From mboxrd@z Thu Jan 1 00:00:00 1970 From: George Dunlap Subject: [PATCH RFC v12 09/21] pvh: Do not allow PVH guests to change paging modes Date: Fri, 13 Sep 2013 17:25:09 +0100 Message-ID: <1379089521-25720-10-git-send-email-george.dunlap@eu.citrix.com> References: <1379089521-25720-1-git-send-email-george.dunlap@eu.citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1379089521-25720-1-git-send-email-george.dunlap@eu.citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xen.org Cc: George Dunlap , Keir Fraser , Tim Deegan , Jan Beulich List-Id: xen-devel@lists.xenproject.org Signed-off-by: George Dunlap Signed-off-by: Mukesh Rathor CC: Jan Beulich CC: Tim Deegan CC: Keir Fraser --- xen/arch/x86/hvm/hvm.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c index 6a7a006..b59ff52 100644 --- a/xen/arch/x86/hvm/hvm.c +++ b/xen/arch/x86/hvm/hvm.c @@ -1743,7 +1743,17 @@ int hvm_set_cr0(unsigned long value) (value & (X86_CR0_PE | X86_CR0_PG)) == X86_CR0_PG ) goto gpf; - if ( (value & X86_CR0_PG) && !(old_value & X86_CR0_PG) ) + + + /* A pvh is not expected to change to real mode. */ + if ( is_pvh_vcpu(v) + && (value & (X86_CR0_PE | X86_CR0_PG)) != (X86_CR0_PG | X86_CR0_PE) ) + { + printk(XENLOG_G_WARNING + "PVH attempting to turn off PE/PG. CR0:%lx\n", value); + goto gpf; + } + else if ( (value & X86_CR0_PG) && !(old_value & X86_CR0_PG) ) { if ( v->arch.hvm_vcpu.guest_efer & EFER_LME ) { -- 1.7.9.5