From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33525) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Wikoc-0003qd-7e for qemu-devel@nongnu.org; Fri, 09 May 2014 09:26:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WikoX-00008p-1l for qemu-devel@nongnu.org; Fri, 09 May 2014 09:26:18 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:31208) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WikoW-00008l-S9 for qemu-devel@nongnu.org; Fri, 09 May 2014 09:26:12 -0400 Date: Fri, 9 May 2014 09:25:53 -0400 From: Konrad Rzeszutek Wilk Message-ID: <20140509132553.GA3057@phenom.dumpdata.com> References: <1399625235-8216-1-git-send-email-arei.gonglei@huawei.com> <536CBD840200007800010D2D@mail.emea.novell.com> <33183CC9F5247A488A2544077AF19020815E7487@SZXEMA503-MBS.china.huawei.com> <1399629430.9513.143.camel@kazak.uk.xensource.com> <33183CC9F5247A488A2544077AF19020815E74DA@SZXEMA503-MBS.china.huawei.com> <1399631195.9513.149.camel@kazak.uk.xensource.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1399631195.9513.149.camel@kazak.uk.xensource.com> Subject: Re: [Qemu-devel] [Xen-devel] [PATCH v4] Hvmloader: Modify ACPI to only supply _EJ0 methods for PCIslots that support hotplug by runtime patching List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ian Campbell , paul.durrant@citrix.com Cc: "kevin@koconnor.net" , "Huangweidong (C)" , "Hanweidong (Randy)" , "stefano.stabellini@eu.citrix.com" , "qemu-devel@nongnu.org" , "xen-devel@lists.xen.org" , "fabio.fantoni@m2r.biz" , "anthony.perard@citrix.com" , "Gonglei (Arei)" , "mst@redhat.com" , Jan Beulich , "johannes.krampf@googlemail.com" , "Gaowei (UVP)" On Fri, May 09, 2014 at 11:26:35AM +0100, Ian Campbell wrote: > On Fri, 2014-05-09 at 10:15 +0000, Gonglei (Arei) wrote: > > Hi, > > > > First, please forgive me for my bad English. > > It's so sad. > > > > > -----Original Message----- > > > From: Ian Campbell [mailto:Ian.Campbell@citrix.com] > > > Sent: Friday, May 09, 2014 5:57 PM > > > To: Gonglei (Arei) > > > Cc: Jan Beulich; xen-devel@lists.xen.org; anthony.perard@citrix.com; > > > stefano.stabellini@eu.citrix.com; johannes.krampf@googlemail.com; Gaowei > > > (UVP); Hanweidong (Randy); Huangweidong (C); kevin@koconnor.net; > > > fabio.fantoni@m2r.biz; qemu-devel@nongnu.org; mst@redhat.com > > > Subject: Re: [PATCH v4] Hvmloader: Modify ACPI to only supply _EJ0 methods > > > for PCIslots that support hotplug by runtime patching > > > > > > On Fri, 2014-05-09 at 09:45 +0000, Gonglei (Arei) wrote: > > > > > And it also seem pretty pointless to send a v4 without addressing > > > > > all comments you got on v3. > > > > > > > > > I don't think so. I have absorbed Ian's all suggestion on v3. And for other > > > > questions have been answered too, in despite of is me or not. > > > > > > Actually you haven't answered "Why is runtime patching the only > > > option here?" which was originally phrased as: > > > > > Which appears to involve an awful lot of jumping through hoops... Please > > > > > can you explain why it is necessary, as opposed to e.g. using a dynamic > > > > > set of SSDTs? > > > > > Ian, I understand your mean now, which consider our method to address > > this issue is maybe unnecessary, right? And you suggest us to use a dynamic > > set of SSDTs. > > Really what I'm asking is what set of constraints and requirements led > you to this particular solution. > > I think the method seems complicated, and I'd therefore like to know why > it was preferred over other alternatives, or perhaps why it is the only > option. > > > TBH I don't know more about the dynamic SSDTs, if you have any details, > > tell me please, thanks in advance! > > I'm not an ACPI expert, but AIUI an SSDT is essentially a little piece > of DSDT which is grafted onto the main DSDT at runtime by the OSPM. They > make it somewhat easier for BIOS (or ACPI table) authors to include or > exclude functionality at runtime, perhaps on a physical system in > response to a user changing something in the BIOS setup screens. In Xen > we appear to use SSDTs for HPET, TPM and S3/S4 functionality, depending > on the guest configuration > (hvmloader/acpi/build.c:construct_secondary_tables()). Can it be used to patch the DSDT? Or were you (Ian) thinking that the bulk of the ACPI PCI stuff can be moved there ? How would this work with the 'secondary emulator' patches that do all of this PCI hotplug in the hypervisor? (CC-ing the author of said patches). > > Ian. > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel