From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1NchsA-0001rz-VI for qemu-devel@nongnu.org; Wed, 03 Feb 2010 11:14:35 -0500 Received: from [199.232.76.173] (port=60521 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Nchs9-0001pr-6m for qemu-devel@nongnu.org; Wed, 03 Feb 2010 11:14:33 -0500 Received: from Debian-exim by monty-python.gnu.org with spam-scanned (Exim 4.60) (envelope-from ) id 1Nchs7-00013D-Da for qemu-devel@nongnu.org; Wed, 03 Feb 2010 11:14:33 -0500 Received: from e1.ny.us.ibm.com ([32.97.182.141]:57802) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1Nchs6-00012t-QO for qemu-devel@nongnu.org; Wed, 03 Feb 2010 11:14:31 -0500 Received: from d01relay05.pok.ibm.com (d01relay05.pok.ibm.com [9.56.227.237]) by e1.ny.us.ibm.com (8.14.3/8.13.1) with ESMTP id o13GArZQ006114 for ; Wed, 3 Feb 2010 11:10:53 -0500 Received: from d03av05.boulder.ibm.com (d03av05.boulder.ibm.com [9.17.195.85]) by d01relay05.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o13GEQ4r098340 for ; Wed, 3 Feb 2010 11:14:26 -0500 Received: from d03av05.boulder.ibm.com (loopback [127.0.0.1]) by d03av05.boulder.ibm.com (8.14.3/8.13.1/NCO v10.0 AVout) with ESMTP id o13GEPX6017481 for ; Wed, 3 Feb 2010 09:14:25 -0700 Message-ID: <4B69A0DF.4040908@linux.vnet.ibm.com> Date: Wed, 03 Feb 2010 10:14:23 -0600 From: Anthony Liguori MIME-Version: 1.0 Subject: Re: [Qemu-devel] [Patch] Support translating Guest physical address to Host virtual address. References: <4B60B28A.40400@linux.vnet.ibm.com> <1264631460.29051.35.camel@w-amax.beaverton.ibm.com> <4B697D04.7070507@linux.vnet.ibm.com> <46D41A8912DCCF4FB93FA509BD00C63101E79CA0@irsmsx002.ger.corp.intel.com> <4B6986F6.5000808@linux.vnet.ibm.com> <46D41A8912DCCF4FB93FA509BD00C63101E79E14@irsmsx002.ger.corp.intel.com> In-Reply-To: <46D41A8912DCCF4FB93FA509BD00C63101E79E14@irsmsx002.ger.corp.intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Kleen, Andi" Cc: "lmr@redhat.com" , "Li, Haicheng" , Max Asbock , "qemu-devel@nongnu.org" , "Zheng, Jiajia" , "You, Yongkang" , "avi@redhat.com" On 02/03/2010 09:49 AM, Kleen, Andi wrote: > >> Yeah, but if we put a feature in qemu, we need to be able to >> support it >> for anyone who wants to use it. >> > It's useful for anyone who wants to use it for testing purposes. > And it's useful to make sure the qemu/kernel/kvm machine check > injection code works. > > >> Adding something for a very particular test suite that won't work in >> normal circumstances is just asking for trouble IMHO. >> > RAS features generally need associated testing/injection hooks, > otherwise they don't get tested regularly enough and bitrot. > > >> I still don't really understand all the pieces that are >> involved here. >> Why do we need a guest physical address? Are we testing >> reflecting MCEs >> > >from the host into a guest? Since that functionality isn't in qemu > >> aren't we putting the cart before the horse here? >> > qemu has support for triggering MCEs on the monitor. > > Also the KVM code base has support for forwarding the MCEs automatically. > KVM has all of the information you need (guest physical -> host physical mapping). It can also pin the mapping making it much safer to interface at that level. You should probably add an ioctl interface to KVM to get a host physical from a given guest physical and then use that to do the MCE injection. You would need to write a little helper tool and you would need a way to get an fd for an existing guest. Regards, Anthony Liguori But then it's not a user visible interface. > -Andi >