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Date:   Sat, 25 Jun 2022 22:06:31 -0700
From:   Fenghua Yu <fenghua.yu@intel.com>
To:     Jerry Snitselaar <jsnitsel@redhat.com>
Cc:     dmaengine@vger.kernel.org, Vinod Koul <vkoul@kernel.org>,
        linux-kernel@vger.kernel.org, Dave Jiang <dave.jiang@intel.com>
Subject: Re: [PATCH v2] dmaengine: idxd: Only call idxd_enable_system_pasid()
 if succeeded in enabling SVA feature
Message-ID: <YrfpV5kcyRj2LdZB@fyu1.sc.intel.com>
References: <20220625221333.214589-1-jsnitsel@redhat.com>
 <20220626045144.9063-1-jsnitsel@redhat.com>
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In-Reply-To: <20220626045144.9063-1-jsnitsel@redhat.com>
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Hi, Jerry,

On Sat, Jun 25, 2022 at 09:51:44PM -0700, Jerry Snitselaar wrote:
> On a Sapphire Rapids system if you boot without intel_iommu=on, the IDXD
                               s/you//

> driver will crash during probe in iommu_sva_bind_device().
.... 
> v2: Balance braces on if else block. Fix up commit description.

This change log should be moved after "---".

> 
> Fixes: 42a1b73852c4 ("dmaengine: idxd: Separate user and kernel pasid enabling")
> Cc: Vinod Koul <vkoul@kernel.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Fenghua Yu <fenghua.yu@intel.com>
> Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>

Please put the bug report link here:

Link: https://lore.kernel.org/dmaengine/20220623170232.6whonfjuh3m5vcoy@cantor/

> ---

i.e. put the change log here:

v2: Balance braces on if else block. Fix up commit description.

>  drivers/dma/idxd/init.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index 355fb3ef4cbf..aa3478257ddb 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -512,15 +512,16 @@ static int idxd_probe(struct idxd_device *idxd)
>  	dev_dbg(dev, "IDXD reset complete\n");
>  
>  	if (IS_ENABLED(CONFIG_INTEL_IDXD_SVM) && sva) {
> -		if (iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA))
> +		if (iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA)) {
>  			dev_warn(dev, "Unable to turn on user SVA feature.\n");
> -		else
> +		} else {
>  			set_bit(IDXD_FLAG_USER_PASID_ENABLED, &idxd->flags);
>  
> -		if (idxd_enable_system_pasid(idxd))
> -			dev_warn(dev, "No in-kernel DMA with PASID.\n");
> -		else
> -			set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
> +			if (idxd_enable_system_pasid(idxd))
> +				dev_warn(dev, "No in-kernel DMA with PASID.\n");
> +			else
> +				set_bit(IDXD_FLAG_PASID_ENABLED, &idxd->flags);
> +		}
>  	} else if (!sva) {
>  		dev_warn(dev, "User forced SVA off via module param.\n");
>  	}
> -- 
> 2.36.1
> 
Thanks.

-Fenghua