From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932792Ab0IXQ2s (ORCPT ); Fri, 24 Sep 2010 12:28:48 -0400 Received: from kroah.org ([198.145.64.141]:38484 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932744Ab0IXQ2p (ORCPT ); Fri, 24 Sep 2010 12:28:45 -0400 X-Mailbox-Line: From gregkh@clark.site Fri Sep 24 09:26:20 2010 Message-Id: <20100924162620.022536179@clark.site> User-Agent: quilt/0.48-11.2 Date: Fri, 24 Sep 2010 09:24:47 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, greg@kroah.com Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, avi@redhat.com, mtosatti@redhat.com Subject: [59/80] KVM: VMX: Fix host GDT.LIMIT corruption In-Reply-To: <20100924162706.GA7381@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.35-stable review patch. If anyone has any objections, please let us know. ------------------ From: Avi Kivity commit 3444d7da1839b851eefedd372978d8a982316c36 upstream. vmx does not restore GDT.LIMIT to the host value, instead it sets it to 64KB. This means host userspace can learn a few bits of host memory. Fix by reloading GDTR when we load other host state. Signed-off-by: Avi Kivity Signed-off-by: Marcelo Tosatti Signed-off-by: Greg Kroah-Hartman --- arch/x86/kvm/vmx.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -177,6 +177,7 @@ static u64 construct_eptp(unsigned long static DEFINE_PER_CPU(struct vmcs *, vmxarea); static DEFINE_PER_CPU(struct vmcs *, current_vmcs); static DEFINE_PER_CPU(struct list_head, vcpus_on_cpu); +static DEFINE_PER_CPU(struct desc_ptr, host_gdt); static unsigned long *vmx_io_bitmap_a; static unsigned long *vmx_io_bitmap_b; @@ -812,6 +813,7 @@ static void __vmx_load_host_state(struct wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base); } #endif + load_gdt(&__get_cpu_var(host_gdt)); } static void vmx_load_host_state(struct vcpu_vmx *vmx) @@ -1314,6 +1316,8 @@ static int hardware_enable(void *garbage ept_sync_global(); + store_gdt(&__get_cpu_var(host_gdt)); + return 0; }