RE: [PATCH 2/2] pci: Update VPD size with correct length

[<Jordan_Hargrave@Dell.com>]

>On Mon, Dec 28, 2015 at 9:29 PM,  <Jordan_Hargrave@dell.com> wrote:
>> I had posted a patch recently to enable exposing the VPD-R valyes to sysfs.  I need access
>> to these to parse into systemd for network naming (biosdevname style names).
>>
>>
>> The VPD-R is a readonly area contained within the PCI Vital Product
>> data.  There are some standard and vendor-specific keys stored in
>> this region.
>>
>> PN = Part Number
>> SN = Serial Number
>> MN = Manufacturer ID
>> Vx = Vendor-specific (x=0..9 A..Z)
>>
>> Biosdevname/Systemd will use these VPD keys for determining Network
>> partitioning and port numbers for NIC cards
>
>Can you please repost this as a patch instead of as a reply to our
>thread about VPD size.  The fact is the subject is misleading as your
>patch isn't actually related to VPD sizing.
>

I had already posted this a few weeks back but never got any feedback.

[PATCH] Create sysfs entries for VPD-R keys
https://marc.info/?l=linux-pci&m=144959803316031&w=2

>> Signed-off-by: Jordan Hargrave <Jordan_Hargrave@dell.com>
>> ---
>>  drivers/pci/pci-sysfs.c |  216 +++++++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/pci.h     |    2 +
>>  2 files changed, 218 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
>> index eead54c..4966ece 100644
>> --- a/drivers/pci/pci-sysfs.c
>> +++ b/drivers/pci/pci-sysfs.c
>> @@ -1295,6 +1295,210 @@ static struct bin_attribute pcie_config_attr = {
>>         .write = pci_write_config,
>>  };
>>
>> +static umode_t vpd_attr_exist(struct kobject *kobj,
>> +                             struct attribute *attr, int n)
>> +{
>> +       struct device *dev;
>> +       struct pci_dev *pdev;
>> +       const char *name;
>> +       int i;
>> +
>> +       dev = container_of(kobj, struct device, kobj);
>> +       pdev = to_pci_dev(dev);
>> +
>> +       name = attr->name;
>> +       if (pdev->vpdr_data == NULL)
>> +               return 0;
>> +       i = pci_vpd_find_info_keyword(pdev->vpdr_data, 0,
>> +                                     pdev->vpdr_len, name);
>> +       return (i >= 0 ? S_IRUGO : 0);
>> +}
>> +
>
>So I assume there is another patch that implements
>pci_vpd_find_info_keyword so that it can go through the vpdr_data and
>parse it?
>

That's already an existing function in drivers/pci/vpd.c

>> +static ssize_t vpd_attr_show(struct device *dev,
>> +                            struct device_attribute *attr, char *buf)
>> +{
>> +       struct pci_dev *pdev;
>> +       const char *name;
>> +       char kv_data[257] = { 0 };
>> +       int i, len;
>> +
>> +       pdev = to_pci_dev(dev);
>> +       name = attr->attr.name;
>> +       if (pdev->vpdr_data == NULL)
>> +               return 0;
>> +       i = pci_vpd_find_info_keyword(pdev->vpdr_data, 0,
>> +                                     pdev->vpdr_len, name);
>> +       if (i >= 0) {
>> +               len = pci_vpd_info_field_size(&pdev->vpdr_data[i]);
>> +               memcpy(kv_data, pdev->vpdr_data + i +
>> +                      PCI_VPD_INFO_FLD_HDR_SIZE, len);
>> +               return scnprintf(buf, PAGE_SIZE, "%s\n", kv_data);
>> +       }
>> +       return 0;
>> +}
>> +
>> +#define VPD_ATTR_RO(x) \
>> +struct device_attribute vpd ## x = { \
>> +       .attr = { .name = #x, .mode = S_IRUGO | S_IWUSR }, \
>> +       .show = vpd_attr_show \
>> +}
>> +
>> +VPD_ATTR_RO(PN);
>> +VPD_ATTR_RO(EC);
>> +VPD_ATTR_RO(MN);
>> +VPD_ATTR_RO(SN);
>> +VPD_ATTR_RO(V0);
>> +VPD_ATTR_RO(V1);
>> +VPD_ATTR_RO(V2);
>> +VPD_ATTR_RO(V3);
>> +VPD_ATTR_RO(V4);
>> +VPD_ATTR_RO(V5);
>> +VPD_ATTR_RO(V6);
>> +VPD_ATTR_RO(V7);
>> +VPD_ATTR_RO(V8);
>> +VPD_ATTR_RO(V9);
>> +VPD_ATTR_RO(VA);
>> +VPD_ATTR_RO(VB);
>> +VPD_ATTR_RO(VC);
>> +VPD_ATTR_RO(VD);
>> +VPD_ATTR_RO(VE);
>> +VPD_ATTR_RO(VF);
>> +VPD_ATTR_RO(VG);
>> +VPD_ATTR_RO(VH);
>> +VPD_ATTR_RO(VI);
>> +VPD_ATTR_RO(VJ);
>> +VPD_ATTR_RO(VK);
>> +VPD_ATTR_RO(VL);
>> +VPD_ATTR_RO(VM);
>> +VPD_ATTR_RO(VN);
>> +VPD_ATTR_RO(VO);
>> +VPD_ATTR_RO(VP);
>> +VPD_ATTR_RO(VQ);
>> +VPD_ATTR_RO(VR);
>> +VPD_ATTR_RO(VS);
>> +VPD_ATTR_RO(VT);
>> +VPD_ATTR_RO(VU);
>> +VPD_ATTR_RO(VV);
>> +VPD_ATTR_RO(VW);
>> +VPD_ATTR_RO(VX);
>> +VPD_ATTR_RO(VY);
>> +VPD_ATTR_RO(VZ);
>> +
>> +static struct attribute *vpd_attributes[] = {
>> +       &vpdPN.attr,
>> +       &vpdEC.attr,
>> +       &vpdMN.attr,
>> +       &vpdSN.attr,
>> +       &vpdV0.attr,
>> +       &vpdV1.attr,
>> +       &vpdV2.attr,
>> +       &vpdV3.attr,
>> +       &vpdV4.attr,
>> +       &vpdV5.attr,
>> +       &vpdV6.attr,
>> +       &vpdV7.attr,
>> +       &vpdV8.attr,
>> +       &vpdV9.attr,
>> +       &vpdVA.attr,
>> +       &vpdVB.attr,
>> +       &vpdVC.attr,
>> +       &vpdVD.attr,
>> +       &vpdVE.attr,
>> +       &vpdVF.attr,
>> +       &vpdVG.attr,
>> +       &vpdVH.attr,
>> +       &vpdVI.attr,
>> +       &vpdVJ.attr,
>> +       &vpdVK.attr,
>> +       &vpdVL.attr,
>> +       &vpdVM.attr,
>> +       &vpdVN.attr,
>> +       &vpdVO.attr,
>> +       &vpdVP.attr,
>> +       &vpdVQ.attr,
>> +       &vpdVR.attr,
>> +       &vpdVS.attr,
>> +       &vpdVT.attr,
>> +       &vpdVU.attr,
>> +       &vpdVV.attr,
>> +       &vpdVW.attr,
>> +       &vpdVX.attr,
>> +       &vpdVY.attr,
>> +       &vpdVZ.attr,
>> +       NULL,
>> +};
>> +
>> +static struct attribute_group vpd_attr_group = {
>> +       .name = "vpdr",
>> +       .attrs = vpd_attributes,
>> +       .is_visible = vpd_attr_exist,
>> +};
>> +
>> +
>> +static int pci_get_vpd_tag(struct pci_dev *dev, int off, int *len)
>> +{
>> +       u8  tag[3];
>> +       int rc, tlen;
>> +
>> +       *len = 0;
>> +       /* Quirk Atheros cards, reading VPD hangs system for 20s */
>> +       if (dev->vendor == PCI_VENDOR_ID_ATHEROS ||
>> +           dev->vendor == PCI_VENDOR_ID_ATTANSIC)
>> +               return -ENOENT;
>
>I'm not really sure this is the right place for this type of quirk.
>If this is really an issue maybe we should just disable VPD for these
>devices.  Otherwise there isn't anything to stop someone from going in
>and reading the VPD region via the existing VPD interfaces.
>

This could be moved elsewhere. There's a similar quirk for megaraid cards that was posted recently.
[PATCH v4] pci: Limit VPD length for megaraid_sas adapter

>> +       rc = pci_read_vpd(dev, off, 1, tag);
>> +       if (rc != 1)
>> +               return -ENOENT;
>> +       if (tag[0] == 0x00 || tag[0] == 0xFF || tag[0] == 0x7F)
>> +               return -ENOENT;
>> +       if (tag[0] & PCI_VPD_LRDT) {
>> +               rc = pci_read_vpd(dev, off+1, 2, tag+1);
>> +               if (rc != 2)
>> +                       return -ENOENT;
>> +               tlen = pci_vpd_lrdt_size(tag) +
>> +                       PCI_VPD_LRDT_TAG_SIZE;
>> +       } else {
>> +               tlen = pci_vpd_srdt_size(tag) +
>> +                       PCI_VPD_SRDT_TAG_SIZE;
>> +               tag[0] &= ~PCI_VPD_SRDT_LEN_MASK;
>> +       }
>> +       /* Verify VPD tag fits in area */
>> +       if (tlen + off > dev->vpd->len)
>> +               return -ENOENT;
>> +       *len = tlen;
>> +       return tag[0];
>> +}
>> +
>> +static int pci_load_vpdr(struct pci_dev *dev)
>> +{
>> +       int rlen, ilen, tag, rc;
>> +
>> +       /* Check for VPD-I and VPD-R tag */
>> +       tag = pci_get_vpd_tag(dev, 0, &ilen);
>> +       if (tag != PCI_VPD_LRDT_ID_STRING)
>> +               return -ENOENT;
>> +       tag = pci_get_vpd_tag(dev, ilen, &rlen);
>> +       if (tag != PCI_VPD_LRDT_RO_DATA)
>> +               return -ENOENT;
>> +
>> +       rlen -= PCI_VPD_LRDT_TAG_SIZE;
>> +       dev->vpdr_len = rlen;
>> +       dev->vpdr_data = kzalloc(rlen, GFP_ATOMIC);
>> +       if (dev->vpdr_data == NULL)
>> +               return -ENOMEM;
>> +
>
>Why not cache the ID string as well?  Seems like it might be a field
>people would want to read on a regular basis in order to find out what
>is there.
>
I could add that. What should attribute be called, 'vpdinfo', 'vpdi', etc?

>> +       rc = pci_read_vpd(dev, ilen + PCI_VPD_LRDT_TAG_SIZE,
>> +                         rlen, dev->vpdr_data);
>> +       if (rc != rlen)
>> +               goto error;
>> +       if (sysfs_create_group(&dev->dev.kobj, &vpd_attr_group))
>> +               goto error;
>> +       return 0;
>> + error:
>> +       kfree(dev->vpdr_data);
>> +       dev->vpdr_len = 0;
>> +       return -ENOENT;
>> +}
>> +
>
>This bit here needs to reset vpdr_data back to NULL.  Otherwise you
>could cause memory corruption via a double free in your two clean-up
>routines called out below.

Ok will fix that.