[PATCH 7/7] PCI: use pf as dma_dev for vf that does not have func0 sibling

From: Yinghai Lu
Date: Mon May 13 2013 - 22:29:37 EST


Fix crash:
[ 122.181002] pci 0000:c4:00.4: [10df:e228] type 00 class 0x020000
[ 122.188541] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
[ 122.197324] IP: [<ffffffff81f58f78>] intel_iommu_add_device+0x108/0x1e0
[ 122.204753] PGD 0
[ 122.207019] Oops: 0000 [#1] SMP
[ 122.210655] Modules linked in:
[ 122.214084] CPU: 49 PID: 1 Comm: swapper/0 Tainted: G I 3.9.0-yh-09240-g8a69c01-dirty #1571
...
[ 122.365363] Call Trace:
[ 122.368112] [<ffffffff81f4ee2e>] iommu_bus_notifier+0x3e/0xd0
[ 122.374645] [<ffffffff820b702e>] notifier_call_chain+0x6e/0xb0
[ 122.381277] [<ffffffff810b912e>] __blocking_notifier_call_chain+0x5e/0x90
[ 122.388963] [<ffffffff810b9176>] blocking_notifier_call_chain+0x16/0x20
[ 122.396471] [<ffffffff81762fc5>] device_add+0x475/0x6f0

pv is c3:00.0, and vf is from c4:00.4 and there is no c4:00.0,
as we have
Initial VFs: 64, Total VFs: 64, Number of VFs: 63, Function Dependency Link: 00
VF offset: 260, stride: 1

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx

---
drivers/iommu/intel-iommu.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

Index: linux-2.6/drivers/iommu/intel-iommu.c
===================================================================
--- linux-2.6.orig/drivers/iommu/intel-iommu.c
+++ linux-2.6/drivers/iommu/intel-iommu.c
@@ -4185,11 +4185,15 @@ static int intel_iommu_add_device(struct
* required ACS flags, add to the same group as function 0.
*/
if (dma_pdev->multifunction &&
- !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS))
- swap_pci_ref(&dma_pdev,
- pci_get_slot(dma_pdev->bus,
+ !pci_acs_enabled(dma_pdev, REQ_ACS_FLAGS)) {
+ struct pci_dev *dev_tmp = pci_get_slot(dma_pdev->bus,
PCI_DEVFN(PCI_SLOT(dma_pdev->devfn),
- 0)));
+ 0));
+
+ if (!dev_tmp && dma_pdev->is_virtfn)
+ dev_tmp = pci_dev_get(dma_pdev->physfn);
+ swap_pci_ref(&dma_pdev, dev_tmp);
+ }

/*
* Devices on the root bus go through the iommu. If that's not us,
--
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