[PATCHv3,4/4] pci: Blacklist vpd access for buggy devices

From: Babu Moger <babu.moger@oracle.com>

Reading or Writing of PCI VPD data causes system panic.
We saw this problem by running "lspci -vvv" in the beginning.
However this can be easily reproduced by running
 cat /sys/bus/devices/XX../vpd

As even a simple read on any VPD data triggers a system
lockup on certain cards this patch implements a PCI quirk
to disabling VPD acces altogether.
This is done by setting the by setting the vpd length
to '0' initially for those devices, which will then inhibit
access completely..

Cc: Alexander Duyck <alexander.duyck@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Babu Moger <babu.moger@oracle.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/pci/access.c |  4 ++--
 drivers/pci/quirks.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)

On Mon, Feb 15, 2016 at 09:42:02AM +0100, Hannes Reinecke wrote:
> From: Babu Moger <babu.moger@oracle.com>
> 
> Reading or Writing of PCI VPD data causes system panic.
> We saw this problem by running "lspci -vvv" in the beginning.
> However this can be easily reproduced by running
>  cat /sys/bus/devices/XX../vpd
> 
> As even a simple read on any VPD data triggers a system
> lockup on certain cards this patch implements a PCI quirk
> to disabling VPD acces altogether.
> This is done by setting the by setting the vpd length
> to '0' initially for those devices, which will then inhibit
> access completely..

IIRC, Babu was going to open bugzillas with details about the actual
falures.  I'd like references to them here.

> Cc: Alexander Duyck <alexander.duyck@gmail.com>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Signed-off-by: Babu Moger <babu.moger@oracle.com>
> Signed-off-by: Hannes Reinecke <hare@suse.de>
> ---
>  drivers/pci/access.c |  4 ++--
>  drivers/pci/quirks.c | 43 +++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 45 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
> index 253e0c8..8b6f5a2 100644
> --- a/drivers/pci/access.c
> +++ b/drivers/pci/access.c
> @@ -393,7 +393,7 @@ static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
>  	if (pos < 0)
>  		return -EINVAL;
>  
> -	if (!vpd->valid) {
> +	if (!vpd->valid && vpd->base.len > 0) {
>  		vpd->valid = true;
>  		vpd->base.len = pci_vpd_pci22_size(dev, vpd->base.len);
>  	}
> @@ -459,7 +459,7 @@ static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count
>  	if (pos < 0 || (pos & 3) || (count & 3))
>  		return -EINVAL;
>  
> -	if (!vpd->valid) {
> +	if (!vpd->valid && vpd->base.len > 0) {

I think these changes to pci_vpd_pci22_read() and
pci_vpd_pci22_write() are unnecessary because pci_vpd_pci22_size()
already returns 0 when you pass 0 to it.

>  		vpd->valid = true;
>  		vpd->base.len = pci_vpd_pci22_size(dev, vpd->base.len);
>  	}
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index 0575a1e..df1178f 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -2135,6 +2135,49 @@ static void quirk_via_cx700_pci_parking_caching(struct pci_dev *dev)
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_VIA, 0x324e, quirk_via_cx700_pci_parking_caching);
>  
>  /*
> + * A read/write to sysfs entry ('/sys/bus/pci/devices/<id>/vpd')
> + * will dump 32k of data. The default length is set as 32768.
> + * Reading a full 32k will cause an access beyond the VPD end tag.
> + * The system behaviour at that point is mostly unpredictable.
> + * Apparently, some vendors have not implemented this VPD headers properly.
> + * Adding a generic function disable vpd data for these buggy adapters
> + * Add the DECLARE_PCI_FIXUP_FINAL line below with the specific with
> + * vendor and device of interest to use this quirk.
> + */
> +static void quirk_blacklist_vpd(struct pci_dev *dev)
> +{
> +	if (dev->vpd) {
> +		dev->vpd->len = 0;
> +		dev_warn(&dev->dev, "PCI vpd access has been disabled due to firmware bug\n");
> +	}
> +}
> +
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0060,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x007c,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0413,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0078,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0079,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0073,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x0071,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005b,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x002f,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005d,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_LSI_LOGIC, 0x005f,
> +		quirk_blacklist_vpd);
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATTANSIC, PCI_ANY_ID,
> +		quirk_blacklist_vpd);
> +
> +/*
>   * For Broadcom 5706, 5708, 5709 rev. A nics, any read beyond the
>   * VPD end tag will hang the device.  This problem was initially
>   * observed when a vpd entry was created in sysfs
> -- 
> 1.8.5.6
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-pci" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html