Re: [PATCH] irq: add quirk for broken interrupt remapping on 55XX chipsets

[Jiang Liu <liuj97@gmail.com>]

On 03/02/2013 02:20 AM, Yinghai Lu wrote:
> On Fri, Mar 1, 2013 at 9:17 AM, Neil Horman <nhorman@tuxdriver.com> wrote:
>> A few years back intel published a spec update:
>> http://www.intel.com/content/dam/doc/specification-update/5520-and-5500-chipset-ioh-specification-update.pdf
>>
>> For the 5520 and 5500 chipsets which contained an errata (specificially errata
>> 53), which noted that these chipsets can't properly do interrupt remapping, and
>> as a result the recommend that interrupt remapping be disabled in bios.  While
>> many vendors have a bios update to do exactly that, not all do, and of course
>> not all users update their bios to a level that corrects the problem.  As a
>> result, occasionally interrupts can arrive at a cpu even after affinity for that
>> interrupt has be moved, leading to lost or spurrious interrupts (usually
>> characterized by the message:
>> kernel: do_IRQ: 7.71 No irq handler for vector (irq -1)
>>
>> There have been several incidents recently of people seeing this error, and
>> investigation has shown that they have system for which their BIOS level is such
>> that this feature was not properly turned off.  As such, it would be good to
>> give them a reminder that their systems are vulnurable to this problem.
>>
>> Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
>> CC: Prarit Bhargava <prarit@redhat.com>
>> CC: Don Zickus <dzickus@redhat.com>
>> CC: Don Dutile <ddutile@redhat.com>
>> CC: Bjorn Helgaas <bhelgaas@google.com>
>> CC: Asit Mallick <asit.k.mallick@intel.com>
>> CC: linux-pci@vger.kernel.org
>> ---
>>  drivers/iommu/intel_irq_remapping.c | 20 ++++++++++++++++++++
>>  include/linux/pci_ids.h             |  2 ++
>>  2 files changed, 22 insertions(+)
>>
>> diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
>> index f3b8f23..9bfb6c2 100644
>> --- a/drivers/iommu/intel_irq_remapping.c
>> +++ b/drivers/iommu/intel_irq_remapping.c
>> @@ -1113,3 +1113,23 @@ struct irq_remap_ops intel_irq_remap_ops = {
>>         .msi_setup_irq          = intel_msi_setup_irq,
>>         .setup_hpet_msi         = intel_setup_hpet_msi,
>>  };
>> +
>> +
>> +static void intel_remapping_check(struct pci_dev *dev)
>> +{
>> +       u8 revision;
>> +
>> +       pci_read_config_byte(dev, PCI_REVISION_ID, &revision);
>> +
>> +       if ((revision == 0x13) && irq_remapping_enabled) {
>> +               pr_warn("WARNING WARNING WARNING WARNING WARNING WARNING\n"
>> +                       "This system BIOS has enabled interrupt remapping\n"
>> +                       "on a chipset that contains an errata making that\n"
>> +                       "feature unstable.  Please reboot with nointremap\n"
>> +                       "added to the kernel command line and contact\n"
>> +                       "your BIOS vendor for an update");
>> +       }
>> +}
>> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5520_IOHUB, intel_remapping_check);
>> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_5500_IOHUB, intel_remapping_check);
> 
> only for x86 platform?
> If so, you can check that in arch/x86/kernel/early-quirks.c::early_quirks()
> and set one flag and later print warning and skip there if someone
> need to enable intr-remap.
> So users will not need to reboot the system...
We have just struggled with this issue when doing kvm restarting stress tests,
and finally found it's a chipset errata. Thanks for fix it.
And I think 5520/5500 is for x86 only, so could move it to x86 arch subdirectory.

Regards!
Gerry

> 
> Thanks
> 
> Yinghai
> 
>> +
>> diff --git a/include/linux/pci_ids.h b/include/linux/pci_ids.h
>> index 31717bd..54027a6 100644
>> --- a/include/linux/pci_ids.h
>> +++ b/include/linux/pci_ids.h
>> @@ -2732,6 +2732,8 @@
>>  #define PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_RANK_REV2  0x2db2
>>  #define PCI_DEVICE_ID_INTEL_LYNNFIELD_MC_CH2_TC_REV2    0x2db3
>>  #define PCI_DEVICE_ID_INTEL_82855PM_HB 0x3340
>> +#define PCI_DEVICE_ID_INTEL_5500_IOHUB 0x3403
>> +#define PCI_DEVICE_ID_INTEL_5520_IOHUB 0x3406
>>  #define PCI_DEVICE_ID_INTEL_IOAT_TBG4  0x3429
>>  #define PCI_DEVICE_ID_INTEL_IOAT_TBG5  0x342a
>>  #define PCI_DEVICE_ID_INTEL_IOAT_TBG6  0x342b
>> --
>> 1.7.11.7
>>
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