From patchwork Sat Jul 9 12:25:20 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 959452 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter2.kernel.org (8.14.4/8.14.4) with ESMTP id p69CPgNH022102 for ; Sat, 9 Jul 2011 12:25:42 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751491Ab1GIMZk (ORCPT ); Sat, 9 Jul 2011 08:25:40 -0400 Received: from mail-wy0-f174.google.com ([74.125.82.174]:59024 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751447Ab1GIMZk (ORCPT ); Sat, 9 Jul 2011 08:25:40 -0400 Received: by wyg8 with SMTP id 8so1786685wyg.19 for ; Sat, 09 Jul 2011 05:25:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer; bh=QGLiDOQoSNNkAIPP06DFdZqvtYF+w5/UJRchxrb3D5k=; b=b0QXvdkWJg3r/2cg2v2I3AYNgbrxYl63kWutPGibkWZjn/lCB3zGT4BicVTROguM3b HV88LutJWYaUVpqNHrqz6gOqOqq6R3CqYcVzubZ0IkLWv2Pl2gHZirWjeWNAjPMrKHYA RKIEkVHkd+8CpK4OLu0w6ZwGTxB5DivUV0U60= Received: by 10.216.62.204 with SMTP id y54mr2508756wec.73.1310214338559; Sat, 09 Jul 2011 05:25:38 -0700 (PDT) Received: from localhost.localdomain (bzq-79-178-209-230.red.bezeqint.net [79.178.209.230]) by mx.google.com with ESMTPS id n21sm5862733wed.43.2011.07.09.05.25.36 (version=TLSv1/SSLv3 cipher=OTHER); Sat, 09 Jul 2011 05:25:38 -0700 (PDT) From: Sasha Levin To: kvm@vger.kernel.org Cc: Sasha Levin , Avi Kivity , Ingo Molnar , Marcelo Tosatti , Pekka Enberg Subject: [PATCH] x86: Raise the hard VCPU count limit Date: Sat, 9 Jul 2011 15:25:20 +0300 Message-Id: <1310214320-12488-1-git-send-email-levinsasha928@gmail.com> X-Mailer: git-send-email 1.7.6 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.6 (demeter2.kernel.org [140.211.167.43]); Sat, 09 Jul 2011 12:25:43 +0000 (UTC) The patch raises the hard limit of VCPU count to 1024. This will allow developers to easily work on scalability and will allow users to test high VCPU setups easily without patching the kernel. To prevent possible issues with current setups, KVM_CAP_NR_VCPUS now returns the recommended VCPU limit (which is still 64) - this should be a safe value for everybody, while a new KVM_CAP_MAX_VCPUS returns the hard limit which is now 1024. Cc: Avi Kivity Cc: Ingo Molnar Cc: Marcelo Tosatti Cc: Pekka Enberg Suggested-by: Pekka Enberg Signed-off-by: Sasha Levin Acked-by: Pekka Enbeg --- Documentation/virtual/kvm/api.txt | 11 +++++++++-- arch/x86/include/asm/kvm_host.h | 3 ++- arch/x86/kvm/x86.c | 3 +++ include/linux/kvm.h | 3 ++- 4 files changed, 16 insertions(+), 4 deletions(-) diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt index 42542eb..84883a0 100644 --- a/Documentation/virtual/kvm/api.txt +++ b/Documentation/virtual/kvm/api.txt @@ -175,10 +175,17 @@ Parameters: vcpu id (apic id on x86) Returns: vcpu fd on success, -1 on error This API adds a vcpu to a virtual machine. The vcpu id is a small integer -in the range [0, max_vcpus). You can use KVM_CAP_NR_VCPUS of the -KVM_CHECK_EXTENSION ioctl() to determine the value for max_vcpus at run-time. +in the range [0, max_vcpus). + +The recommended max_vcpus value can be retrieved using the KVM_CAP_NR_VCPUS of +the KVM_CHECK_EXTENSION ioctl() at run-time. +The maximum possible value for max_vcpus can be retrieved using the +KVM_CAP_MAX_VCPUS of the KVM_CHECK_EXTENSION ioctl() at run-time. + If the KVM_CAP_NR_VCPUS does not exist, you should assume that max_vcpus is 4 cpus max. +If the KVM_CAP_MAX_VCPUS does not exist, you should assume that max_vcpus is +same as the value returned from KVM_CAP_NR_VCPUS. 4.8 KVM_GET_DIRTY_LOG (vm ioctl) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index d2ac8e2..7db3e66 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -26,7 +26,8 @@ #include #include -#define KVM_MAX_VCPUS 64 +#define KVM_MAX_VCPUS 1024 +#define KVM_SOFT_MAX_VCPUS 64 #define KVM_MEMORY_SLOTS 32 /* memory slots that does not exposed to userspace */ #define KVM_PRIVATE_MEM_SLOTS 4 diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 77c9d86..9766f46 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2006,6 +2006,9 @@ int kvm_dev_ioctl_check_extension(long ext) r = !kvm_x86_ops->cpu_has_accelerated_tpr(); break; case KVM_CAP_NR_VCPUS: + r = KVM_SOFT_MAX_VCPUS; + break; + case KVM_CAP_MAX_VCPUS: r = KVM_MAX_VCPUS; break; case KVM_CAP_NR_MEMSLOTS: diff --git a/include/linux/kvm.h b/include/linux/kvm.h index 55ef181..077c193 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -457,7 +457,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_VAPIC 6 #define KVM_CAP_EXT_CPUID 7 #define KVM_CAP_CLOCKSOURCE 8 -#define KVM_CAP_NR_VCPUS 9 /* returns max vcpus per vm */ +#define KVM_CAP_NR_VCPUS 9 /* returns recommended max vcpus per vm */ #define KVM_CAP_NR_MEMSLOTS 10 /* returns max memory slots per vm */ #define KVM_CAP_PIT 11 #define KVM_CAP_NOP_IO_DELAY 12 @@ -544,6 +544,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_TSC_CONTROL 60 #define KVM_CAP_GET_TSC_KHZ 61 #define KVM_CAP_PPC_BOOKE_SREGS 62 +#define KVM_CAP_MAX_VCPUS 63 /* returns max vcpus per vm */ #ifdef KVM_CAP_IRQ_ROUTING