From: Nishanth Aravamudan Date: Fri, 18 Jan 2013 09:17:36 +0000 (+0000) Subject: pseries/iommu: Ensure TCEs are cleared with non-huge DDW X-Git-Tag: firefly_0821_release~3680^2~1053^2~33 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=71cf1def1ad8384d5fa008f96de94b36668e5460;p=firefly-linux-kernel-4.4.55.git 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. Signed-off-by: Nishanth Aravamudan Signed-off-by: Benjamin Herrenschmidt --- diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c index a55b6858ceac..b4bb9e141149 100644 --- a/arch/powerpc/platforms/pseries/iommu.c +++ b/arch/powerpc/platforms/pseries/iommu.c @@ -1296,6 +1296,7 @@ static int iommu_reconfig_notifier(struct notifier_block *nb, unsigned long acti switch (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- - /* - * Because the notifier runs after isolation of the - * slot, we are guaranteed any DMA window has already - * been revoked and the TCEs have been marked invalid, - * so we don't need a call to remove_ddw(np).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;