From 4528752f49c1f4025473d12bc5fa9181085c3f22 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Wed, 2 Dec 2009 15:05:56 -0800 Subject: [PATCH] x86, Calgary IOMMU quirk: Find nearest matching Calgary while walking up the PCI tree On a multi-node x3950M2 system, there's a slight oddity in the PCI device tree for all secondary nodes: 30:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1) \-33:00.0 PCI bridge: IBM CalIOC2 PCI-E Root Port (rev 01) \-34:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 1078 (rev 04) ...as compared to the primary node: 00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev e1) \-01:00.0 VGA compatible controller: ATI Technologies Inc ES1000 (rev 02) 03:00.0 PCI bridge: IBM CalIOC2 PCI-E Root Port (rev 01) \-04:00.0 RAID bus controller: LSI Logic / Symbios Logic MegaRAID SAS 1078 (rev 04) In both nodes, the LSI RAID controller hangs off a CalIOC2 device, but on the secondary nodes, the BIOS hides the VGA device and substitutes the device tree ending with the disk controller. It would seem that Calgary devices don't necessarily appear at the top of the PCI tree, which means that the current code to find the Calgary IOMMU that goes with a particular device is buggy. Rather than walk all the way to the top of the PCI device tree and try to match bus number with Calgary descriptor, the code needs to examine each parent of the particular device; if it encounters a Calgary with a matching bus number, simply use that. Otherwise, we BUG() when the bus number of the Calgary doesn't match the bus number of whatever's at the top of the device tree. Extra note: This patch appears to work correctly for the x3950 that came before the x3950 M2. Signed-off-by: Darrick J. Wong Acked-by: Muli Ben-Yehuda Cc: FUJITA Tomonori Cc: Joerg Roedel Cc: Yinghai Lu Cc: Jon D. Mason Cc: Corinna Schultz Cc: LKML-Reference: <20091202230556.GG10295@tux1.beaverton.ibm.com> Signed-off-by: Ingo Molnar --- arch/x86/kernel/pci-calgary_64.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c index 849a0995d970..c563e4c8ff39 100644 --- a/arch/x86/kernel/pci-calgary_64.c +++ b/arch/x86/kernel/pci-calgary_64.c @@ -316,13 +316,15 @@ static inline struct iommu_table *find_iommu_table(struct device *dev) pdev = to_pci_dev(dev); + /* search up the device tree for an iommu */ pbus = pdev->bus; - - /* is the device behind a bridge? Look for the root bus */ - while (pbus->parent) + do { + tbl = pci_iommu(pbus); + if (tbl && tbl->it_busno == pbus->number) + break; + tbl = NULL; pbus = pbus->parent; - - tbl = pci_iommu(pbus); + } while (pbus); BUG_ON(tbl && (tbl->it_busno != pbus->number)); -- 2.30.2