From patchwork Tue Jul 31 11:18:17 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: riegamaths@gmail.com X-Patchwork-Id: 1259101 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id D196C3FC71 for ; Tue, 31 Jul 2012 11:20:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755950Ab2GaLUY (ORCPT ); Tue, 31 Jul 2012 07:20:24 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:50834 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755715Ab2GaLUX (ORCPT ); Tue, 31 Jul 2012 07:20:23 -0400 Received: by pbbrp8 with SMTP id rp8so11516633pbb.19 for ; Tue, 31 Jul 2012 04:20:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer; bh=lT6Upatyy1WoZrSpChsYfMjNxbX6N7SwwaAcUlSsnHc=; b=r8IGIFBvLcR0rh5cp8s+G/z1DMXCN4KfxE8dYGeNoPNHkzBE9jHqF5z/lvuLDBNRSz JvfgfflCucm4QFkrVcUEO8kh6ffZN/0ziCYnNQKtFY8jSWFXsizR3TmM6mR9tGgkipKa ZKR3Pd8EytKDsinaDZfhCnpU7vgLXGY5E8QtNBcJRkMaZ+idm2FnvH/IUBCAptHRR1vr beWgJ45+luI3hgcHTpsuEEv23io+cfoEMcDrf1zS9jqHH1GLhSVlvmLzD+ohQaEGATw4 QDsAWYRCrd9TtVxUsVR5Uk6ftWKJnQdcCGVniSPxqoohUo/WbfxVEPm5flU1n3YlrU9j /4tA== Received: by 10.68.132.165 with SMTP id ov5mr26536356pbb.25.1343733623157; Tue, 31 Jul 2012 04:20:23 -0700 (PDT) Received: from localhost.localdomain ([114.249.88.183]) by mx.google.com with ESMTPS id pj10sm98139pbb.46.2012.07.31.04.18.46 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 31 Jul 2012 04:20:22 -0700 (PDT) From: riegamaths@gmail.com To: qemu-devel Cc: Stefan Hajnoczi , Avi Kivity , Marcelo Tosatti , , Peter Maydell , Dunrong Huang Subject: [PATCH v3] kvm: Check if smp_cpus exceeds max cpus supported by kvm Date: Tue, 31 Jul 2012 19:18:17 +0800 Message-Id: <1343733497-26977-1-git-send-email-riegamaths@gmail.com> X-Mailer: git-send-email 1.7.8.6 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Dunrong Huang Add a helper function for fetching max cpus supported by kvm. Make QEMU exit with an error message if smp_cpus exceeds limit of VCPU count retrieved by invoking this helper function. Signed-off-by: Dunrong Huang Reviewed-by: Peter Maydell --- v1 -> v2: * Fix indentation(thanks to Stefan Hajnoczi for his review) v2 -> v3(Thanks to Peter Maydell for this hint) * Add a comment for helper function * Use "goto err" instead of "exit(1)" kvm-all.c | 29 +++++++++++++++++++++++++++++ 1 files changed, 29 insertions(+), 0 deletions(-) diff --git a/kvm-all.c b/kvm-all.c index 2148b20..bf64761 100644 --- a/kvm-all.c +++ b/kvm-all.c @@ -1207,6 +1207,26 @@ static int kvm_irqchip_create(KVMState *s) return 0; } +static int kvm_max_vcpus(KVMState *s) +{ + int ret; + + /* Find number of supported CPUs using the recommended + * procedure from the kernel API documentation to cope with + * older kernels that may be missing capabilities. + */ + ret = kvm_check_extension(s, KVM_CAP_MAX_VCPUS); + if (ret) { + return ret; + } + ret = kvm_check_extension(s, KVM_CAP_NR_VCPUS); + if (ret) { + return ret; + } + + return 4; +} + int kvm_init(void) { static const char upgrade_note[] = @@ -1216,6 +1236,7 @@ int kvm_init(void) const KVMCapabilityInfo *missing_cap; int ret; int i; + int max_vcpus; s = g_malloc0(sizeof(KVMState)); @@ -1256,6 +1277,14 @@ int kvm_init(void) goto err; } + max_vcpus = kvm_max_vcpus(s); + if (smp_cpus > max_vcpus) { + ret = -EINVAL; + fprintf(stderr, "Number of SMP cpus requested (%d) exceeds max cpus " + "supported by KVM (%d)\n", smp_cpus, max_vcpus); + goto err; + } + s->vmfd = kvm_ioctl(s, KVM_CREATE_VM, 0); if (s->vmfd < 0) { #ifdef TARGET_S390X