[PATCH kernel v2] PCI: Enable access to custom VPD for Chelsio devices (cxgb3)

[Alexey Kardashevskiy]

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.
The maximum size is taken from EEPROMSIZE in
drivers/net/ethernet/chelsio/cxgb3/common.h. We do not read the tag
as the cxgb3 driver does as the driver supports writing to EEPROM/VPD
and when it writes, it only checks for 8192 bytes boundary. The quirk
is registerted for all devices supported by the cxgb3 driver.

This adds a quirk to the PCI layer (not to the cxgb3 driver) as
the cxgb3 driver itself accesses VPD directly and the problem only exists
with the vfio-pci driver (when cxgb3 is not running on the host and
may not be even loaded) which blocks accesses beyond the first block
of VPD data. However vfio-pci itself does not have quirks mechanism so
we add it to PCI.

Tested on:
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'
	#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'

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 <aik@xxxxxxxxx>
---
Changes:
v2:
* used pci_set_vpd_size() helper
* added explicit list of IDs from cxgb3 driver
* added a note in the commit log why the quirk is not in cxgb3
---
 drivers/pci/quirks.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index 44e0ff3..b22fce5 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -3243,6 +3243,28 @@ 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)
+		return;
+
+	pci_set_vpd_size(dev, max_t(unsigned int, dev->vpd->len, 8192));
+}
+
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x20, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x21, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x22, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x23, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x24, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x25, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x26, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x30, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x31, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x32, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x35, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x36, quirk_chelsio_extend_vpd);
+DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_CHELSIO, 0x37, quirk_chelsio_extend_vpd);
+
 #ifdef CONFIG_ACPI
 /*
  * Apple: Shutdown Cactus Ridge Thunderbolt controller.
-- 
2.5.0.rc3