Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753969AbaLDKGR (ORCPT ); Thu, 4 Dec 2014 05:06:17 -0500 Received: from mail-wg0-f45.google.com ([74.125.82.45]:40397 "EHLO mail-wg0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753049AbaLDKGM (ORCPT ); Thu, 4 Dec 2014 05:06:12 -0500 Message-ID: <548031C1.9020701@linaro.org> Date: Thu, 04 Dec 2014 11:04:49 +0100 From: Eric Auger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Christoffer Dall CC: eric.auger@st.com, marc.zyngier@arm.com, linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, alex.williamson@redhat.com, agraf@suse.de, gleb@kernel.org, pbonzini@redhat.com, linux-kernel@vger.kernel.org, patches@linaro.org, a.motakis@virtualopensystems.com Subject: Re: [PATCH] KVM: arm/arm64: vgic: add init entry to VGIC KVM device References: <1417541251-20761-1-git-send-email-eric.auger@linaro.org> <20141203104510.GE17502@cbox> In-Reply-To: <20141203104510.GE17502@cbox> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoffer On 12/03/2014 11:45 AM, Christoffer Dall wrote: > On Tue, Dec 02, 2014 at 06:27:31PM +0100, Eric Auger wrote: >> Since the advent of dynamic initialization of VGIC, this latter is >> initialized very late, on the first vcpu run. This initialization >> could be initiated much earlier by the user, as soon as it has >> provided the requested dimensioning parameters: >> - number of IRQs and number of vCPUs, >> - DIST and CPU interface base address. >> >> One motivation behind being able to initialize the VGIC sooner is >> related to the setup of IRQ injection in VFIO use case. The VFIO >> signaling, especially when used along with irqfd must be set *after* >> vgic initialization to prevent any virtual IRQ injection before >> VGIC initialization. If virtual IRQ injection occurs before the VGIC >> init, the IRQ cannot be injected and subsequent injection is blocked >> due to VFIO completion mechanism (unmask/mask or forward/unforward). >> >> This patch adds a new entry to the VGIC KVM device that allows >> the user to manually request the VGIC init: >> - a new KVM_DEV_ARM_VGIC_GRP_CTRL group is introduced. >> - Its first attribute is KVM_DEV_ARM_VGIC_CTRL_INIT >> >> The rationale behind introducing a group is to be able to add other >> controls later on, if needed. >> >> Obviously, as soon as the init is done, the dimensioning parameters >> cannot be changed. > > you would need to add a check in the vcpu_create path, check added in v2 which I don't > believe we currently have. That may conflict with Andre's series so we > need to coordinate. > > We're also seeing this potentially being useful for migration, so my > feeling is that the GICv3 patches should be rebased on this patch and > this patch should include a check in the vcpu create path. > >> >> Signed-off-by: Eric Auger >> --- >> Documentation/virtual/kvm/devices/arm-vgic.txt | 11 +++++++++++ >> arch/arm/include/uapi/asm/kvm.h | 2 ++ >> arch/arm64/include/uapi/asm/kvm.h | 2 ++ >> virt/kvm/arm/vgic.c | 14 +++++++++++++- >> 4 files changed, 28 insertions(+), 1 deletion(-) >> >> diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt >> index df8b0c7..80db43f 100644 >> --- a/Documentation/virtual/kvm/devices/arm-vgic.txt >> +++ b/Documentation/virtual/kvm/devices/arm-vgic.txt >> @@ -81,3 +81,14 @@ Groups: >> -EINVAL: Value set is out of the expected range >> -EBUSY: Value has already be set, or GIC has already been initialized >> with default values. >> + >> + KVM_DEV_ARM_VGIC_GRP_CTRL >> + Attributes: >> + KVM_DEV_ARM_VGIC_CTRL_INIT >> + request the initialization of the VGIC, no additional parameter in >> + kvm_device_attr.addr. >> + Errors: >> + -ENXIO: distributor or CPU interface base address were not set prior >> + to that call > > this should be more generic to also apply to GICv3, I would suggest: > > "VGIC not properly configured as required prior to calling this > attribute." corrected > > alternatively, the attribute should be KVM_DEV_ARM_VGIC_V2_CTRL_INIT. > >> + -EINVAL: number of vcpus is not known > > can we have a different error code for this case? ENODEV for example? corrected Thanks Eric > >> + -ENOMEM: memory shortage when allocating vgic internal data > >> diff --git a/arch/arm/include/uapi/asm/kvm.h b/arch/arm/include/uapi/asm/kvm.h >> index 77547bb..2499867 100644 >> --- a/arch/arm/include/uapi/asm/kvm.h >> +++ b/arch/arm/include/uapi/asm/kvm.h >> @@ -175,6 +175,8 @@ struct kvm_arch_memory_slot { >> #define KVM_DEV_ARM_VGIC_OFFSET_SHIFT 0 >> #define KVM_DEV_ARM_VGIC_OFFSET_MASK (0xffffffffULL << KVM_DEV_ARM_VGIC_OFFSET_SHIFT) >> #define KVM_DEV_ARM_VGIC_GRP_NR_IRQS 3 >> +#define KVM_DEV_ARM_VGIC_GRP_CTRL 4 >> +#define KVM_DEV_ARM_VGIC_CTRL_INIT 0 >> >> /* KVM_IRQ_LINE irq field index values */ >> #define KVM_ARM_IRQ_TYPE_SHIFT 24 >> diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h >> index 1ed4417..b35c95a 100644 >> --- a/arch/arm64/include/uapi/asm/kvm.h >> +++ b/arch/arm64/include/uapi/asm/kvm.h >> @@ -161,6 +161,8 @@ struct kvm_arch_memory_slot { >> #define KVM_DEV_ARM_VGIC_OFFSET_SHIFT 0 >> #define KVM_DEV_ARM_VGIC_OFFSET_MASK (0xffffffffULL << KVM_DEV_ARM_VGIC_OFFSET_SHIFT) >> #define KVM_DEV_ARM_VGIC_GRP_NR_IRQS 3 >> +#define KVM_DEV_ARM_VGIC_GRP_CTRL 4 >> +#define KVM_DEV_ARM_VGIC_CTRL_INIT 0 >> >> /* KVM_IRQ_LINE irq field index values */ >> #define KVM_ARM_IRQ_TYPE_SHIFT 24 >> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c >> index b76c38c..2fe5bdb 100644 >> --- a/virt/kvm/arm/vgic.c >> +++ b/virt/kvm/arm/vgic.c >> @@ -2474,7 +2474,14 @@ static int vgic_set_attr(struct kvm_device *dev, struct kvm_device_attr *attr) >> >> return ret; >> } >> - >> + case KVM_DEV_ARM_VGIC_GRP_CTRL: { >> + switch (attr->attr) { >> + case KVM_DEV_ARM_VGIC_CTRL_INIT: >> + r = kvm_vgic_init(dev->kvm); >> + return r; >> + } >> + break; >> + } >> } >> >> return -ENXIO; >> @@ -2553,6 +2560,11 @@ static int vgic_has_attr(struct kvm_device *dev, struct kvm_device_attr *attr) >> return vgic_has_attr_regs(vgic_cpu_ranges, offset); >> case KVM_DEV_ARM_VGIC_GRP_NR_IRQS: >> return 0; >> + case KVM_DEV_ARM_VGIC_GRP_CTRL: >> + switch (attr->attr) { >> + case KVM_DEV_ARM_VGIC_CTRL_INIT: >> + return 0; >> + } >> } >> return -ENXIO; >> } >> -- >> 1.9.1 >> -- 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/