already have a type field with some users, so lets piggy-back on this. Both ioctl extensions are coupled with a per-VM capability to let userland know that it needs to provide a device ID. > Don't (2) and (3) together still look bad? Since we agreed on not using flags, i would suggest to > have KVM_SIGNAL_EXTENDED_MSI counterpart, which also doesn't use flags. Using flags on its own (without an explicit capability) is what I opposed against, not flags in general. After all, that's what they are meant for, right? In case of KVM_SET_GSI_ROUTING it just seems awkward to me to use a flag when a different type would do as well. But after all, I don't have a strong opinion on that matter, so if others prefer using a flag I am also fine with that. Poka, Andre. > I know, we were already talking about it, so, if this gets ignored for the second time, i assume > the Architects decided that fancy APIs are cool, and i promise to stop this. > > Kind regards, > Pavel Fedin > Expert Engineer > Samsung Electronics Research center Russia >