linux-kernel - Re: [PATCH v8 13/13] iommu/amd: Disable iommu only if amd

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Date:   Thu, 27 Jul 2017 17:58:52 +0200
From:   Joerg Roedel <jroedel@...e.de>
To:     Baoquan He <bhe@...hat.com>
Cc:     iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        root <root@...-dinar-02.lab.bos.redhat.com>
Subject: Re: [PATCH v8 13/13] iommu/amd: Disable iommu only if amd_iommu=off
 is specified

On Fri, Jul 21, 2017 at 04:59:11PM +0800, Baoquan He wrote:
> From: root <root@...-dinar-02.lab.bos.redhat.com>

You probaly need to reset the author on this one.

> 
> It's ok to disable iommu in normal kernel. While there's no need
> to disable it in kdump kernel after the on-flight dma issue has
> heen fixed.
> 
> Signed-off-by: Baoquan He <bhe@...hat.com>
> ---
>  drivers/iommu/amd_iommu_init.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
> index 8b4bac978062..880f693c809b 100644
> --- a/drivers/iommu/amd_iommu_init.c
> +++ b/drivers/iommu/amd_iommu_init.c
> @@ -2494,7 +2494,8 @@ static int __init early_amd_iommu_init(void)
>  		goto out;
>  
>  	/* Disable any previously enabled IOMMUs */
> -	disable_iommus();
> +	if (amd_iommu_disabled)
> +		disable_iommus();
>  
>  	if (amd_iommu_irq_remap)
>  		amd_iommu_irq_remap = check_ioapic_information();
> -- 
> 2.5.5