From patchwork Fri Jul 15 11:37:49 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sasha Levin X-Patchwork-Id: 977962 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter1.kernel.org (8.14.4/8.14.4) with ESMTP id p6FBd69n030870 for ; Fri, 15 Jul 2011 11:39:06 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751972Ab1GOLjD (ORCPT ); Fri, 15 Jul 2011 07:39:03 -0400 Received: from mail-ww0-f44.google.com ([74.125.82.44]:46021 "EHLO mail-ww0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751953Ab1GOLjB (ORCPT ); Fri, 15 Jul 2011 07:39:01 -0400 Received: by wwe5 with SMTP id 5so1215543wwe.1 for ; Fri, 15 Jul 2011 04:39:00 -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:in-reply-to:references; bh=Xf1p/fcaFS8Lzu4OeATDcmhFNkYM5gH17780LBfwldQ=; b=SohM2AfGmC2s7cKYe/0cgTkgrbMVXgnkCASkt10tCRVZy6kSRpk0tAhpGX/SzacAZn 4GBnah6tNkadZ4ZNWzvGd3ECPU4zIk0eolGpipG4Id52UoUzrcSp5ID8QUq9t517H87f z6XxnpPnhWiahHQKEIdZvL3MNDZjD/z+PpDUU= Received: by 10.216.78.144 with SMTP id g16mr2844495wee.64.1310729939036; Fri, 15 Jul 2011 04:38:59 -0700 (PDT) Received: from localhost.localdomain (bzq-79-182-205-17.red.bezeqint.net [79.182.205.17]) by mx.google.com with ESMTPS id f1sm685589wed.38.2011.07.15.04.38.57 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 15 Jul 2011 04:38:58 -0700 (PDT) From: Sasha Levin To: kvm@vger.kernel.org Cc: Sasha Levin , Avi Kivity , Ingo Molnar , Marcelo Tosatti , Pekka Enberg Subject: [PATCH v2 2/2] x86: Raise the hard VCPU count limit Date: Fri, 15 Jul 2011 14:37:49 +0300 Message-Id: <1310729869-1451-2-git-send-email-levinsasha928@gmail.com> X-Mailer: git-send-email 1.7.6 In-Reply-To: <1310729869-1451-1-git-send-email-levinsasha928@gmail.com> References: <1310729869-1451-1-git-send-email-levinsasha928@gmail.com> 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 (demeter1.kernel.org [140.211.167.41]); Fri, 15 Jul 2011 11:39:07 +0000 (UTC) The patch raises the hard limit of VCPU count to 254. 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 254. Cc: Avi Kivity Cc: Ingo Molnar Cc: Marcelo Tosatti Cc: Pekka Enberg Suggested-by: Pekka Enberg Signed-off-by: Sasha Levin --- 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 b0e4b9c..c37022e 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. On powerpc using book3s_hv mode, the vcpus are mapped onto virtual threads in one or more virtual CPU cores. (This is because the diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index dd51c83..9256fa0 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 254 +#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 84a28ea..8360569 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2086,6 +2086,9 @@ 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 2c366b5..55f5afb 100644 --- a/include/linux/kvm.h +++ b/include/linux/kvm.h @@ -463,7 +463,7 @@ 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 @@ -553,6 +553,7 @@ struct kvm_ppc_pvinfo { #define KVM_CAP_SPAPR_TCE 63 #define KVM_CAP_PPC_SMT 64 #define KVM_CAP_PPC_RMA 65 +#define KVM_CAP_MAX_VCPUS 66 /* returns max vcpus per vm */ #ifdef KVM_CAP_IRQ_ROUTING