From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752220Ab2LJRcz (ORCPT ); Mon, 10 Dec 2012 12:32:55 -0500 Received: from mx1.redhat.com ([209.132.183.28]:20047 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752007Ab2LJRcw (ORCPT ); Mon, 10 Dec 2012 12:32:52 -0500 Subject: [PATCH v2 02/10] kvm: Check userspace_addr when modifying a memory slot To: mtosatti@redhat.com, gleb@redhat.com From: Alex Williamson Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org Date: Mon, 10 Dec 2012 10:32:51 -0700 Message-ID: <20121210173251.10461.58971.stgit@bling.home> In-Reply-To: <20121210171417.10461.20079.stgit@bling.home> References: <20121210171417.10461.20079.stgit@bling.home> User-Agent: StGit/0.16 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The API documents that only flags and guest physical memory space can be modified on an existing slot, but we don't enforce that the userspace address cannot be modified. Instead we just ignore it. This means that a user may think they've successfully moved both the guest and user addresses, when in fact only the guest address changed. Check and error instead. Signed-off-by: Alex Williamson --- virt/kvm/kvm_main.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e426704..6e9d3f9 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -779,13 +779,19 @@ int __kvm_set_memory_region(struct kvm *kvm, r = -ENOMEM; - /* Allocate if a slot is being created */ + /* + * Allocate if a slot is being created. If modifying a slot, + * the userspace_addr cannot change. + */ if (!old.npages) { new.user_alloc = user_alloc; new.userspace_addr = mem->userspace_addr; if (kvm_arch_create_memslot(&new, npages)) goto out_free; + } else if (npages && mem->userspace_addr != old.userspace_addr) { + r = -EINVAL; + goto out_free; } /* Allocate page dirty bitmap if needed */