From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 8/9] KVM: x86: Add EOI exit bitmap inference Date: Fri, 7 Aug 2015 12:16:30 +0200 Message-ID: <55C4857E.5040306@redhat.com> References: <1438788228-34856-1-git-send-email-pbonzini@redhat.com> <1438788228-34856-9-git-send-email-pbonzini@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: Steve Rutherford , "rkrcmar@redhat.com" To: "Wu, Feng" , "linux-kernel@vger.kernel.org" , "kvm@vger.kernel.org" Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 07/08/2015 09:46, Wu, Feng wrote: > If I understand it correctly, here you reserve the low part of the routing > table, and insert entries with KVM_IRQ_ROUTING_MSI type in them, > then you use this as a hint to KVM to set the EOI bit map. I have two > concerns: > > - Currently, GSI 2 is used for MSI routing, I want to make sure after this > patch, whether GSI 2 can still be used for _real_ MSI routing, if it can, > does everything work correctly? The patch has no effect if you use the in-kernel IOAPIC. If you use a userspace IOAPIC you won't be able to use GSI 2 for MSI routing because it falls in the reserved range. > - Now, KVM_IRQ_ROUTING_MSI and KVM_IRQ_ROUTING_IRQCHIP > type entries cannot share the same map[gsi] (pls refer to the following > code), so where should be the IOAPIC entries exist in the map[] array? With split irqchip, only KVM_IRQ_ROUTING_MSI is used. Does this answer your question? Paolo > static int setup_routing_entry(struct kvm_irq_routing_table *rt, > struct kvm_kernel_irq_routing_entry *e, > const struct kvm_irq_routing_entry *ue) > { > > ...... > > /* > * Do not allow GSI to be mapped to the same irqchip more than once. > * Allow only one to one mapping between GSI and MSI. > */ > hlist_for_each_entry(ei, &rt->map[ue->gsi], link) > if (ei->type == KVM_IRQ_ROUTING_MSI || > ue->type == KVM_IRQ_ROUTING_MSI || > ue->u.irqchip.irqchip == ei->irqchip.irqchip) > return r; > > ...... > }