From: Lu Baolu <baolu.lu@linux.intel.com>
To: Robin Murphy <robin.murphy@arm.com>, joro@8bytes.org
Cc: baolu.lu@linux.intel.com, will@kernel.org, john.garry@huawei.com,
iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] iommu: Update "iommu.strict" documentation
Date: Tue, 15 Jun 2021 15:05:28 +0800 [thread overview]
Message-ID: <a84bb803-1495-bca4-abd3-e5b2654d95ce@linux.intel.com> (raw)
In-Reply-To: <2c8c06e1b449d6b060c5bf9ad3b403cd142f405d.1623682646.git.robin.murphy@arm.com>
On 6/14/21 10:57 PM, Robin Murphy wrote:
> Consolidating the flush queue logic also meant that the "iommu.strict"
> option started taking effect on x86 as well. Make sure we document that.
>
> Fixes: a250c23f15c2 ("iommu: remove DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE")
> Signed-off-by: Robin Murphy <robin.murphy@arm.com>
> ---
> Documentation/admin-guide/kernel-parameters.txt | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index cb89dbdedc46..20a32de990ed 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1987,7 +1987,7 @@
> forcing Dual Address Cycle for PCI cards supporting
> greater than 32-bit addressing.
>
> - iommu.strict= [ARM64] Configure TLB invalidation behaviour
> + iommu.strict= [ARM64, X86] Configure TLB invalidation behaviour
> Format: { "0" | "1" }
> 0 - Lazy mode.
> Request that DMA unmap operations use deferred
> @@ -1998,6 +1998,10 @@
> 1 - Strict mode (default).
> DMA unmap operations invalidate IOMMU hardware TLBs
> synchronously.
> + Note: on x86, the default behaviour depends on the
> + equivalent driver-specific parameters, but a strict
> + mode explicitly specified by either method takes
> + precedence.
>
> iommu.passthrough=
> [ARM64, X86] Configure DMA to bypass the IOMMU by default.
>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Best regards,
baolu
next prev parent reply other threads:[~2021-06-15 7:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 14:57 [PATCH] iommu: Update "iommu.strict" documentation Robin Murphy
2021-06-14 16:29 ` John Garry
2021-06-15 7:05 ` Lu Baolu [this message]
2021-06-17 15:04 ` Joerg Roedel
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