Re: [PATCH v4] irq: add quirk for broken interrupt remapping on 55XX chipsets

[Yinghai Lu]

On Thu, Apr 4, 2013 at 8:08 AM, Neil Horman <nhorman@xxxxxxxxxxxxx> 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@xxxxxxxxxxxxx>
> CC: Prarit Bhargava <prarit@xxxxxxxxxx>
> CC: Don Zickus <dzickus@xxxxxxxxxx>
> CC: Don Dutile <ddutile@xxxxxxxxxx>
> CC: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> CC: Asit Mallick <asit.k.mallick@xxxxxxxxx>
> CC: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> CC: linux-pci@xxxxxxxxxxxxxxx
> ---
>
> Change notes:
>
> v2)
>
> * Moved the quirk to the x86 arch, since consensus seems to be that the 55XX
> chipset series is x86 only.  I decided however to keep the quirk as a regular
> quirk, not an early_quirk.  Early quirks have no way currently to determine if
> BIOS has properly disabled the feature in the iommu, at least not without
> significant hacking, and since its quite possible this will be a short lived
> quirk, should Don Z's workaround code prove successful (and it looks like it may
> well), I don't think that necessecary.
>
> * Removed the WARNING banner from the quirk, and added the HW_ERR token to the
> string, I opted to leave the newlines in place however, as I really couldnt
> find a way to keep the text on a single line is still legible from a code
> perspective.  I think theres enough language in there that using cscope on just
> about any substring however will turn it up, and again, this may be a short
> lived quirk.
>
> v3)
>
> * Removed defines from pci_ids.h, and used direct id values as per request from
> Bjorn.
>
> v4)
>
> * Converted pr_warn to WARN_TAINT(TAINT_FIRMWARE_WORKAROUND) as per David
> Woodhouse
> ---
>  arch/x86/kernel/quirks.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/arch/x86/kernel/quirks.c b/arch/x86/kernel/quirks.c
> index 26ee48a..eb0785d 100644
> --- a/arch/x86/kernel/quirks.c
> +++ b/arch/x86/kernel/quirks.c
> @@ -5,6 +5,7 @@
>  #include <linux/irq.h>
>
>  #include <asm/hpet.h>
> +#include "../../../drivers/iommu/irq_remapping.h"
>
>  #if defined(CONFIG_X86_IO_APIC) && defined(CONFIG_SMP) && defined(CONFIG_PCI)
>
> @@ -567,3 +568,20 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F5,
>                         quirk_amd_nb_node);
>
>  #endif
> +
> +static void intel_remapping_check(struct pci_dev *dev)
> +{
> +       u8 revision;
> +
> +       pci_read_config_byte(dev, PCI_REVISION_ID, &revision);
> +
> +       WARN_TAINT(((revision == 0x13) && irq_remapping_enabled),
> +                  TAINT_FIRMWARE_WORKAROUND,
> +                   "This system BIOS has enabled interrupt remapping\n"
> +                   "on a chipset that contains an erratum 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, 0x3406, intel_remapping_check);
> +DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_INTEL, 0x3403, intel_remapping_check);

No, you only address my one request, move to arch/x86 directory.

You need to move the quirk to early_quirk to append nointremap to
avoid extra rebooting.

Thanks

Yinghai
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