From: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
To: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org
Cc: joro@8bytes.org
Subject: Re: [PATCH] iommu/amd: Increase interrupt remapping table limit to 512 entries
Date: Mon, 26 Oct 2020 09:14:21 +0700 [thread overview]
Message-ID: <ccbe0d64-39b5-4c09-5aae-6351fd1f6db4@amd.com> (raw)
In-Reply-To: <20201015025002.87997-1-suravee.suthikulpanit@amd.com>
Hi Joerg,
Do you have any concerns regarding this patch?
Thanks,
Suravee
On 10/15/20 9:50 AM, Suravee Suthikulpanit wrote:
> 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 {
>
next prev parent reply other threads:[~2020-10-26 2:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-15 2:50 [PATCH] iommu/amd: Increase interrupt remapping table limit to 512 entries Suravee Suthikulpanit
2020-10-26 2:14 ` Suravee Suthikulpanit [this message]
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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