Messages in this thread | | | Date | Wed, 2 Dec 2009 17:51:19 -0600 | Subject | Re: [PATCH] Calgary: Find nearest matching Calgary while walking up the PCI tree | From | Jon Mason <> |
| |
On Tue, Dec 1, 2009 at 7:47 PM, Darrick J. Wong <djwong@us.ibm.com> wrote: > 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. > > Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> > --- > > arch/x86/kernel/pci-calgary_64.c | 12 +++++++----- > 1 files changed, 7 insertions(+), 5 deletions(-) > > > diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c > index 971a3be..e6ec8a2 100644 > --- a/arch/x86/kernel/pci-calgary_64.c > +++ b/arch/x86/kernel/pci-calgary_64.c > @@ -318,13 +318,15 @@ 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;
I believe the NULL assignment is unnecessary. If not, then the if check and BUG_ON are busted.
> pbus = pbus->parent; > - > - tbl = pci_iommu(pbus); > + } while (pbus); > > BUG_ON(tbl && (tbl->it_busno != pbus->number)); > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |