linux-kernel - Re: [PATCH v2 24/24] iommu: Only log strictness for DMA domains

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d679940d-6781-c850-7eb1-07b7b0864d2a@huawei.com>
Date:   Thu, 29 Jul 2021 10:04:31 +0100
From:   John Garry <john.garry@...wei.com>
To:     Robin Murphy <robin.murphy@....com>, <joro@...tes.org>,
        <will@...nel.org>
CC:     <iommu@...ts.linux-foundation.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <suravee.suthikulpanit@....com>,
        <baolu.lu@...ux.intel.com>, <dianders@...omium.org>
Subject: Re: [PATCH v2 24/24] iommu: Only log strictness for DMA domains

On 28/07/2021 16:58, Robin Murphy wrote:
> When passthrough is enabled, the default strictness policy becomes
> irrelevant, since any subsequent runtime override to a DMA domain type
> now embodies an explicit choice of strictness as well. Save on noise by
> only logging the default policy when it is meaningfully in effect.
> 
> Signed-off-by: Robin Murphy<robin.murphy@....com>

FWIW, small comment below,

Reviewed-by: John Garry <john.garry@...wei.com>

> ---
>   drivers/iommu/iommu.c | 9 +++++----
>   1 file changed, 5 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index be399d630953..87d7b299436e 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -144,10 +144,11 @@ static int __init iommu_subsys_init(void)
>   		(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
>   			"(set via kernel command line)" : "");
>   
> -	pr_info("DMA domain TLB invalidation policy: %s mode %s\n",
> -		iommu_dma_strict ? "strict" : "lazy",
> -		(iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ?
> -			"(set via kernel command line)" : "");
> +	if (!iommu_default_passthrough())

I suppose that you could also do an early return to save indenting...


> +		pr_info("DMA domain TLB invalidation policy: %s mode %s\n",
> +			iommu_dma_strict ? "strict" : "lazy",
> +			(iommu_cmd_line & IOMMU_CMD_LINE_STRICT) ?
> +				"(set via kernel command line)" : "");
>   
>   	return 0;
>   }