From patchwork Mon Apr 27 20:06:24 2009 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marcelo Tosatti X-Patchwork-Id: 20236 Received: from vger.kernel.org (vger.kernel.org [209.132.176.167]) by demeter.kernel.org (8.14.2/8.14.2) with ESMTP id n3RK9v9C023730 for ; Mon, 27 Apr 2009 20:09:57 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758451AbZD0UJv (ORCPT ); Mon, 27 Apr 2009 16:09:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758380AbZD0UJu (ORCPT ); Mon, 27 Apr 2009 16:09:50 -0400 Received: from mx2.redhat.com ([66.187.237.31]:59314 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757168AbZD0UJr (ORCPT ); Mon, 27 Apr 2009 16:09:47 -0400 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n3RK9mUM018575 for ; Mon, 27 Apr 2009 16:09:48 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n3RK9ldM001965; Mon, 27 Apr 2009 16:09:47 -0400 Received: from amt.cnet (vpn-10-96.str.redhat.com [10.32.10.96]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n3RK9i6M010705; Mon, 27 Apr 2009 16:09:45 -0400 Received: from amt.cnet (amt.cnet [127.0.0.1]) by amt.cnet (Postfix) with ESMTP id E60C8274EDE; Mon, 27 Apr 2009 17:09:17 -0300 (BRT) Received: (from marcelo@localhost) by amt.cnet (8.14.3/8.14.3/Submit) id n3RK9Fho009112; Mon, 27 Apr 2009 17:09:15 -0300 Message-Id: <20090427200757.092796919@amt.cnet> User-Agent: quilt/0.47-1 Date: Mon, 27 Apr 2009 17:06:24 -0300 From: mtosatti@redhat.com To: kvm@vger.kernel.org Cc: Marcelo Tosatti Subject: [patch 4/4] KVM: x86: disallow changing a slots size References: <20090427200620.389589459@amt.cnet> Content-Disposition: inline; filename=disallow-alias-size-change X-Scanned-By: MIMEDefang 2.58 on 172.16.27.26 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Support to shrinking aliases complicates kernel code unnecessarily, while userspace can do the same with two operations, delete an alias, and create a new alias. Signed-off-by: Marcelo Tosatti --- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Index: kvm/arch/x86/kvm/x86.c =================================================================== --- kvm.orig/arch/x86/kvm/x86.c +++ kvm/arch/x86/kvm/x86.c @@ -1707,6 +1707,7 @@ static int kvm_vm_ioctl_set_memory_alias { int r, n; struct kvm_mem_alias *p; + unsigned long npages; r = -EINVAL; /* General sanity checks */ @@ -1728,9 +1729,12 @@ static int kvm_vm_ioctl_set_memory_alias p = &kvm->arch.aliases[alias->slot]; - /* FIXME: either disallow shrinking alias slots or disable - * size changes as done with memslots - */ + /* Disallow changing an alias slot's size. */ + npages = alias->memory_size >> PAGE_SHIFT; + r = -EINVAL; + if (npages && p->npages && npages != p->npages) + goto out_unlock; + if (!alias->memory_size) { r = -EBUSY; if (kvm_root_gfn_in_range(kvm, p->base_gfn,