From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:44650) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gubSQ-0001ND-9J for qemu-devel@nongnu.org; Fri, 15 Feb 2019 06:15:04 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gubSO-0002p2-9x for qemu-devel@nongnu.org; Fri, 15 Feb 2019 06:15:02 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47574) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gubSN-0002YX-T7 for qemu-devel@nongnu.org; Fri, 15 Feb 2019 06:15:00 -0500 Date: Fri, 15 Feb 2019 12:14:32 +0100 From: Igor Mammedov Message-ID: <20190215121432.6823da96@Igors-MacBook-Pro.local> In-Reply-To: <20190214205331.pvht6oqynndc2k7u@master> References: <20190214005225.24048-1-richardw.yang@linux.intel.com> <20190214122527.5d2fcab8@redhat.com> <20190214205331.pvht6oqynndc2k7u@master> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] i386, acpi: check acpi_memory_hotplug capacity in pre_plug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wei Yang Cc: Wei Yang , qemu-devel@nongnu.org, mst@redhat.com On Thu, 14 Feb 2019 20:53:31 +0000 Wei Yang wrote: > On Thu, Feb 14, 2019 at 12:25:27PM +0100, Igor Mammedov wrote: > >On Thu, 14 Feb 2019 08:52:25 +0800 > >Wei Yang wrote: > > > >> Currently we do device realization like below: > >> > >> hotplug_handler_pre_plug() > >> dc->realize() > >> hotplug_handler_plug() > >> > >> Before we do device realization and plug, we would allocate necessary > >> resources and check the capacity. > >'capacity' probably is not right word to use here > >maybe s/the capacity/if 'memory-hotplug-support' property is enabled/ > > > >> > >> While we leave acpi_memory_hotplug capacity check in the last step. This > >wouldn't use 'leave' and 'capacity' here either, pls rephrase. > > > >> looks not comply with current architecture and does some unnecessary > >s/looks not/doesn't/ > >> work. > >add more explanation about 'unnecessary work'. > >problem as I see it, is that after successful pc_dimm_plug() > >we get into piix4_device_plug_cb() and since > > s->acpi_memory_hotplug.is_enabled == false > >and all other 'if' conditions also false we would endup > >at g_assert_not_reached() causing QEMU crash in piix4 case > >and with error_abort up the call chain in case of ich9. > > > > Thanks Igor, I rephrase above change log like this. Does this look > better to you now? > > Before we do device realization and plug, we would allocate s/would/should/ > necessary resources and check if memory-hotplug-support property is > enabled. > > In piix4 and ich9, the acpi_memory_hotplug property is checked in s/in/at the/ > plug stage, this doesn't comply with current architecture. This drop ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > means we have prepared everything and even do pc_dimm_plug() ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ that device has been realized and mapped into guest address space 'pc_dimm_plug()' by the time acpi plug handler is called, where it might fail and crash QEMU due to reaching g_assert_not_reached() (piix4) or error_abort (ich9). or something like this, I'm not native speaker either so CC Eric Blake on next respin so he could check commit message. > successfuly, but failed at last because > acpi_memory_hotplug.is_enabled == false. Which is worse is in piix4, > this endup at g_assert_not_reached() and cause QEMU crash. > > > >> This patch abstract the check on acpi_memory_hotplug capacity in > >> pre_plug stage. > >> > >> Signed-off-by: Wei Yang > >> --- > >> hw/acpi/piix4.c | 14 ++++++++++++-- > >> hw/i386/pc.c | 8 ++++++++ > >doesn't look complete, why did you skip on similar code in ich9 > >(Q35 machine)? > > > > You are right, I missed this part. > > >> 2 files changed, 20 insertions(+), 2 deletions(-) > >> > >> diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c > >> index e330f24c71..c97b747496 100644 > >> --- a/hw/acpi/piix4.c > >> +++ b/hw/acpi/piix4.c > >> @@ -370,13 +370,22 @@ static void piix4_pm_powerdown_req(Notifier *n, void *opaque) > >> acpi_pm1_evt_power_down(&s->ar); > >> } > >> > >> +static void piix4_device_pre_plug_cb(HotplugHandler *hotplug_dev, > >> + DeviceState *dev, Error **errp) > >> +{ > >> + PIIX4PMState *s = PIIX4_PM(hotplug_dev); > >> + > >> + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) && > >> + !s->acpi_memory_hotplug.is_enabled) > >> + error_setg(errp, > >> + "memory hotplug is not enabled: PIIX4 memory hotplug disabled"); > >> +} > >> static void piix4_device_plug_cb(HotplugHandler *hotplug_dev, > >> DeviceState *dev, Error **errp) > >> { > >> PIIX4PMState *s = PIIX4_PM(hotplug_dev); > >> > >> - if (s->acpi_memory_hotplug.is_enabled && > >> - object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) { > >> + if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) { > >> if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) { > >> nvdimm_acpi_plug_cb(hotplug_dev, dev); > >> } else { > >> @@ -702,6 +711,7 @@ static void piix4_pm_class_init(ObjectClass *klass, void *data) > >> */ > >> dc->user_creatable = false; > >> dc->hotpluggable = false; > >> + hc->pre_plug = piix4_device_pre_plug_cb; > >> hc->plug = piix4_device_plug_cb; > >> hc->unplug_request = piix4_device_unplug_request_cb; > >> hc->unplug = piix4_device_unplug_cb; > >> diff --git a/hw/i386/pc.c b/hw/i386/pc.c > >> index 734d3268fa..3c6eed0cd3 100644 > >> --- a/hw/i386/pc.c > >> +++ b/hw/i386/pc.c > >> @@ -1662,6 +1662,7 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > >> const PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms); > >> const bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM); > >> const uint64_t legacy_align = TARGET_PAGE_SIZE; > >> + HotplugHandlerClass *hhc; > >> > >> /* > >> * When -no-acpi is used with Q35 machine type, no ACPI is built, > >> @@ -1674,6 +1675,13 @@ static void pc_memory_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev, > >> return; > >> } > >> > >> + /* > >> + * Check acpi_dev memory hotplug capacity > >> + */ > >> + hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev); > >> + if (hcc->pre_plug) > >> + hhc->pre_plug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, errp); > >use hotplug_handler_pre_plug() instead of open-coding check > > > > Thanks, will fix this. > > >> if (is_nvdimm && !pcms->acpi_nvdimm_state.is_enabled) { > >> error_setg(errp, "nvdimm is not enabled: missing 'nvdimm' in '-M'"); > >> return; > > >