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Message-ID: <e26db44c-ec72-085d-13ee-597237ba2134@linux.intel.com>
Date:   Wed, 12 Jul 2023 11:13:08 +0800
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Cc:     baolu.lu@linux.intel.com, Joerg Roedel <joro@8bytes.org>,
        Will Deacon <will@kernel.org>,
        Robin Murphy <robin.murphy@arm.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        Kevin Tian <kevin.tian@intel.com>,
        Jean-Philippe Brucker <jean-philippe@linaro.org>,
        Nicolin Chen <nicolinc@nvidia.com>,
        Yi Liu <yi.l.liu@intel.com>, iommu@lists.linux.dev,
        kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 9/9] iommu: Use fault cookie to store iopf_param
Content-Language: en-US
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>
References: <20230711010642.19707-1-baolu.lu@linux.intel.com>
 <20230711010642.19707-10-baolu.lu@linux.intel.com>
 <20230711150249.62917dad@jacob-builder>
From:   Baolu Lu <baolu.lu@linux.intel.com>
In-Reply-To: <20230711150249.62917dad@jacob-builder>
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On 2023/7/12 6:02, Jacob Pan wrote:
> On Tue, 11 Jul 2023 09:06:42 +0800, Lu Baolu<baolu.lu@linux.intel.com>
> wrote:
> 
>> Remove the static iopf_param pointer from struct iommu_fault_param to
>> save memory.
>>
>> Signed-off-by: Lu Baolu<baolu.lu@linux.intel.com>
>> ---
>>   include/linux/iommu.h      |  2 --
>>   drivers/iommu/io-pgfault.c | 47 +++++++++++++++++++++++---------------
>>   2 files changed, 29 insertions(+), 20 deletions(-)
>>
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index ffd6fe1317f4..5fe37a7c5a55 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -551,7 +551,6 @@ struct iommu_fault_param {
>>    * struct dev_iommu - Collection of per-device IOMMU data
>>    *
>>    * @fault_param: IOMMU detected device fault reporting data
>> - * @iopf_param:	 I/O Page Fault queue and data
>>    * @fwspec:	 IOMMU fwspec data
>>    * @iommu_dev:	 IOMMU device this device is linked to
>>    * @priv:	 IOMMU Driver private data
>> @@ -564,7 +563,6 @@ struct iommu_fault_param {
>>   struct dev_iommu {
>>   	struct mutex lock;
>>   	struct iommu_fault_param	*fault_param;
>> -	struct iopf_device_param	*iopf_param;
>>   	struct iommu_fwspec		*fwspec;
>>   	struct iommu_device		*iommu_dev;
>>   	void				*priv;
>> diff --git a/drivers/iommu/io-pgfault.c b/drivers/iommu/io-pgfault.c
>> index 1749e0869f2e..6a3a4e08e67e 100644
>> --- a/drivers/iommu/io-pgfault.c
>> +++ b/drivers/iommu/io-pgfault.c
>> @@ -158,7 +158,7 @@ int iommu_queue_iopf(struct iommu_fault *fault,
>> struct device *dev)
>>   	 * As long as we're holding param->lock, the queue can't be
>> unlinked
>>   	 * from the device and therefore cannot disappear.
>>   	 */
>> -	iopf_param = param->iopf_param;
>> +	iopf_param = iommu_get_device_fault_cookie(dev, 0);
> I am not sure I understand how does it know the cookie type is iopf_param
> for PASID 0?
> 
> Between IOPF and IOMMUFD use of the cookie, cookie types are different,
> right?
> 

The fault cookie is managed by the code that delivers or handles the
faults. The sva and IOMMUFD paths are exclusive.

Best regards,
baolu