From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from TX2EHSOBE005.bigfish.com (tx2ehsobe003.messaging.microsoft.com [65.55.88.13]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (Client CN "mail.global.frontbridge.com", Issuer "Cybertrust SureServer Standard Validation CA" (verified OK)) by ozlabs.org (Postfix) with ESMTPS id 8CFF6B6F7A for ; Tue, 12 Jul 2011 01:45:54 +1000 (EST) Message-ID: <4E1B1AAB.8010301@freescale.com> Date: Mon, 11 Jul 2011 10:45:47 -0500 From: Timur Tabi MIME-Version: 1.0 To: Yoder Stuart-B08248 Subject: Re: RFC: top level compatibles for virtual platforms References: <9F6FE96B71CF29479FF1CDC8046E150316EAB6@039-SN1MPN1-003.039d.mgd.msft.net> <9F6FE96B71CF29479FF1CDC8046E150316F97F@039-SN1MPN1-003.039d.mgd.msft.net> In-Reply-To: <9F6FE96B71CF29479FF1CDC8046E150316F97F@039-SN1MPN1-003.039d.mgd.msft.net> Content-Type: text/plain; charset="ISO-8859-1" Cc: Wood Scott-B07421 , Alexander Graf , "linuxppc-dev@ozlabs.org" , Gala Kumar-B11780 List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Yoder Stuart-B08248 wrote: > We're talking about what would be meaningful to Linux as a guest on > this platform here-- Corenet-based SoCs are similar > in various ways, like using msgsnd for IPIs, having external proxy > support, etc. > > A corenet platform created by a QEMU/KVM looks similar > to other corenet SoCs. So, I'm trying to find some generic > compatible string that describes this platform. Is there a list of these features that are 100% guaranteed to belong to a corenet platform? I'm just not comfortable using "corenet" as a basis for a feature set that has nothing to do with coherency. >> Also, if these are KVM creations, shouldn't there be a "kvm" in the compatible string >> somewhere? > > There is nothing KVM specific about these platforms. Any hypervisor > could create a similar virtual machine. True, but I think we're on a slippery slope, here. Virtualization allows us to create "virtual platforms" that are not well defined. Linux requires a unique compatible string for each platform. That's easy when we ship a reference board that has a unique name and a fixed, well-defined set of features. But with these virtual platforms, what does the name mean? I guess my point is back to the name "corenet". That just doesn't mean anything to me, and I don't think it means much to anyone else, either. That's why I think that maybe "kvm" should be in the string, to at least indicate that it's a virtualized environment. > A guest OS can determine specific info about the hypervisor it is > running on by looking at the /hypervisor node on the device > tree. > > We could put a generic -hv extension to indicate that this is > a virtual platform. > > "mpc85xx-hv" > "corenet-32-hv" > "corenet-64-hv" That's an improvement, but I wonder if we should just keep doing what we do with Topaz: take the actual hardware platform and add -hv to it. Of course, that conflicts with Topaz at the moment. -- Timur Tabi Linux kernel developer at Freescale -- Timur Tabi Linux kernel developer at Freescale