From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:43839) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gzMQO-0008Sx-E3 for qemu-devel@nongnu.org; Thu, 28 Feb 2019 09:12:37 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gzMQM-0002Kz-GN for qemu-devel@nongnu.org; Thu, 28 Feb 2019 09:12:36 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43478) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gzMQJ-0002I1-Rw for qemu-devel@nongnu.org; Thu, 28 Feb 2019 09:12:32 -0500 Date: Thu, 28 Feb 2019 15:12:21 +0100 From: Igor Mammedov Message-ID: <20190228151221.5909ff92@redhat.com> In-Reply-To: <20190228011325.GA5515@richard> References: <20190225010708.27385-1-richardw.yang@linux.intel.com> <20190225011534.GA27727@richard> <20190227190402.6c50c8ff@redhat.com> <20190228011325.GA5515@richard> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v5] 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: qemu-devel@nongnu.org, mst@redhat.com On Thu, 28 Feb 2019 09:13:25 +0800 Wei Yang wrote: > On Wed, Feb 27, 2019 at 07:04:02PM +0100, Igor Mammedov wrote: > >On Mon, 25 Feb 2019 09:15:34 +0800 > >Wei Yang wrote: > > > >> On Mon, Feb 25, 2019 at 09:07:08AM +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 should allocate necessary > >> >resources and check if memory-hotplug-support property is enabled. > >> > > >> >At the piix4 and ich9, the memory-hotplug-support property is checked at > >> >plug stage. This means 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). > >> > > >> >Fix it by checking if memory hotplug is enabled at pre_plug stage > >> >where we can gracefully abort hotplug request. > >> > > >> >Signed-off-by: Wei Yang > >> >CC: Igor Mammedov > >> >CC: Eric Blake > >> >Signed-off-by: Wei Yang > >> > > >> >--- > >> >v5: > >> > * rebase on latest upstream > >> > * remove a comment before hotplug_handler_pre_plug > >> > * fix alignment for ich9_pm_device_pre_plug_cb > >> >v4: > >> > * fix code alignment of piix4_device_pre_plug_cb > >> >v3: > >> > * replace acpi_memory_hotplug with memory-hotplug-support in changelog > >> > * fix code alignment of ich9_pm_device_pre_plug_cb > >> > * print which device type memory-hotplug-support is disabled in > >> > ich9_pm_device_pre_plug_cb and piix4_device_pre_plug_cb > >> >v2: > >> > * (imammedo@redhat.com) > >> > - Almost the whole third paragraph > >> > * apply this change to ich9 > >> > * use hotplug_handler_pre_plug() instead of open-coding check > >> >--- > >> > hw/acpi/ich9.c | 15 +++++++++++++-- > >> > hw/acpi/piix4.c | 13 ++++++++++--- > >> > hw/i386/pc.c | 2 ++ > >> > hw/isa/lpc_ich9.c | 1 + > >> > include/hw/acpi/ich9.h | 2 ++ > >> > 5 files changed, 28 insertions(+), 5 deletions(-) > >> > > >> >diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c > >> >index c5d8646abc..e53dfe1ee3 100644 > >> >--- a/hw/acpi/ich9.c > >> >+++ b/hw/acpi/ich9.c > >> >@@ -483,13 +483,24 @@ void ich9_pm_add_properties(Object *obj, ICH9LPCPMRegs *pm, Error **errp) > >> > NULL); > >> > } > >> > > >> >+void ich9_pm_device_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, > >> >+ Error **errp) > >> >+{ > >> >+ ICH9LPCState *lpc = ICH9_LPC_DEVICE(hotplug_dev); > >> >+ > >> >+ if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) && > >> >+ !lpc->pm.acpi_memory_hotplug.is_enabled) > >> >+ error_setg(errp, > >> >+ "memory hotplug is not enabled: %s.memory-hotplug-support " > >> >+ "is not set", object_get_typename(OBJECT(lpc))); > >> >+} > >> >+ > >> > void ich9_pm_device_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, > >> > Error **errp) > >> > { > >> > ICH9LPCState *lpc = ICH9_LPC_DEVICE(hotplug_dev); > >> > > >> >- if (lpc->pm.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 { > >> >diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c > >> >index df8c0db909..8b9654e437 100644 > >> >--- a/hw/acpi/piix4.c > >> >+++ b/hw/acpi/piix4.c > >> >@@ -374,9 +374,16 @@ static void piix4_pm_powerdown_req(Notifier *n, void *opaque) > >> > static void piix4_device_pre_plug_cb(HotplugHandler *hotplug_dev, > >> > DeviceState *dev, Error **errp) > >> > >> Hmm, I found one interesting thing. > >> > >> This function is introduced in > >> > >> commit ec266f408882fd38475f72c4e864ed576228643b > >> pci/pcihp: perform check for bus capability in pre_plug handler > >> > >> This is just implemented in piix4, but don't has the counterpart in ich9. > >> > >> So I suggest to have a follow up patch to create the counterpart for ich9 and > >> then apply this patch on top of that. > >not sure what do you mean, could you be more specific? > > > > Let me reply here. > > Everything starts from device_set_realized(). > > device_set_realized() > hotplug_handler_pre_plug() > dc->realize() > hotplug_handler_plug() > > There is two choice of HotplugHandler : > > * dev's bus hotplug_handler > * machine_hotplug_handler > > Take PIIX as an example, machine_hotplug_handler and pci_bus hotplug_handler > is: > > pc_machine_device_[pre_]plug_cb > piix4_device_[pre_]plug_cb > > if I am correct. > > Now back to your question. > > Commit ec266f408882 introduced piix4_device_pre_plug_cb() to move the check in > pre_plug handler for PIIX. Then I am wondering the counter part of ich9, But I > don't see something for PCI_DEVICE in ich9_pm_device_plug_cb(). So on ich9, > PCI_DEVICE is not pluggable? Maybe I am lost here. > > Or in other words, in case other machine supports PCI_DEVICE hotplug, do we > need to move similar check to pre_plug too? it depends, in case of ICH9. I think acpi hotplug is not used (thankfully) it uses native PCI-E hotplug path. Following pops out when looking for it. hw/pci/pcie.c:void pcie_cap_slot_pre_plug_cb(HotplugHandler *hotplug_dev, DeviceState *dev, hw/pci/pcie_port.c: hc->pre_plug = pcie_cap_slot_pre_plug_cb;