From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Dont leak debug flugs in ioctl_get_regs()? Date: Sun, 22 Jul 2007 13:32:25 +0300 Message-ID: <46A33239.8010709@qumranet.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: Jun Koi Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Jun Koi wrote: > Hi, > > In kvm_vcpu_ioctl_get_regs() function (kvm_main.c), we have a comment > like this: "Dont leak debug flags in case they were set for guest > debugging". > > What is the reasons that make us filter out TF and RF bit in EFLAGS like that? > VT and SVM don't virtualize the debug flags. So when we debug the guest, we modify the guest's TF and RF, not some hardware-provided shadow register. So, when we look at the guest's eflags, we need to consider that some of the bits are owned by the host, not the guest. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/