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 5.4-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-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 51804898bd190b1c72d8c90caf5387ee93bf245d 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 0679896b9e2e1..3ec090adcdae7 100644 --- a/drivers/iommu/amd_iommu_types.h +++ b/drivers/iommu/amd_iommu_types.h @@ -406,7 +406,11 @@ 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 {