linux-kernel - Re: [PATCHv2 4/4] pci: Blacklist vpd access for buggy devices

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Date:	Tue, 9 Feb 2016 15:24:10 -0600
From:	Babu Moger <babu.moger@...cle.com>
To:	Bjorn Helgaas <helgaas@...nel.org>, Hannes Reinecke <hare@...e.de>
Cc:	Alexander Duyck <alexander.duyck@...il.com>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCHv2 4/4] pci: Blacklist vpd access for buggy devices

On 2/9/2016 3:07 PM, Bjorn Helgaas wrote:
> There seem to be several revs of this patch, and it's hard for me to
> keep track of what's current.  If you want to update any patch in the
> series, please repost the entire series with a new version number.

 Here is the latest of patch 4/4.
 https://patchwork.kernel.org/patch/8084221/

 I will wait for Hannes's response before re-posting it.
 Hannes, If you want me to re-post all the series let me know.
 
> 
> On Wed, Jan 13, 2016 at 12:25:35PM +0100, Hannes Reinecke wrote:
>> From: Babu Moger <babu.moger@...cle.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 by setting the vpd length
> 
> s/acces/access/
> s/vpd/VPD/
> 
>> to '0'.
>>
>> Signed-off-by: Babu Moger <babu.moger@...cle.com>
>> Signed-off-by: Hannes Reinecke <hare@...e.de>
>> ---
>>  drivers/pci/access.c |  5 ++++-
>>  drivers/pci/quirks.c | 41 +++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 45 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pci/access.c b/drivers/pci/access.c
>> index 914e023..82f41a8 100644
>> --- a/drivers/pci/access.c
>> +++ b/drivers/pci/access.c
>> @@ -396,7 +396,7 @@ 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);
>>  	}
>> @@ -459,6 +459,9 @@ static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count
>>  	loff_t end = pos + count;
>>  	int ret = 0;
>>  
>> +	if (vpd->base.len == 0)
>> +		return -EIO;
>> +
>>  	if (!vpd->valid)
>>  		return -EAGAIN;
>>  
>> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
>> index 7e32730..af0f8a1 100644
>> --- a/drivers/pci/quirks.c
>> +++ b/drivers/pci/quirks.c
>> @@ -2123,6 +2123,47 @@ 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");
> 
> "PCI" is superfluous and "VPD" should be capitalized.
> 
>> +	}
>> +}
>> +
>> +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);
>> +
>> +/*
>>   * 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
>>
>> --
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