This is a note to let you know that I've just added the patch titled
iommu/amd: Fix unity mapping initialization race
to the 4.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-amd-fix-unity-mapping-initialization-race.patch
and it can be found in the queue-4.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 522e5cb76d0663c88f96b6a8301451c8efa37207 Mon Sep 17 00:00:00 2001
From: Joerg Roedel <jroedel@xxxxxxx>
Date: Fri, 1 Jul 2016 16:42:55 +0200
Subject: iommu/amd: Fix unity mapping initialization race
From: Joerg Roedel <jroedel@xxxxxxx>
commit 522e5cb76d0663c88f96b6a8301451c8efa37207 upstream.
There is a race condition in the AMD IOMMU init code that
causes requested unity mappings to be blocked by the IOMMU
for a short period of time. This results on boot failures
and IO_PAGE_FAULTs on some machines.
Fix this by making sure the unity mappings are installed
before all other DMA is blocked.
Fixes: aafd8ba0ca74 ('iommu/amd: Implement add_device and remove_device')
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/iommu/amd_iommu_init.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1363,13 +1363,23 @@ static int __init amd_iommu_init_pci(voi
break;
}
+ /*
+ * Order is important here to make sure any unity map requirements are
+ * fulfilled. The unity mappings are created and written to the device
+ * table during the amd_iommu_init_api() call.
+ *
+ * After that we call init_device_table_dma() to make sure any
+ * uninitialized DTE will block DMA, and in the end we flush the caches
+ * of all IOMMUs to make sure the changes to the device table are
+ * active.
+ */
+ ret = amd_iommu_init_api();
+
init_device_table_dma();
for_each_iommu(iommu)
iommu_flush_all_caches(iommu);
- ret = amd_iommu_init_api();
-
if (!ret)
print_iommu_info();
Patches currently in stable-queue which might be from jroedel@xxxxxxx are
queue-4.6/iommu-vt-d-enable-qi-on-all-iommus-before-setting-root-entry.patch
queue-4.6/iommu-amd-fix-unity-mapping-initialization-race.patch
queue-4.6/iommu-arm-smmu-wire-up-map_sg-for-arm-smmu-v3.patch
queue-4.6/iommu-rockchip-fix-zap-cache-during-device-attach.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html