From patchwork Thu Mar 30 12:35:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hou Wenlong X-Patchwork-Id: 13194116 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38F6DC761A6 for ; Thu, 30 Mar 2023 12:36:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230476AbjC3MgC (ORCPT ); Thu, 30 Mar 2023 08:36:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56938 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229661AbjC3MgB (ORCPT ); Thu, 30 Mar 2023 08:36:01 -0400 Received: from out0-209.mail.aliyun.com (out0-209.mail.aliyun.com [140.205.0.209]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5F49A7681; Thu, 30 Mar 2023 05:35:59 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R961e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018047203;MF=houwenlong.hwl@antgroup.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---.S2zl1PU_1680179755; Received: from localhost(mailfrom:houwenlong.hwl@antgroup.com fp:SMTPD_---.S2zl1PU_1680179755) by smtp.aliyun-inc.com; Thu, 30 Mar 2023 20:35:55 +0800 From: "Hou Wenlong" To: kvm@vger.kernel.org Cc: Paolo Bonzini , Jonathan Corbet , Sean Christopherson , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] KVM: x86: Disallow enable KVM_CAP_X86_DISABLE_EXITS capability after vCPUs have been created Date: Thu, 30 Mar 2023 20:35:52 +0800 Message-Id: <9227068821b275ac547eb2ede09ec65d2281fe07.1680179693.git.houwenlong.hwl@antgroup.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Disable PAUSE/MWAIT/HLT exits after vCPUs have been created is useless, because PAUSE/MWAIT/HLT intercepts configuration is not changed after vCPU created. And two vCPUs may have inconsistent configuration if disable PAUSE/MWAIT/HLT exits between those two vCPUs creation. Since it's a per-VM capability, all vCPUs should keep same configuration, so disallow enable KVM_CAP_X86_DISABLE_EXITS capability after vCPUs have been created. Signed-off-by: Hou Wenlong --- Documentation/virt/kvm/api.rst | 3 ++- arch/x86/kvm/x86.c | 5 +++++ 2 files changed, 7 insertions(+), 1 deletion(-) base-commit: 27d6845d258b67f4eb3debe062b7dacc67e0c393 diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index a69e91088d76..95a683a27cf2 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -7179,7 +7179,8 @@ branch to guests' 0x200 interrupt vector. :Architectures: x86 :Parameters: args[0] defines which exits are disabled -:Returns: 0 on success, -EINVAL when args[0] contains invalid exits +:Returns: 0 on success, -EINVAL when args[0] contains invalid exits or + any vCPUs have been created. Valid bits in args[0] are:: diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2c0ff40e5345..7e97595465fc 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6275,6 +6275,9 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, if (cap->args[0] & ~KVM_X86_DISABLE_VALID_EXITS) break; + mutex_lock(&kvm->lock); + if (kvm->created_vcpus) + goto disable_exits_unlock; if (cap->args[0] & KVM_X86_DISABLE_EXITS_PAUSE) kvm->arch.pause_in_guest = true; @@ -6296,6 +6299,8 @@ int kvm_vm_ioctl_enable_cap(struct kvm *kvm, } r = 0; +disable_exits_unlock: + mutex_unlock(&kvm->lock); break; case KVM_CAP_MSR_PLATFORM_INFO: kvm->arch.guest_can_read_msr_platform_info = cap->args[0];