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From: John Garry <john.garry@huawei.com>
To: Robin Murphy <robin.murphy@arm.com>, <joro@8bytes.org>,
	<will@kernel.org>
Cc: <iommu@lists.linux-foundation.org>,
	<linux-kernel@vger.kernel.org>, <hch@lst.de>
Subject: Re: [PATCH] iommu: Print default strict or lazy mode at init time
Date: Tue, 1 Jun 2021 16:50:39 +0100	[thread overview]
Message-ID: <e478aea8-54d3-bfc6-1bc8-b0c7709e353a@huawei.com> (raw)
In-Reply-To: <3ee986a0-29c1-100c-c72f-360f919caf7d@arm.com>

On 01/06/2021 10:09, Robin Murphy wrote:
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 808ab70d5df5..f25fae62f077 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -138,6 +138,11 @@ static int __init iommu_subsys_init(void)
>>           (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
>>               "(set via kernel command line)" : "");
>> +    pr_info("Default DMA domain mode: %s %s\n",
> 
> Nit: I think this might be a little unclear for end-users - *I'm* not 
> even sure whether "Default" here is meant to refer to the mode setting 
> itself or to default domains (of DMA type). Maybe something like "DMA 
> domain TLB invalidation policy"? Certainly it seems like a good idea to 
> explicitly mention invalidation to correlate with the documentation of 
> the "iommu.strict" parameter.
> 
> Ack to the general idea though.

ok, so I'll go with this:

pr_info("DMA domain default TLB invalidation policy: %s mode %s\n",
               iommu_dma_strict ? "strict" : "lazy",
                (iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ?
                        "(set via kernel command line)" : "");

I think it's worth mentioning "default" somewhere, as not all IOMMUs or 
devices will use lazy mode even if it's default.

Thanks,
John

WARNING: multiple messages have this Message-ID (diff)
From: John Garry <john.garry@huawei.com>
To: Robin Murphy <robin.murphy@arm.com>, <joro@8bytes.org>,
	<will@kernel.org>
Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
	hch@lst.de
Subject: Re: [PATCH] iommu: Print default strict or lazy mode at init time
Date: Tue, 1 Jun 2021 16:50:39 +0100	[thread overview]
Message-ID: <e478aea8-54d3-bfc6-1bc8-b0c7709e353a@huawei.com> (raw)
In-Reply-To: <3ee986a0-29c1-100c-c72f-360f919caf7d@arm.com>

On 01/06/2021 10:09, Robin Murphy wrote:
>> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
>> index 808ab70d5df5..f25fae62f077 100644
>> --- a/drivers/iommu/iommu.c
>> +++ b/drivers/iommu/iommu.c
>> @@ -138,6 +138,11 @@ static int __init iommu_subsys_init(void)
>>           (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
>>               "(set via kernel command line)" : "");
>> +    pr_info("Default DMA domain mode: %s %s\n",
> 
> Nit: I think this might be a little unclear for end-users - *I'm* not 
> even sure whether "Default" here is meant to refer to the mode setting 
> itself or to default domains (of DMA type). Maybe something like "DMA 
> domain TLB invalidation policy"? Certainly it seems like a good idea to 
> explicitly mention invalidation to correlate with the documentation of 
> the "iommu.strict" parameter.
> 
> Ack to the general idea though.

ok, so I'll go with this:

pr_info("DMA domain default TLB invalidation policy: %s mode %s\n",
               iommu_dma_strict ? "strict" : "lazy",
                (iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ?
                        "(set via kernel command line)" : "");

I think it's worth mentioning "default" somewhere, as not all IOMMUs or 
devices will use lazy mode even if it's default.

Thanks,
John
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

  reply	other threads:[~2021-06-01 15:51 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-28 13:37 [PATCH] iommu: Print default strict or lazy mode at init time John Garry
2021-05-28 13:37 ` John Garry
2021-06-01  9:09 ` Robin Murphy
2021-06-01  9:09   ` Robin Murphy
2021-06-01 15:50   ` John Garry [this message]
2021-06-01 15:50     ` John Garry
2021-06-01 16:42     ` Robin Murphy
2021-06-01 16:42       ` Robin Murphy
2021-06-01 17:44       ` John Garry
2021-06-01 17:44         ` John Garry

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