pseries/iommu: ensure TCEs are cleared with non-huge DDW
PATCH 1/1 pseries/iommu: ensure TCEs are cleared with non-huge DDW
There are now two kinds of DMA windows that might be presented by PowerVM DDW support -- huge windows (that can map all of system memory regardless of the LPAR configuration) and non-huge windows (which can't). They are implemented slightly differently in PowerVM, and thus have different characteristics. The most obvious is that slot isolate doesn't clear the TCEs/window for us with non-huge windows. Thus, when a DLPAR operation occurs on a slot using a non-huge window, TCEs are still present (the notifier chain doesn't currently remove them explicitly) and the DLPAR fails. Fix this by calling remove_ddw() first, which will unmap the DDW TCEs.
Note: a corresponding change to drmgr is needed to actually successfully DLPAR, such that the device-tree update (which causes the notifier chain to fire) occurs before slot isolate.
arch/powerpc/platforms/pseries/iommu.c +1 -10
@@ -1296,6 +1296,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long actiswitch (action) {case OF_RECONFIG_DETACH_NODE : +remove_ddw (np);if (pci && pci->iommu_table)iommu_free_table (pci->iommu_table, np->full_name);
@@ -1308,16 +1309,6 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti } }spin_unlock (&direct_window_list_lock); - -/* -* Because the notifier runs after isolation of the -* slot, we are guaranteed any DMA window has already -* been revoked and the TCEs have been marked invalid, -* so we don't need a call to remove_ddw(np). However, -* if an additional notifier action is added before the -* isolate call, we should update this code for -* completeness with such a call. -*/ break ;default : err =NOTIFY_DONE ;