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.campb...@citrix.com] > > > Sent: Friday, May 09, 2014 5:57 PM > > > To: Gonglei (Arei) > > > Cc: Jan Beulich; xen-de...@lists.xen.org; anthony.per...@citrix.com; > > > stefano.stabell...@eu.citrix.com; johannes.kra...@googlemail.com; Gaowei > > > (UVP); Hanweidong (Randy); Huangweidong (C); ke...@koconnor.net; > > > fabio.fant...@m2r.biz; qemu-devel@nongnu.org; m...@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-de...@lists.xen.org > http://lists.xen.org/xen-devel