From mboxrd@z Thu Jan 1 00:00:00 1970 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 06593C6FD1D for ; Wed, 15 Mar 2023 12:33:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232636AbjCOMdG (ORCPT ); Wed, 15 Mar 2023 08:33:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232649AbjCOMcw (ORCPT ); Wed, 15 Mar 2023 08:32:52 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DA2F28EA32 for ; Wed, 15 Mar 2023 05:31:58 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3D7AE613F9 for ; Wed, 15 Mar 2023 12:31:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 54192C433D2; Wed, 15 Mar 2023 12:31:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1678883517; bh=zMJcQZY4dDA3lZHLSJyw1spa8aO4z8+bLFmPEKMNJG8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=zVFIXAgR+1c4CXOpNbzHtIDiL76x0RE0FnUg9yqsBrSCLugdMfW1og2wEc2z92Jmk JE66MXGJI7svKLWpu05Mb5uKsf5wgbkihdy78VFBJnEPM9uxqczyzIfMGve+PyMcAL 6t1SNbMUPVMR6bNYhnkyaKyl0MpkwN9jJIwQtUE4= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sean Christopherson , Paolo Bonzini , Sasha Levin Subject: [PATCH 6.1 029/143] KVM: VMX: Do _all_ initialization before exposing /dev/kvm to userspace Date: Wed, 15 Mar 2023 13:11:55 +0100 Message-Id: <20230315115741.394876122@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230315115740.429574234@linuxfoundation.org> References: <20230315115740.429574234@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Sean Christopherson [ Upstream commit e32b120071ea114efc0b4ddd439547750b85f618 ] Call kvm_init() only after _all_ setup is complete, as kvm_init() exposes /dev/kvm to userspace and thus allows userspace to create VMs (and call other ioctls). E.g. KVM will encounter a NULL pointer when attempting to add a vCPU to the per-CPU loaded_vmcss_on_cpu list if userspace is able to create a VM before vmx_init() configures said list. BUG: kernel NULL pointer dereference, address: 0000000000000008 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page PGD 0 P4D 0 Oops: 0002 [#1] SMP CPU: 6 PID: 1143 Comm: stable Not tainted 6.0.0-rc7+ #988 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:vmx_vcpu_load_vmcs+0x68/0x230 [kvm_intel] vmx_vcpu_load+0x16/0x60 [kvm_intel] kvm_arch_vcpu_load+0x32/0x1f0 [kvm] vcpu_load+0x2f/0x40 [kvm] kvm_arch_vcpu_create+0x231/0x310 [kvm] kvm_vm_ioctl+0x79f/0xe10 [kvm] ? handle_mm_fault+0xb1/0x220 __x64_sys_ioctl+0x80/0xb0 do_syscall_64+0x2b/0x50 entry_SYSCALL_64_after_hwframe+0x46/0xb0 RIP: 0033:0x7f5a6b05743b Modules linked in: vhost_net vhost vhost_iotlb tap kvm_intel(+) kvm irqbypass Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Message-Id: <20221130230934.1014142-15-seanjc@google.com> Signed-off-by: Paolo Bonzini Signed-off-by: Sasha Levin --- arch/x86/kvm/vmx/vmx.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 81a23ae4f872b..bc868958e91fe 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -8456,19 +8456,23 @@ static void vmx_cleanup_l1d_flush(void) l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_AUTO; } -static void vmx_exit(void) +static void __vmx_exit(void) { + allow_smaller_maxphyaddr = false; + #ifdef CONFIG_KEXEC_CORE RCU_INIT_POINTER(crash_vmclear_loaded_vmcss, NULL); synchronize_rcu(); #endif + vmx_cleanup_l1d_flush(); +} +static void vmx_exit(void) +{ kvm_exit(); kvm_x86_vendor_exit(); - vmx_cleanup_l1d_flush(); - - allow_smaller_maxphyaddr = false; + __vmx_exit(); } module_exit(vmx_exit); @@ -8513,11 +8517,6 @@ static int __init vmx_init(void) if (r) return r; - r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx), - __alignof__(struct vcpu_vmx), THIS_MODULE); - if (r) - goto err_kvm_init; - /* * Must be called after common x86 init so enable_ept is properly set * up. Hand the parameter mitigation value in which was stored in @@ -8551,11 +8550,20 @@ static int __init vmx_init(void) if (!enable_ept) allow_smaller_maxphyaddr = true; + /* + * Common KVM initialization _must_ come last, after this, /dev/kvm is + * exposed to userspace! + */ + r = kvm_init(&vmx_init_ops, sizeof(struct vcpu_vmx), + __alignof__(struct vcpu_vmx), THIS_MODULE); + if (r) + goto err_kvm_init; + return 0; -err_l1d_flush: - vmx_exit(); err_kvm_init: + __vmx_exit(); +err_l1d_flush: kvm_x86_vendor_exit(); return r; } -- 2.39.2