From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org
Subject: [PATCH] iommu/amd: Increase interrupt remapping table limit to 512 entries
Date: Thu, 15 Oct 2020 02:50:02 +0000 [thread overview]
Message-ID: <20201015025002.87997-1-suravee.suthikulpanit@amd.com> (raw)
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@amd.com>
---
drivers/iommu/amd/amd_iommu_types.h | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/amd/amd_iommu_types.h b/drivers/iommu/amd/amd_iommu_types.h
index 30a5d412255a..427484c45589 100644
--- a/drivers/iommu/amd/amd_iommu_types.h
+++ b/drivers/iommu/amd/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 {
--
2.17.1
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next reply other threads:[~2020-10-15 2:46 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 2:50 Suravee Suthikulpanit [this message]
2020-10-26 2:14 ` [PATCH] iommu/amd: Increase interrupt remapping table limit to 512 entries Suravee Suthikulpanit
2020-11-03 13:21 ` Joerg Roedel
2020-12-01 23:53 ` Jerry Snitselaar
2020-12-07 3:06 ` Suravee Suthikulpanit
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