From patchwork Mon Apr 27 14:17:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marc Zyngier X-Patchwork-Id: 11512315 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6050392A for ; Mon, 27 Apr 2020 14:17:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 44329206D4 for ; Mon, 27 Apr 2020 14:17:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587997072; bh=CSSnDMC5PzLW9Ty/t6vNkRAXv5DRYOcczqebb1dCB8w=; h=From:To:Cc:Subject:Date:List-ID:From; b=i7Z7E6ZtrUyHJSYVekxy2AZCfXB61Azqf4OnZuip3OFZdyBsq/iavXw/kg6unn4DV 5m+ZCFHECNM4LEG71LRsu0uwZX1YAFbQihqNP/U8tzcP51uy/WYCDdNNN/Yi546hpD ps1VuXWbEDjX/Ahpu/iIq1ea1sm49fr/jxh/XL+k= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727943AbgD0ORv (ORCPT ); Mon, 27 Apr 2020 10:17:51 -0400 Received: from mail.kernel.org ([198.145.29.99]:44442 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726651AbgD0ORv (ORCPT ); Mon, 27 Apr 2020 10:17:51 -0400 Received: from disco-boy.misterjones.org (disco-boy.misterjones.org [51.254.78.96]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 63460206B6; Mon, 27 Apr 2020 14:17:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587997070; bh=CSSnDMC5PzLW9Ty/t6vNkRAXv5DRYOcczqebb1dCB8w=; h=From:To:Cc:Subject:Date:From; b=pzItXPTziBM5cfmNXO7kDO4LK36WFULj6A7TjQQnL4oRHAcho6MAGywU/VzBc2dPh 4FQeR5lP2RXyYOKWneuAeGRzQaBrFaATmt9Eun8Qbn6OX0fADcX3ZpLeJbi9UEMRNu 70GmJmp62lCh+0GfHqpNab9UNF1d11/vl78T4whA= Received: from 78.163-31-62.static.virginmediabusiness.co.uk ([62.31.163.78] helo=why.lan) by disco-boy.misterjones.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jT4Zw-006kdf-Qq; Mon, 27 Apr 2020 15:17:48 +0100 From: Marc Zyngier To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org Cc: James Morse , Julien Thierry , Suzuki K Poulose , Will Deacon , Andre Przywara , Ard Biesheuvel Subject: [PATCH][kvmtool] kvm: Request VM specific limits instead of system-wide ones Date: Mon, 27 Apr 2020 15:17:38 +0100 Message-Id: <20200427141738.285217-1-maz@kernel.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 62.31.163.78 X-SA-Exim-Rcpt-To: kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org, james.morse@arm.com, julien.thierry.kdev@gmail.com, suzuki.poulose@arm.com, will@kernel.org, Andre.Przywara@arm.com, ardb@kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On arm64, the maximum number of vcpus is constrained by the type of interrupt controller that has been selected (GICv2 imposes a limit of 8 vcpus, while GICv3 currently has a limit of 512). It is thus important to request this limit on the VM file descriptor rather than on the one that corresponds to /dev/kvm, as the latter is likely to return something that doesn't take the constraints into account. Reported-by: Ard Biesheuvel Signed-off-by: Marc Zyngier --- kvm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kvm.c b/kvm.c index e327541..3d5173d 100644 --- a/kvm.c +++ b/kvm.c @@ -406,7 +406,7 @@ int kvm__recommended_cpus(struct kvm *kvm) { int ret; - ret = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, KVM_CAP_NR_VCPUS); + ret = ioctl(kvm->vm_fd, KVM_CHECK_EXTENSION, KVM_CAP_NR_VCPUS); if (ret <= 0) /* * api.txt states that if KVM_CAP_NR_VCPUS does not exist, @@ -421,7 +421,7 @@ int kvm__max_cpus(struct kvm *kvm) { int ret; - ret = ioctl(kvm->sys_fd, KVM_CHECK_EXTENSION, KVM_CAP_MAX_VCPUS); + ret = ioctl(kvm->vm_fd, KVM_CHECK_EXTENSION, KVM_CAP_MAX_VCPUS); if (ret <= 0) ret = kvm__recommended_cpus(kvm);