From: Xiao Guangrong <guangrong.xiao@linux.intel.com> To: Igor Mammedov <imammedo@redhat.com> Cc: pbonzini@redhat.com, gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org Subject: Re: [PATCH v2 6/8] pc: memhp: do not export nvdimm's memory via _CRS Date: Sat, 8 Oct 2016 15:42:41 +0800 [thread overview] Message-ID: <f5982500-1e62-850c-e357-49daf1cfd555@linux.intel.com> (raw) In-Reply-To: <20161003152154.03766fc1@nial.brq.redhat.com> On 10/03/2016 09:21 PM, Igor Mammedov wrote: > On Fri, 12 Aug 2016 14:54:08 +0800 > Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote: > >> nvdimm's memory info can not exported via _CRS, instead, it is reported >> by NFIT/FIT >> >> This patch let _CRS return zero for both memory address and memory size >> if it is a nvdimm device inserted to the slot > I'm not sure if it's right thing to do. > As it's relatively new, spec isn't clear about NVDIMM hotplug > process and how it's related to PNP0C80 memory devices. > > The thing is that notify to PNP0C80 will trigger regular > memory hotplug which would expect a valid _CRS and > I won't even try to predict reaction of different guests > on such behavior. > > So far exposing NFIT was sufficient for guest to work with > NVDIMMs at startup. So I'd assume NVDIMM_ROOT._FIT() would > provide sufficient info to hot-plug NVDIMM and allow > NVDIMM driver to handle it. > > The only case of using PNP0C80 with NVDIMM, I'd imagine, is > when one would like to expose NVDIMM as conventional RAM and > make guest OS use it as such, which is probably not what you'd > intended do here. > > Question is should/could NVDIMM hotplug work without using > PNP0C80? Some confusion i got when i was reading ACPI spec. I thing you are right that notifying memory device (PNP0C80) is needed only if the nvdimm is trying to export conventional RAM. > > One could reuse/share memhotplug GPE._E03 to notify NVDIMM_ROOT > but even that is not necessary as NVDIMM has its own QEMU<->guest > interface and could just take the next free _E04 handler. > So I'd suggest to redo this and 7/8 patches to implement > independent (of memhotplug) NVDIMM hotplug as a starting point. Based on ACPI Spec, the memory device (PNP0C80) and nvdimm device is notified by the same interruption: Scope (\_GPE) { Method (_L00) { Notify (\_SB.NVDR, 0x80) // Notify to NVDIMM root device Notify (\_SB.MEM0, 1) // Device Check to Memory Module } } So, it is better to reuse _E03 and only notify NVDIMM device if the hotplug event is triggered on a slot with nvdimm device attached?
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From: Xiao Guangrong <guangrong.xiao@linux.intel.com> To: Igor Mammedov <imammedo@redhat.com> Cc: pbonzini@redhat.com, gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com, mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com, dan.j.williams@intel.com, kvm@vger.kernel.org, qemu-devel@nongnu.org Subject: Re: [Qemu-devel] [PATCH v2 6/8] pc: memhp: do not export nvdimm's memory via _CRS Date: Sat, 8 Oct 2016 15:42:41 +0800 [thread overview] Message-ID: <f5982500-1e62-850c-e357-49daf1cfd555@linux.intel.com> (raw) In-Reply-To: <20161003152154.03766fc1@nial.brq.redhat.com> On 10/03/2016 09:21 PM, Igor Mammedov wrote: > On Fri, 12 Aug 2016 14:54:08 +0800 > Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote: > >> nvdimm's memory info can not exported via _CRS, instead, it is reported >> by NFIT/FIT >> >> This patch let _CRS return zero for both memory address and memory size >> if it is a nvdimm device inserted to the slot > I'm not sure if it's right thing to do. > As it's relatively new, spec isn't clear about NVDIMM hotplug > process and how it's related to PNP0C80 memory devices. > > The thing is that notify to PNP0C80 will trigger regular > memory hotplug which would expect a valid _CRS and > I won't even try to predict reaction of different guests > on such behavior. > > So far exposing NFIT was sufficient for guest to work with > NVDIMMs at startup. So I'd assume NVDIMM_ROOT._FIT() would > provide sufficient info to hot-plug NVDIMM and allow > NVDIMM driver to handle it. > > The only case of using PNP0C80 with NVDIMM, I'd imagine, is > when one would like to expose NVDIMM as conventional RAM and > make guest OS use it as such, which is probably not what you'd > intended do here. > > Question is should/could NVDIMM hotplug work without using > PNP0C80? Some confusion i got when i was reading ACPI spec. I thing you are right that notifying memory device (PNP0C80) is needed only if the nvdimm is trying to export conventional RAM. > > One could reuse/share memhotplug GPE._E03 to notify NVDIMM_ROOT > but even that is not necessary as NVDIMM has its own QEMU<->guest > interface and could just take the next free _E04 handler. > So I'd suggest to redo this and 7/8 patches to implement > independent (of memhotplug) NVDIMM hotplug as a starting point. Based on ACPI Spec, the memory device (PNP0C80) and nvdimm device is notified by the same interruption: Scope (\_GPE) { Method (_L00) { Notify (\_SB.NVDR, 0x80) // Notify to NVDIMM root device Notify (\_SB.MEM0, 1) // Device Check to Memory Module } } So, it is better to reuse _E03 and only notify NVDIMM device if the hotplug event is triggered on a slot with nvdimm device attached?
next prev parent reply other threads:[~2016-10-08 7:49 UTC|newest] Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-08-12 6:54 [PATCH v2 0/8] nvdimm: hotplug support Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 1/8] acpi nvdimm: fix wrong buffer size returned by DSM method Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-20 14:07 ` Igor Mammedov 2016-09-20 14:07 ` [Qemu-devel] " Igor Mammedov 2016-09-20 15:14 ` Michael S. Tsirkin 2016-09-20 15:14 ` [Qemu-devel] " Michael S. Tsirkin 2016-09-20 16:23 ` Igor Mammedov 2016-09-21 5:30 ` Xiao Guangrong 2016-09-21 5:30 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 2/8] nvdimm acpi: prebuild nvdimm devices for available slots Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-21 11:48 ` Igor Mammedov 2016-09-21 11:48 ` [Qemu-devel] " Igor Mammedov 2016-09-22 2:43 ` Xiao Guangrong 2016-09-22 2:43 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 3/8] nvdimm acpi: introduce _FIT Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-30 13:14 ` Igor Mammedov 2016-09-30 13:14 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:17 ` Xiao Guangrong 2016-10-08 7:17 ` [Qemu-devel] " Xiao Guangrong 2016-10-10 12:51 ` Igor Mammedov 2016-10-10 12:51 ` [Qemu-devel] " Igor Mammedov 2016-10-10 13:09 ` Xiao Guangrong 2016-10-10 13:09 ` [Qemu-devel] " Xiao Guangrong 2016-10-11 11:49 ` Igor Mammedov 2016-10-11 11:49 ` [Qemu-devel] " Igor Mammedov 2016-10-12 8:20 ` Xiao Guangrong 2016-10-12 8:20 ` [Qemu-devel] " Xiao Guangrong 2016-10-13 13:33 ` Igor Mammedov 2016-10-14 7:43 ` Xiao Guangrong 2016-10-14 11:59 ` Igor Mammedov 2016-08-12 6:54 ` [PATCH v2 4/8] nvdimm acpi: implement Read FIT function Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-30 13:17 ` Igor Mammedov 2016-09-30 13:17 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:17 ` Xiao Guangrong 2016-10-08 7:17 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 5/8] pc-dimm: introduce prepare_unplug() callback Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-10-03 9:45 ` Igor Mammedov 2016-10-03 9:45 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:20 ` Xiao Guangrong 2016-10-08 7:20 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 6/8] pc: memhp: do not export nvdimm's memory via _CRS Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-10-03 13:21 ` Igor Mammedov 2016-10-03 13:21 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:42 ` Xiao Guangrong [this message] 2016-10-08 7:42 ` Xiao Guangrong 2016-10-10 12:47 ` Igor Mammedov 2016-10-10 12:47 ` [Qemu-devel] " Igor Mammedov 2016-10-10 13:10 ` Xiao Guangrong 2016-10-10 13:10 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 7/8] pc: acpi: memhp: nvdimm hotplug support Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 6:54 ` [PATCH v2 8/8] nvdimm docs: add nvdimm Read FIT function Xiao Guangrong 2016-08-12 6:54 ` [Qemu-devel] " Xiao Guangrong 2016-09-30 14:03 ` Igor Mammedov 2016-09-30 14:03 ` [Qemu-devel] " Igor Mammedov 2016-10-08 7:18 ` Xiao Guangrong 2016-10-08 7:18 ` [Qemu-devel] " Xiao Guangrong 2016-08-12 8:35 ` [PATCH v2 0/8] nvdimm: hotplug support Stefan Hajnoczi 2016-08-12 8:35 ` [Qemu-devel] " Stefan Hajnoczi 2016-08-12 15:13 ` Igor Mammedov 2016-08-12 15:13 ` [Qemu-devel] " Igor Mammedov 2016-09-12 7:33 ` Xiao Guangrong 2016-09-12 7:33 ` [Qemu-devel] " Xiao Guangrong 2016-09-12 12:22 ` Igor Mammedov 2016-08-18 17:47 ` Dan Williams 2016-08-18 17:47 ` [Qemu-devel] " Dan Williams 2016-08-18 18:54 ` Vishal Verma 2016-08-18 18:54 ` [Qemu-devel] " Vishal Verma 2016-08-19 3:40 ` Xiao Guangrong 2016-08-19 3:40 ` [Qemu-devel] " Xiao Guangrong 2016-08-19 3:46 ` Xiao Guangrong 2016-08-19 3:46 ` [Qemu-devel] " Xiao Guangrong 2016-08-19 5:14 ` Dan Williams 2016-08-19 5:14 ` [Qemu-devel] " Dan Williams 2016-10-03 13:48 ` Igor Mammedov 2016-10-08 8:34 ` Xiao Guangrong 2016-10-10 12:59 ` Igor Mammedov 2016-10-10 13:57 ` Xiao Guangrong 2016-10-11 12:32 ` Igor Mammedov 2016-10-12 10:19 ` Xiao Guangrong
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