From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?UTF-8?Q?Roger_Pau_Monn=c3=a9?= Subject: Re: [PATCH 4/5] x86/PV: remove the emulated PIT Date: Thu, 14 Jan 2016 09:25:58 +0100 Message-ID: <56975B96.8050607@citrix.com> References: <1452688338-70075-1-git-send-email-roger.pau@citrix.com> <1452688338-70075-5-git-send-email-roger.pau@citrix.com> <56968B1802000078000C66BC@prv-mh.provo.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aJdEt-0003d4-3d for xen-devel@lists.xenproject.org; Thu, 14 Jan 2016 08:26:39 +0000 In-Reply-To: <56968B1802000078000C66BC@prv-mh.provo.novell.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: Jan Beulich Cc: Andrew Cooper , xen-devel@lists.xenproject.org List-Id: xen-devel@lists.xenproject.org El 13/01/16 a les 17.36, Jan Beulich ha escrit: >>>> On 13.01.16 at 13:32, wrote: >> The HVMlite series removed the initialization of the emulated PIT for PV >> guests, but the handler was still reachable, which means a PV guests can >> crash Xen if it pokes at IO ports 0x42, 0x43 or 0x61. Completely remove the >> PV PIT handler and move the PIT initialization to HVM guests only. > > As said on IRC - this is needed for Dom0 to be able to drive the > PC speaker. You'll need to provide a fix for the suppressed > initialization instead, at least for Dom0. (As an aside, your patch > orphans hwdom_pit_access().) Thanks for the clarification. AFAICT I can leave the usage of hwdom_pit_access for Dom0, and completely remove PIT access for DomU, is that right? Roger.