From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mats Petersson Subject: Re: CR3 Virtual Address Date: Wed, 28 Nov 2012 15:06:00 +0000 Message-ID: <50B62858.8040302@citrix.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: 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 List-Id: xen-devel@lists.xenproject.org On 28/11/12 14:48, emdel wrote: > Hello everybody, > > I have to work with the Xen 4.2 memory management code for a research > project and I have some questions. > > 1) Since I have to change and/or remove some entries in the hypervisor > page table, I would like to know the "virtual address" of the CR3 > register. As per Andy Cooper's answer, but further: Exactly (or at least roughly) what are you trying to achieve? You want to "remove" some memory from the hypervisor itself? Who/what will use this memory? It is MUCH easier to advice on HOW to do something if we understand what you are actually trying to do. > > 2) I would also like to know if the VMCS virtual address is mapped > inside the > page table pointed by the HOST_CR3. The "HOST_CR3" is the Xen (VCPU's) true CR3 (for the "host" or "root" mode, as Intel calls it - this is the hypervisor itself). it is set from vcpu.arch.cr3. So the VMCS is available here, or the system would crash when it returns from guest operation. > > 3) Are there functions to perform the page walking on the hypervisor > page tables? Yes. As per Andy Cooper's answer. -- Mats > > > Thank you for the attention, > > > Best Regards.