From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [PATCH 5/5] x86/HVM: don't setup an intercept handler for IO port 0xcf8 unconditionally Date: Thu, 14 Jan 2016 02:12:41 -0700 Message-ID: <5697749902000078000C6998@prv-mh.provo.novell.com> References: <1452688338-70075-1-git-send-email-roger.pau@citrix.com> <1452688338-70075-6-git-send-email-roger.pau@citrix.com> <56968BA902000078000C66BF@prv-mh.provo.novell.com> <8122e183a2d14f759d983acf2777be06@AMSPEX02CL03.citrite.net> <56975DC7.3070905@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1aJdxU-0005tD-R0 for xen-devel@lists.xenproject.org; Thu, 14 Jan 2016 09:12:44 +0000 In-Reply-To: <56975DC7.3070905@citrix.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: =?UTF-8?Q?Roger=20Pau=20Monn=C3=A9?= Cc: Andrew Cooper , Paul Durrant , "xen-devel@lists.xenproject.org" List-Id: xen-devel@lists.xenproject.org >>> On 14.01.16 at 09:35, wrote: > El 13/01/16 a les 17.48, Paul Durrant ha escrit: >>> -----Original Message----- >>> From: Jan Beulich [mailto:JBeulich@suse.com] >>> Sent: 13 January 2016 16:39 >>> To: Paul Durrant; Roger Pau Monne >>> Cc: Andrew Cooper; xen-devel@lists.xenproject.org >>> Subject: Re: [PATCH 5/5] x86/HVM: don't setup an intercept handler for IO >>> port 0xcf8 unconditionally >>> >>>>>> On 13.01.16 at 13:32, wrote: >>>> Only intercept accesses to IO port 0xcf8 if there's at least one IOREQ >>>> server, otherwise it makes no sense since the only code that uses the value >>>> stored by hvm_access_cf8 is the IOREQ server. >>> >>> Afaict an ioreq server could also attach subsequently - Paul? >>> >> >> Indeed, ioreq servers can come and go at any time. > > Right, then I will have to prevent hvm_access_cf8 from being added if > the domain is the hardware domain, otherwise it overlaps with the Dom0 > passthrough intercept (handle_pvh_io). Yes, that indeed makes sense. Jan