From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marc Zyngier Subject: Re: [PATCH 3/5] irqchip/gic-v2: Parse and export virtual GIC information Date: Wed, 10 Feb 2016 14:46:02 +0000 Message-ID: <56BB4D2A.1030903@arm.com> References: <1454950049-741-1-git-send-email-julien.grall@arm.com> <1454950049-741-4-git-send-email-julien.grall@arm.com> <20160209204914.GE5171@cbox> <56BB46DC.7080202@arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id DC75149AF2 for ; Wed, 10 Feb 2016 09:40:17 -0500 (EST) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id ROEbykeevb06 for ; Wed, 10 Feb 2016 09:40:16 -0500 (EST) Received: from foss.arm.com (foss.arm.com [217.140.101.70]) by mm01.cs.columbia.edu (Postfix) with ESMTP id A9C8549A8E for ; Wed, 10 Feb 2016 09:40:16 -0500 (EST) In-Reply-To: <56BB46DC.7080202@arm.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 To: Julien Grall , Christoffer Dall Cc: al.stone@linaro.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, fu.wei@linaro.org, Thomas Gleixner , kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Jason Cooper List-Id: kvmarm@lists.cs.columbia.edu On 10/02/16 14:19, Julien Grall wrote: > Hi Christoffer, > > On 09/02/16 20:49, Christoffer Dall wrote: >>> +static void __init gic_acpi_setup_kvm_info(void) >>> +{ >>> + gic_v2_kvm_info.type = GIC_V2; >>> + >>> + gic_v2_kvm_info.maint_irq = acpi_register_gsi(NULL, >>> + acpi_data.maint_irq, >>> + acpi_data.maint_irq_mode, >>> + ACPI_ACTIVE_HIGH); >>> + gic_v2_kvm_info.vctrl_base = acpi_data.vctrl_base; >>> + if (gic_v2_kvm_info.vctrl_base) >>> + gic_v2_kvm_info.vctrl_size = SZ_8K; >>> + >>> + gic_v2_kvm_info.vcpu_base = acpi_data.vcpu_base; >>> + if (gic_v2_kvm_info.vcpu_base) >>> + gic_v2_kvm_info.vcpu_size = SZ_8K; >> >> why are the sizes hard-coded to 8K in this case? > > The MADT only provides the base addresses and not the size. The default > value has been chosen based on the GICv2 spec (ARM IHI 0048B.b) > * GICV: See 5.5 > * GICH: I can't find again the section about it. But the example > bindings in > Documents/devicetree/bindings/interrupt-controller/arm,gic.txt uses 8K. > > I will add a comment in the code explaining where the 8K come from. The GICH size can be found in the GIC400 TRM: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0471b/CHDBJDCB.html The first 4kB are banked per CPU, while the next 4kB are exposing all CPUs, each in a 512 bytes window. We don't give a damn about the second page, but hey, it is there... Of course, this is GIC400, not the architecture spec. So maybe considering a 4kB size would be better, just in case someone is braindead enough to produce another GICv2 implementation without the aliases... M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Wed, 10 Feb 2016 14:46:02 +0000 Subject: [PATCH 3/5] irqchip/gic-v2: Parse and export virtual GIC information In-Reply-To: <56BB46DC.7080202@arm.com> References: <1454950049-741-1-git-send-email-julien.grall@arm.com> <1454950049-741-4-git-send-email-julien.grall@arm.com> <20160209204914.GE5171@cbox> <56BB46DC.7080202@arm.com> Message-ID: <56BB4D2A.1030903@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 10/02/16 14:19, Julien Grall wrote: > Hi Christoffer, > > On 09/02/16 20:49, Christoffer Dall wrote: >>> +static void __init gic_acpi_setup_kvm_info(void) >>> +{ >>> + gic_v2_kvm_info.type = GIC_V2; >>> + >>> + gic_v2_kvm_info.maint_irq = acpi_register_gsi(NULL, >>> + acpi_data.maint_irq, >>> + acpi_data.maint_irq_mode, >>> + ACPI_ACTIVE_HIGH); >>> + gic_v2_kvm_info.vctrl_base = acpi_data.vctrl_base; >>> + if (gic_v2_kvm_info.vctrl_base) >>> + gic_v2_kvm_info.vctrl_size = SZ_8K; >>> + >>> + gic_v2_kvm_info.vcpu_base = acpi_data.vcpu_base; >>> + if (gic_v2_kvm_info.vcpu_base) >>> + gic_v2_kvm_info.vcpu_size = SZ_8K; >> >> why are the sizes hard-coded to 8K in this case? > > The MADT only provides the base addresses and not the size. The default > value has been chosen based on the GICv2 spec (ARM IHI 0048B.b) > * GICV: See 5.5 > * GICH: I can't find again the section about it. But the example > bindings in > Documents/devicetree/bindings/interrupt-controller/arm,gic.txt uses 8K. > > I will add a comment in the code explaining where the 8K come from. The GICH size can be found in the GIC400 TRM: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0471b/CHDBJDCB.html The first 4kB are banked per CPU, while the next 4kB are exposing all CPUs, each in a 512 bytes window. We don't give a damn about the second page, but hey, it is there... Of course, this is GIC400, not the architecture spec. So maybe considering a 4kB size would be better, just in case someone is braindead enough to produce another GICv2 implementation without the aliases... M. -- Jazz is not dead. It just smells funny... From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752060AbcBJOqJ (ORCPT ); Wed, 10 Feb 2016 09:46:09 -0500 Received: from foss.arm.com ([217.140.101.70]:47952 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750865AbcBJOqG (ORCPT ); Wed, 10 Feb 2016 09:46:06 -0500 Subject: Re: [PATCH 3/5] irqchip/gic-v2: Parse and export virtual GIC information To: Julien Grall , Christoffer Dall References: <1454950049-741-1-git-send-email-julien.grall@arm.com> <1454950049-741-4-git-send-email-julien.grall@arm.com> <20160209204914.GE5171@cbox> <56BB46DC.7080202@arm.com> Cc: kvmarm@lists.cs.columbia.edu, fu.wei@linaro.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, wei@redhat.com, al.stone@linaro.org, Thomas Gleixner , Jason Cooper From: Marc Zyngier X-Enigmail-Draft-Status: N1110 Organization: ARM Ltd Message-ID: <56BB4D2A.1030903@arm.com> Date: Wed, 10 Feb 2016 14:46:02 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Icedove/38.5.0 MIME-Version: 1.0 In-Reply-To: <56BB46DC.7080202@arm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/02/16 14:19, Julien Grall wrote: > Hi Christoffer, > > On 09/02/16 20:49, Christoffer Dall wrote: >>> +static void __init gic_acpi_setup_kvm_info(void) >>> +{ >>> + gic_v2_kvm_info.type = GIC_V2; >>> + >>> + gic_v2_kvm_info.maint_irq = acpi_register_gsi(NULL, >>> + acpi_data.maint_irq, >>> + acpi_data.maint_irq_mode, >>> + ACPI_ACTIVE_HIGH); >>> + gic_v2_kvm_info.vctrl_base = acpi_data.vctrl_base; >>> + if (gic_v2_kvm_info.vctrl_base) >>> + gic_v2_kvm_info.vctrl_size = SZ_8K; >>> + >>> + gic_v2_kvm_info.vcpu_base = acpi_data.vcpu_base; >>> + if (gic_v2_kvm_info.vcpu_base) >>> + gic_v2_kvm_info.vcpu_size = SZ_8K; >> >> why are the sizes hard-coded to 8K in this case? > > The MADT only provides the base addresses and not the size. The default > value has been chosen based on the GICv2 spec (ARM IHI 0048B.b) > * GICV: See 5.5 > * GICH: I can't find again the section about it. But the example > bindings in > Documents/devicetree/bindings/interrupt-controller/arm,gic.txt uses 8K. > > I will add a comment in the code explaining where the 8K come from. The GICH size can be found in the GIC400 TRM: http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0471b/CHDBJDCB.html The first 4kB are banked per CPU, while the next 4kB are exposing all CPUs, each in a 512 bytes window. We don't give a damn about the second page, but hey, it is there... Of course, this is GIC400, not the architecture spec. So maybe considering a 4kB size would be better, just in case someone is braindead enough to produce another GICv2 implementation without the aliases... M. -- Jazz is not dead. It just smells funny...