This is a note to let you know that I've just added the patch titled
iommu/amd: Increase interrupt remapping table limit to 512 entries
to the 4.4-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-increase-interrupt-remapping-table-limit-t.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 762d992fe70584120b5913c86a1eee0c3d7222a8
Author: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Date: Thu Oct 15 02:50:02 2020 +0000
iommu/amd: Increase interrupt remapping table limit to 512 entries
[ Upstream commit 73db2fc595f358460ce32bcaa3be1f0cce4a2db1 ]
Certain device drivers allocate IO queues on a per-cpu basis.
On AMD EPYC platform, which can support up-to 256 cpu threads,
this can exceed the current MAX_IRQ_PER_TABLE limit of 256,
and result in the error message:
AMD-Vi: Failed to allocate IRTE
This has been observed with certain NVME devices.
AMD IOMMU hardware can actually support upto 512 interrupt
remapping table entries. Therefore, update the driver to
match the hardware limit.
Please note that this also increases the size of interrupt remapping
table to 8KB per device when using the 128-bit IRTE format.
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>
Link: https://lore.kernel.org/r/20201015025002.87997-1-suravee.suthikulpanit@xxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/amd_iommu_types.h b/drivers/iommu/amd_iommu_types.h
index 695d4e235438c..90832bf00538e 100644
--- a/drivers/iommu/amd_iommu_types.h
+++ b/drivers/iommu/amd_iommu_types.h
@@ -351,7 +351,11 @@ extern bool amd_iommu_np_cache;
/* Only true if all IOMMUs support device IOTLBs */
extern bool amd_iommu_iotlb_sup;
-#define MAX_IRQS_PER_TABLE 256
+/*
+ * AMD IOMMU hardware only support 512 IRTEs despite
+ * the architectural limitation of 2048 entries.
+ */
+#define MAX_IRQS_PER_TABLE 512
#define IRQ_TABLE_ALIGNMENT 128
struct irq_remap_table {
