From nobody Wed Nov 12 01:52:17 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1566922219; cv=none; d=zoho.com; s=zohoarc; b=CHltTl2mZ3pqk9kVcO15nr7J0ZvwbvakW01Z/xgk7m6XV5B2S+IyQQqpsP+geTmlOymSR7fjXDyP/765DVURfFILzb9cerS/M4EVrefLkPLQAOCJw/4SD5dqQABAblqtHn4E7ZJOn2s61gf4B1Dd4r/KBXFVKUaLk+aslaUwDBk= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zoho.com; s=zohoarc; t=1566922219; h=Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To:ARC-Authentication-Results; bh=gxOv0epSFSPjU2WGBpdNnv2b4bYsO5u9ZL4Ti0AQEKA=; b=OXkSjxydC9gWnOt5bH6S8rhfBHQ9r+LT3eHsdUgP0SVjWC3B/72TGlCulcBemadfODG1N0xYAfLKrzR+Eobc5uk6TEugLbZ5KVrZRo8FcfbHhJ7nSLlsYo+9i1oCtK05STk79ynh/QKckpJuLTypMgiszTKndqQQ0vEC3noQ+hE= ARC-Authentication-Results: i=1; mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 15669222192821000.7172110222949; Tue, 27 Aug 2019 09:10:19 -0700 (PDT) Received: from localhost ([::1]:53692 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i2e2z-0007TO-L4 for importer@patchew.org; Tue, 27 Aug 2019 12:10:17 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58517) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i2dz6-0003IR-Gn for qemu-devel@nongnu.org; Tue, 27 Aug 2019 12:06:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i2dz5-0002FA-5u for qemu-devel@nongnu.org; Tue, 27 Aug 2019 12:06:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:49142) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i2dz1-0002Du-Gs; Tue, 27 Aug 2019 12:06:11 -0400 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C8AA67FDFB; Tue, 27 Aug 2019 16:06:10 +0000 (UTC) Received: from laptop.redhat.com (ovpn-116-105.ams2.redhat.com [10.36.116.105]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9DCBD1001B13; Tue, 27 Aug 2019 16:06:07 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, peter.maydell@linaro.org Date: Tue, 27 Aug 2019 18:05:54 +0200 Message-Id: <20190827160554.30995-4-eric.auger@redhat.com> In-Reply-To: <20190827160554.30995-1-eric.auger@redhat.com> References: <20190827160554.30995-1-eric.auger@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Tue, 27 Aug 2019 16:06:10 +0000 (UTC) Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [RFC 3/3] virt: Check KVM_CAP_ARM_IRQ_LINE_LAYOUT_2 for smp_cpus > 256 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: yuzenghui@huawei.com, maz@kernel.org Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Type: text/plain; charset="utf-8" Host kernel within [4.18, 5.3] report an erroneous KVM_MAX_VCPUS=3D512 for ARM. The actual capability to instantiate more than 256 vcpus was fixed in 5.4 with the upgrade of the KVM_IRQ_LINE ABI to support vcpu id encoded on 12 bits instead of 8 and a redistributor consuming a single KVM IO device instead of 2. So let's check this capability when attempting to use more than 256 vcpus. Signed-off-by: Eric Auger --- hw/arm/virt.c | 7 +++++++ target/arm/kvm.c | 7 +++++++ target/arm/kvm_arm.h | 13 +++++++++++++ 3 files changed, 27 insertions(+) diff --git a/hw/arm/virt.c b/hw/arm/virt.c index 0d1629ccb3..bcc8d64384 100644 --- a/hw/arm/virt.c +++ b/hw/arm/virt.c @@ -1575,6 +1575,13 @@ static void machvirt_init(MachineState *machine) virt_max_cpus =3D GIC_NCPU; } =20 + if (kvm_enabled() && max_cpus > 256 && + !kvm_arm_irq_line_layout_2(MACHINE(vms))) { + error_report("Using more than 256 vcpus require a host kernel " + "with KVM_CAP_ARM_IRQ_LINE_LAYOUT_2"); + exit(1); + } + if (max_cpus > virt_max_cpus) { error_report("Number of SMP CPUs requested (%d) exceeds max CPUs " "supported by machine 'mach-virt' (%d)", diff --git a/target/arm/kvm.c b/target/arm/kvm.c index b2eaa50b8d..db88fcc5bf 100644 --- a/target/arm/kvm.c +++ b/target/arm/kvm.c @@ -171,6 +171,13 @@ bool kvm_arm_pmu_supported(CPUState *cpu) return kvm_check_extension(s, KVM_CAP_ARM_PMU_V3); } =20 +bool kvm_arm_irq_line_layout_2(MachineState *ms) +{ + KVMState *s =3D KVM_STATE(ms->accelerator); + + return kvm_check_extension(s, KVM_CAP_ARM_IRQ_LINE_LAYOUT_2); +} + int kvm_arm_get_max_vm_ipa_size(MachineState *ms) { KVMState *s =3D KVM_STATE(ms->accelerator); diff --git a/target/arm/kvm_arm.h b/target/arm/kvm_arm.h index b3106c8600..06b4db4513 100644 --- a/target/arm/kvm_arm.h +++ b/target/arm/kvm_arm.h @@ -233,6 +233,14 @@ bool kvm_arm_pmu_supported(CPUState *cs); */ int kvm_arm_get_max_vm_ipa_size(MachineState *ms); =20 +/** + * kvm_arm_irq_line_layout_2 - Returns whether more than 256 + * vcpus are supported by KVM_IRQ_LINE + * + * @ms: Machine state handle + */ +bool kvm_arm_irq_line_layout_2(MachineState *ms); + /** * kvm_arm_sync_mpstate_to_kvm * @cpu: ARMCPU @@ -280,6 +288,11 @@ static inline int kvm_arm_get_max_vm_ipa_size(MachineS= tate *ms) return -ENOENT; } =20 +static inline int kvm_arm_irq_line_layout_2(MachineState *ms) +{ + return -ENOENT; +} + static inline int kvm_arm_vgic_probe(void) { return 0; --=20 2.20.1