Subject: Re: [RFC PATCH kernel] PCI: Enable access to custom VPD for Chelsio devices (cxgb3)

From: Bjorn Helgaas <[email-masked]>
Date: Tue, 6 Sep 2016 10:48:04 -0500

Hi Alexey,

On Thu, Aug 11, 2016 at 08:03:29PM +1000, Alexey Kardashevskiy wrote:
> There is at least one Chelsio 10Gb card which uses VPD area to store
> some custom blocks (example below). However pci_vpd_size() returns
> the length of the first block only assuming that there can be only
> one VPD "End Tag" and VFIO blocks access beyond that offset
> (since 4e1a63555) which leads to the situation when the guest "cxgb3"
> driver fails to probe the device. The host system does not have this
> problem as the drives accesses the config space directly without
> pci_read_vpd()/...
> 
> This adds a quirk to override the VPD size to a bigger value.
> 
> This is the controller:
> Ethernet controller [0200]: Chelsio Communications Inc T310 10GbE Single Port Adapter [1425:0030]
> 
> This is its VPD:
> #0000 Large item 42 bytes; name 0x2 Identifier String
> 	b'10 Gigabit Ethernet-SR PCI Express Adapter'
> #002d Large item 74 bytes; name 0x10
> 	#00 [EC] len=7: b'D76809 '
> 	#0a [FN] len=7: b'46K7897'
> 	#14 [PN] len=7: b'46K7897'
> 	#1e [MN] len=4: b'1037'
> 	#25 [FC] len=4: b'5769'
> 	#2c [SN] len=12: b'YL102035603V'
> 	#3b [NA] len=12: b'00145E992ED1'
> #007a Small item 1 bytes; name 0xf End Tag
> ---
> #0c00 Large item 16 bytes; name 0x2 Identifier String
> 	b'S310E-SR-X      '
> #0c13 Large item 234 bytes; name 0x10
> 	#00 [PN] len=16: b'TBD             '
> 	#13 [EC] len=16: b'110107730D2     '
> 	#26 [SN] len=16: b'97YL102035603V  '
> 	#39 [NA] len=12: b'00145E992ED1'
> 	#48 [V0] len=6: b'175000'
> 	#51 [V1] len=6: b'266666'
> 	#5a [V2] len=6: b'266666'
> 	#63 [V3] len=6: b'2000  '
> 	#6c [V4] len=2: b'1 '
> 	#71 [V5] len=6: b'c2    '
> 	#7a [V6] len=6: b'0     '
> 	#83 [V7] len=2: b'1 '
> 	#88 [V8] len=2: b'0 '
> 	#8d [V9] len=2: b'0 '
> 	#92 [VA] len=2: b'0 '
> 	#97 [RV] len=80: b's\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'...
> #0d00 Large item 252 bytes; name 0x11
> 	#00 [VC] len=16: b'122310_1222 dp  '
> 	#13 [VD] len=16: b'610-0001-00 H1\x00\x00'
> 	#26 [VE] len=16: b'122310_1353 fp  '
> 	#39 [VF] len=16: b'610-0001-00 H1\x00\x00'
> 	#4c [RW] len=173: b'\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00'...
> #0dff Small item 0 bytes; name 0xf End Tag
> 
> Signed-off-by: Alexey Kardashevskiy <[email-masked]>
> ---
>  drivers/pci/quirks.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> index ee72ebe1..94d3fb5 100644
> --- a/drivers/pci/quirks.c
> +++ b/drivers/pci/quirks.c
> @@ -3241,6 +3241,18 @@ DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_CACTUS_RIDGE_4C
>  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_PORT_RIDGE,
>  			quirk_thunderbolt_hotplug_msi);
>  
> +static void quirk_chelsio_extend_vpd(struct pci_dev *dev)
> +{
> +	if (!dev->vpd || !dev->vpd->ops || !dev->vpd->ops->set_size)
> +		return;
> +
> +	dev->vpd->ops->set_size(dev, max_t(unsigned int, dev->vpd->len, 0xe00));
> +}
> +
> +DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO,
> +			PCI_ANY_ID,
> +			quirk_chelsio_extend_vpd);

Do you really want this for *all* Chelsio devices?  If you only need
it for certain devices, the quirk could probably go in the driver.

Can you use pci_set_vpd_size() instead?  There's already a use of that
in cxgb4.

> +
>  #ifdef CONFIG_ACPI
>  /*
>   * Apple: Shutdown Cactus Ridge Thunderbolt controller.
> -- 
> 2.5.0.rc3
> 
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