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Date:   Tue, 16 Mar 2021 14:16:34 +0100
From:   Joerg Roedel <jroedel@suse.de>
To:     Huang Rui <ray.huang@amd.com>
Cc:     iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
        Joerg Roedel <joro@8bytes.org>,
        Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>,
        Xiaojian Du <xiaojian.du@amd.com>, stable@vger.kernel.org
Subject: Re: [PATCH] iommu/amd: Fix iommu remap panic while amd_iommu is set
 to disable
Message-ID: <YFCvsort3oZGfDBy@suse.de>
References: <20210311142807.705080-1-ray.huang@amd.com>
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In-Reply-To: <20210311142807.705080-1-ray.huang@amd.com>
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Hi Huang,

On Thu, Mar 11, 2021 at 10:28:07PM +0800, Huang Rui wrote:
> diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
> index f0adbc48fd17..a08e885403b7 100644
> --- a/drivers/iommu/amd/iommu.c
> +++ b/drivers/iommu/amd/iommu.c
> @@ -3862,7 +3862,7 @@ static int irq_remapping_select(struct irq_domain *d, struct irq_fwspec *fwspec,
>  	else if (x86_fwspec_is_hpet(fwspec))
>  		devid = get_hpet_devid(fwspec->param[0]);
>  
> -	if (devid < 0)
> +	if (devid < 0 || !amd_iommu_rlookup_table)
>  		return 0;

The problem is deeper than this fix suggests. I prepared other fixes for
this particular problem. Please find them here:

	https://git.kernel.org/pub/scm/linux/kernel/git/joro/linux.git/log/?h=iommu-fixes

Regards,

	Joerg