From mboxrd@z Thu Jan 1 00:00:00 1970 From: Igor Mammedov Subject: Re: [PATCH v2 3/8] nvdimm acpi: introduce _FIT Date: Tue, 11 Oct 2016 13:49:10 +0200 Message-ID: <20161011134910.1988542c@nial.brq.redhat.com> References: <1470984850-66891-1-git-send-email-guangrong.xiao@linux.intel.com> <1470984850-66891-4-git-send-email-guangrong.xiao@linux.intel.com> <20160930151422.6327c7d1@nial.brq.redhat.com> <88933673-0afc-7389-f792-43bd7f6a1bcc@linux.intel.com> <20161010145113.71229994@nial.brq.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, rth@twiddle.net To: Xiao Guangrong Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+gceq-qemu-devel=gmane.org@nongnu.org Sender: "Qemu-devel" List-Id: kvm.vger.kernel.org On Mon, 10 Oct 2016 21:09:30 +0800 Xiao Guangrong wrote: > On 10/10/2016 08:51 PM, Igor Mammedov wrote: > > On Sat, 8 Oct 2016 15:17:14 +0800 > > Xiao Guangrong wrote: > > > >> On 09/30/2016 09:14 PM, Igor Mammedov wrote: > >>> On Fri, 12 Aug 2016 14:54:05 +0800 > >>> Xiao Guangrong wrote: > >>> > >>>> _FIT is required for hotplug support, guest will inquire the updated > >>>> device info from it if a hotplug event is received > >>>> > >>>> As FIT buffer is not completely mapped into guest address space, so a > >>>> new function, Read FIT whose function index is 0xFFFFFFFF, is reserved > >>>> by QEMU to read the piece of FIT buffer. The buffer is concatenated > >>>> before _FIT return > >>> Only issuer of UUID 2F10E7A4-9E91-11E4-89D3-123B93F75CBA can reserve > >>> 0xFFFFFFFF for some purposes. > >>> So spec should be amended first or custom generated UUID should be used. > >> > >> Okay. > >> > >> I will change the changelog to reflect this fact and move the spec update > >> to this patch. > > under spec, I've meant ACPI spec where this UUID is declared > > Er. ACPI spec just said that "0xFFFF is reserved", not sure it will be used > in the future. > > I'd prefer to custom-generated UUID, however, currently the UUID is checked > in OSPM, i.e, QEMU is not able to distinguish other UUIDs, I'd go with custom-generated UUID > so how about > drop the UUID check in ACPI and pass the UUID info to QEMU? It's a bit late to do so as it would be qemu-guest ABI change and one would need to maintain old and new protocol. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41780) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btvYd-0002iV-NV for qemu-devel@nongnu.org; Tue, 11 Oct 2016 07:49:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1btvYY-0003Zr-MZ for qemu-devel@nongnu.org; Tue, 11 Oct 2016 07:49:18 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52542) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1btvYY-0003ZY-FU for qemu-devel@nongnu.org; Tue, 11 Oct 2016 07:49:14 -0400 Date: Tue, 11 Oct 2016 13:49:10 +0200 From: Igor Mammedov Message-ID: <20161011134910.1988542c@nial.brq.redhat.com> In-Reply-To: References: <1470984850-66891-1-git-send-email-guangrong.xiao@linux.intel.com> <1470984850-66891-4-git-send-email-guangrong.xiao@linux.intel.com> <20160930151422.6327c7d1@nial.brq.redhat.com> <88933673-0afc-7389-f792-43bd7f6a1bcc@linux.intel.com> <20161010145113.71229994@nial.brq.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 3/8] nvdimm acpi: introduce _FIT List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Xiao Guangrong Cc: ehabkost@redhat.com, kvm@vger.kernel.org, mst@redhat.com, gleb@kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, pbonzini@redhat.com, dan.j.williams@intel.com, rth@twiddle.net On Mon, 10 Oct 2016 21:09:30 +0800 Xiao Guangrong wrote: > On 10/10/2016 08:51 PM, Igor Mammedov wrote: > > On Sat, 8 Oct 2016 15:17:14 +0800 > > Xiao Guangrong wrote: > > > >> On 09/30/2016 09:14 PM, Igor Mammedov wrote: > >>> On Fri, 12 Aug 2016 14:54:05 +0800 > >>> Xiao Guangrong wrote: > >>> > >>>> _FIT is required for hotplug support, guest will inquire the updated > >>>> device info from it if a hotplug event is received > >>>> > >>>> As FIT buffer is not completely mapped into guest address space, so a > >>>> new function, Read FIT whose function index is 0xFFFFFFFF, is reserved > >>>> by QEMU to read the piece of FIT buffer. The buffer is concatenated > >>>> before _FIT return > >>> Only issuer of UUID 2F10E7A4-9E91-11E4-89D3-123B93F75CBA can reserve > >>> 0xFFFFFFFF for some purposes. > >>> So spec should be amended first or custom generated UUID should be used. > >> > >> Okay. > >> > >> I will change the changelog to reflect this fact and move the spec update > >> to this patch. > > under spec, I've meant ACPI spec where this UUID is declared > > Er. ACPI spec just said that "0xFFFF is reserved", not sure it will be used > in the future. > > I'd prefer to custom-generated UUID, however, currently the UUID is checked > in OSPM, i.e, QEMU is not able to distinguish other UUIDs, I'd go with custom-generated UUID > so how about > drop the UUID check in ACPI and pass the UUID info to QEMU? It's a bit late to do so as it would be qemu-guest ABI change and one would need to maintain old and new protocol.