From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: 0xB16B00B5? Really? (was Re: Move hyperv out of the drivers/staging/ directory) Date: Thu, 19 Jul 2012 18:18:04 -0500 Message-ID: <500895AC.7020303@codemonkey.ws> References: <6E21E5352C11B742B20C142EB499E048081E935D@TK5EX14MBXC124.redmond.corp.microsoft.com> <20110922173618.GA5624@suse.de> <6E21E5352C11B742B20C142EB499E048081EB789@TK5EX14MBXC124.redmond.corp.microsoft.com> <20111004170415.GA1320@suse.de> <6E21E5352C11B742B20C142EB499E048081EB86F@TK5EX14MBXC124.redmond.corp.microsoft.com> <20111004193414.GA15672@suse.de> <4FFFF711.8040003@redhat.com> <426367E2313C2449837CD2DE46E7EAF923547292@SN2PRD0310MB382.namprd03.prod.outlook.com> <20120719210709.GA32031@kroah.com> <426367E2313C2449837CD2DE46E7EAF9235475EE@SN2PRD0310MB382.namprd03.prod.outlook.com> <20120719220142.GA1513@kroah.com> <426367E2313C2449837CD2DE46E7EAF923547620@SN2PRD0310MB382.namprd03.prod.outlook.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <426367E2313C2449837CD2DE46E7EAF923547620@SN2PRD0310MB382.namprd03.prod.outlook.com> Sender: linux-kernel-owner@vger.kernel.org To: KY Srinivasan Cc: "Greg KH (gregkh@linuxfoundation.org)" , Paolo Bonzini , "devel@linuxdriverproject.org" , "linux-kernel@vger.kernel.org" , "virtualization@lists.osdl.org" List-Id: virtualization@lists.linuxfoundation.org On 07/19/2012 05:30 PM, KY Srinivasan wrote: > > >> -----Original Message----- >> From: Greg KH (gregkh@linuxfoundation.org) >> [mailto:gregkh@linuxfoundation.org] >> Sent: Thursday, July 19, 2012 6:02 PM >> To: KY Srinivasan >> Cc: Paolo Bonzini; devel@linuxdriverproject.org; linux-kernel@vger.kernel.org; >> virtualization@lists.osdl.org >> Subject: Re: 0xB16B00B5? Really? (was Re: Move hyperv out of the >> drivers/staging/ directory) >> >> On Thu, Jul 19, 2012 at 09:22:53PM +0000, KY Srinivasan wrote: >>> >>> >>>> -----Original Message----- >>>> From: Greg KH (gregkh@linuxfoundation.org) >>>> [mailto:gregkh@linuxfoundation.org] >>>> Sent: Thursday, July 19, 2012 5:07 PM >>>> To: KY Srinivasan >>>> Cc: Paolo Bonzini; devel@linuxdriverproject.org; linux- >> kernel@vger.kernel.org; >>>> virtualization@lists.osdl.org >>>> Subject: Re: 0xB16B00B5? Really? (was Re: Move hyperv out of the >>>> drivers/staging/ directory) >>>> >>>> On Thu, Jul 19, 2012 at 02:11:47AM +0000, KY Srinivasan wrote: >>>>> >>>>> >>>>>> -----Original Message----- >>>>>> From: Paolo Bonzini [mailto:paolo.bonzini@gmail.com] On Behalf Of Paolo >>>>>> Bonzini >>>>>> Sent: Friday, July 13, 2012 6:23 AM >>>>>> To: KY Srinivasan >>>>>> Cc: Greg KH; devel@linuxdriverproject.org; linux-kernel@vger.kernel.org; >>>>>> virtualization@lists.osdl.org >>>>>> Subject: 0xB16B00B5? Really? (was Re: Move hyperv out of the >>>> drivers/staging/ >>>>>> directory) >>>>>> >>>>>> Il 04/10/2011 21:34, Greg KH ha scritto: >>>>>>> diff --git a/drivers/staging/hv/hyperv_vmbus.h >>>> b/drivers/hv/hyperv_vmbus.h >>>>>>> similarity index 99% >>>>>>> rename from drivers/staging/hv/hyperv_vmbus.h >>>>>>> rename to drivers/hv/hyperv_vmbus.h >>>>>>> index 3d2d836..8261cb6 100644 >>>>>>> --- a/drivers/staging/hv/hyperv_vmbus.h >>>>>>> +++ b/drivers/hv/hyperv_vmbus.h >>>>>>> @@ -28,8 +28,7 @@ >>>>>>> #include >>>>>>> #include >>>>>>> #include >>>>>>> - >>>>>>> -#include "hyperv.h" >>>>>>> +#include >>>>>>> >>>>>>> /* >>>>>>> * The below CPUID leaves are present if >>>>>> VersionAndFeatures.HypervisorPresent >>>>>> >>>>>> git's rename detection snips away this gem: >>>>>> >>>>>> +#define HV_LINUX_GUEST_ID_LO 0x00000000 >>>>>> +#define HV_LINUX_GUEST_ID_HI 0xB16B00B5 >>>>>> +#define HV_LINUX_GUEST_ID (((u64)HV_LINUX_GUEST_ID_HI >>>>>> << 32) | \ >>>>>> + HV_LINUX_GUEST_ID_LO) >>>>>> >>>>>> Somone was trying to be funny, I guess. >>>>>> >>>>>> KY, I suppose you have access to Hyper-V code or can ask someone who >>>> does. >>>>>> Is this signature actually used in the Hyper-V host code? >>>>> >>>>> Paolo, >>>>> >>>>> As I noted earlier, this is just a guest ID that needs to be registered with the >>>>> hypervisor. Thanks for reporting this issue and on behalf of Microsoft, I >> would >>>>> like to apologize for this offensive string. I have submitted a patch to fix this >>>> issue. >>>> >>>> You only changed it to be in decimal, you did not change the id at all. >>>> Is there some reason why you can not change it? You said there was a >>>> reserved range of ids that could be used, perhaps just pick another one? >>>> What is the valid range that can be used here? >>> >>> Greg, >>> >>> As you know, this ID has been in use for a long time now. While the hypervisor >>> does not interpret the guest ID that is registered, I am not sure what >> dependencies >>> there might be on this value. >> >> Could you please go find out the answer to this? > > That is easier said than done. I have sent emails out asking this very question and I have > not received a definitive answer yet. Not knowing if and when I can get a definitive > answer here, I chose the least risky approach in my patch. >> >> If, as you originally stated, there is a range of values we can use, >> then we should probably use another one, right? > > On the Windows side this ID namespace is managed well. However on the Linux > side, we have really had this current ID in use for almost five years now. I am not > aware of any pool of IDs available for Linux usage except that Linux IDs be distinct from > the guest IDs in use by MSFT operating systems. If I were to change the guest ID, I would > probably want to comply with the MSFT guidance on constructing these IDs (although not > all fields may be relevant for Linux). Presumably, Hyper-V can deal with unexpected values here, no? Otherwise, it wouldn't be future proof against new types of guests. So worst case scenario, Hyper-V disables optimizations on Linux guests that report then new ID until they patch Hyper-V to know about the new ID. That seems like a reasonable trade off to me. I'm sure there's sufficient incentive to patch Hyper-V for this at Microsoft... Regards, Anthony Liguori > > Regards, > > K. Y > > >