From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755917Ab3DRNdx (ORCPT ); Thu, 18 Apr 2013 09:33:53 -0400 Received: from mail-bl2lp0211.outbound.protection.outlook.com ([207.46.163.211]:34335 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755103Ab3DRNdw convert rfc822-to-8bit (ORCPT ); Thu, 18 Apr 2013 09:33:52 -0400 X-Forefront-Antispam-Report-Untrusted: CIP:157.56.240.21;KIP:(null);UIP:(null);(null);H:BL2PRD0310HT001.namprd03.prod.outlook.com;R:internal;EFV:INT X-SpamScore: -2 X-BigFish: PS-2(zz98dI9371I542I1432Izz1f42h1fc6h1ee6h1de0h1fdah1202h1e76h1d1ah1d2ahz97hz17326ah8275bh8275dhz31h2a8h668h839h944hd24hf0ah1220h1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h19ceh1ad9h1b0ah9a9j1155h) X-Forefront-Antispam-Report-Untrusted: SFV:SKI;SFS:;DIR:OUT;SFP:;SCL:-1;SRVR:SN2PR03MB063;H:SN2PR03MB061.namprd03.prod.outlook.com;LANG:en; From: KY Srinivasan To: KY Srinivasan , "Michael S. Tsirkin" CC: "olaf@aepfle.de" , "gregkh@linuxfoundation.org" , "jasowang@redhat.com" , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "bp@alien8.de" , Jan Beulich , "hpa@zytor.com" , "apw@canonical.com" , "devel@linuxdriverproject.org" , "tglx@linutronix.de" Subject: RE: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V Thread-Topic: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V Thread-Index: AQHOAnJoFJQhzmD3TUKsF9dq+4jlRZjabzYAgABndUD///hDAIAAE9LQ///2YoCAABF4gP//9RUAAANR4jAAAPGWAAAA7LQAACCB7gAAB4pZEAAEZRWg Date: Thu, 18 Apr 2013 13:30:56 +0000 Message-ID: References: <20130417070616.GA4487@redhat.com> <423ae84de75f4b3587eb2d1a365cbd95@SN2PR03MB061.namprd03.prod.outlook.com> <20130417124852.GD6801@redhat.com> <3b76ebfdb240419aa601309465a4c154@SN2PR03MB061.namprd03.prod.outlook.com> <20130417132523.GB26157@redhat.com> <9ffd83acf6ac4a7bb5d51c95c96e6f50@SN2PR03MB061.namprd03.prod.outlook.com> <20130417134850.GB26335@redhat.com> <0cd5cde572734ea786664accc1a40bea@SN2PR03MB061.namprd03.prod.outlook.com> <516EE0FE02000078000CE422@nat28.tlf.novell.com> <76ae3b714d064ae392332615bfd872d5@SN2PR03MB061.namprd03.prod.outlook.com> <20130418074810.GI13787@redhat.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [98.110.61.163] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-OrganizationHeadersPreserved: SN2PR03MB063.namprd03.prod.outlook.com X-FOPE-CONNECTOR: Id%0$Dn%*$RO%0$TLS%0$FQDN%$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%ZYTOR.COM$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%SUSE.COM$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%ALIEN8.DE$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%LINUTRONIX.DE$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%LINUXDRIVERPROJECT.ORG$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%CANONICAL.COM$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%LINUXFOUNDATION.ORG$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%AEPFLE.DE$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%REDHAT.COM$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%VGER.KERNEL.ORG$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-FOPE-CONNECTOR: Id%59$Dn%KERNEL.ORG$RO%2$TLS%6$FQDN%corpf5vips-237160.customer.frontbridge.com$TlsDn% X-CrossPremisesHeadersPromoted: TK5EX14HUBC107.redmond.corp.microsoft.com X-CrossPremisesHeadersFiltered: TK5EX14HUBC107.redmond.corp.microsoft.com X-Forefront-Antispam-Report: CIP:131.107.125.37;CTRY:US;IPV:CAL;IPV:NLI;EFV:NLI;SFV:NSPM;SFS:(189002)(199002)(51704004)(13464002)(24454001)(377454001)(79102001)(6806003)(81542001)(4396001)(33646001)(23726002)(47736001)(47776003)(54316002)(46406003)(65816001)(54356001)(50466001)(51856001)(77982001)(56776001)(76482001)(50986001)(74502001)(53806001)(49866001)(31966008)(63696002)(46102001)(47446002)(66066001)(44976003)(69226001)(1511001)(80022001)(56816002)(15202345002)(81342001)(16676001)(20776003)(74662001)(47976001)(59766001)(24736002);DIR:OUT;SFP:;SCL:1;SRVR:BY2FFO11HUB031;H:TK5EX14HUBC107.redmond.corp.microsoft.com;RD:InfoDomainNonexistent;MX:1;A:1;LANG:en; X-OriginatorOrg: microsoft.onmicrosoft.com X-Forefront-PRVS: 08200063E9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: devel [mailto:devel-bounces@linuxdriverproject.org] On Behalf Of KY > Srinivasan > Sent: Thursday, April 18, 2013 9:23 AM > To: Michael S. Tsirkin > Cc: olaf@aepfle.de; gregkh@linuxfoundation.org; jasowang@redhat.com; > x86@kernel.org; linux-kernel@vger.kernel.org; bp@alien8.de; Jan Beulich; > hpa@zytor.com; apw@canonical.com; devel@linuxdriverproject.org; > tglx@linutronix.de > Subject: RE: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V > > > > > -----Original Message----- > > From: Michael S. Tsirkin [mailto:mst@redhat.com] > > Sent: Thursday, April 18, 2013 3:48 AM > > To: KY Srinivasan > > Cc: Jan Beulich; olaf@aepfle.de; bp@alien8.de; apw@canonical.com; > > x86@kernel.org; tglx@linutronix.de; devel@linuxdriverproject.org; > > gregkh@linuxfoundation.org; jasowang@redhat.com; linux- > > kernel@vger.kernel.org; hpa@zytor.com > > Subject: Re: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper-V > > > > On Wed, Apr 17, 2013 at 04:28:36PM +0000, KY Srinivasan wrote: > > > > > > > > > > -----Original Message----- > > > > From: Jan Beulich [mailto:JBeulich@suse.com] > > > > Sent: Wednesday, April 17, 2013 11:51 AM > > > > To: KY Srinivasan; Michael S. Tsirkin > > > > Cc: olaf@aepfle.de; bp@alien8.de; apw@canonical.com; x86@kernel.org; > > > > tglx@linutronix.de; devel@linuxdriverproject.org; > > gregkh@linuxfoundation.org; > > > > jasowang@redhat.com; linux-kernel@vger.kernel.org; hpa@zytor.com > > > > Subject: RE: [PATCH 2/3] X86: Add a check to catch Xen emulation of Hyper- > V > > > > > > > > >>> On 17.04.13 at 17:31, KY Srinivasan wrote: > > > > > If Xen were to change where it would not unconditionally emulate Hyper- > V, > > I > > > > > would not be opposed to taking > > > > > this check out. > > > > > > > > But it doesn't do this unconditionally, only upon admin request. > > > > > > >From the discussion we had a couple of months ago, the default setting was > to > > enable > > > Hyper-V emulation for all guests. If this is not the case, we ought to be able to > > drop this. > > > However, I think it is not reasonable to add additional checks (in addition to > > hypervisor check) > > > to customize the run-time in the guest for the specific Hypervisor. > > > > > > Regards, > > > > > > K. Y > > > > Parse error. What are you trying to say? I'm just saying it's best to do > > things in the way that make it possible for Xen to implement hyperv in a > > more complete way in the future and have things just work > > and in a way that does not change guest/hypervisor interface. > > There is no error to parse here. I need to setup the vmbus interrupt before I > can contact the host. As I said I am fine with dropping this check if Xen behavior is > changed appropriately. We have a mechanism for hypervisor detection and a > mechanism for discovering features within a hypervisor. Once we confirm the > existence of a specific hypervisor, we ought to be able to do what is needed for > that hypervisor (unless the hypervisor feature flag precludes it) without having to > go through hoops to discover if we are in a hypervisor emulation mode where > the emulation > may not be complete. In this particular case, the need for VMBUS related > infrastructure cannot be > currently determined via the feature detection mechanism. > > For features that cannot be detected via CPUID feature bits, we can use some > other CPUID based > mechanism to discriminate. For instance in the case under discussion, I could > install > hyperv_callback_vector only if we are on an environment that supports the > vmbus infrastructure. > Unfortunately there is no positive test for this. The best we can do is a negative > test. I could move the > Xen check and conditionally install the hyperv_callback vector. Michael, I think I can address the problem you have raised. I will send a patch out soon. Regards, K. Y > > Regards, > > K. Y > > > > > > > > > > > > Jan > > > > > > > > > > > > > > > > _______________________________________________ > devel mailing list > devel@linuxdriverproject.org > http://driverdev.linuxdriverproject.org/mailman/listinfo/devel >