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Subject: Re: [PATCH v3 02/16] iommu: Introduce cache_invalidate API
To:     Jean-Philippe Brucker <jean-philippe.brucker@arm.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        "iommu@lists.linux-foundation.org" <iommu@lists.linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Joerg Roedel <joro@8bytes.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Alex Williamson <alex.williamson@redhat.com>
Cc:     "Tian, Kevin" <kevin.tian@intel.com>,
        Raj Ashok <ashok.raj@intel.com>,
        Andriy Shevchenko <andriy.shevchenko@linux.intel.com>
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From:   Auger Eric <eric.auger@redhat.com>
Message-ID: <1edd45e6-4da3-e393-36b2-9e63cd5f7607@redhat.com>
Date:   Tue, 14 May 2019 09:46:35 +0200
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Hi Jean,

On 5/13/19 7:09 PM, Jean-Philippe Brucker wrote:
> On 13/05/2019 17:50, Auger Eric wrote:
>>> struct iommu_inv_pasid_info {
>>> #define IOMMU_INV_PASID_FLAGS_PASID	(1 << 0)
>>> #define IOMMU_INV_PASID_FLAGS_ARCHID	(1 << 1)
>>> 	__u32	flags;
>>> 	__u32	archid;
>>> 	__u64	pasid;
>>> };
>> I agree it does the job now. However it looks a bit strange to do a
>> PASID based invalidation in my case - SMMUv3 nested stage - where I
>> don't have any PASID involved.
>>
>> Couldn't we call it context based invalidation then? A context can be
>> tagged by a PASID or/and an ARCHID.
> 
> I think calling it "context" would be confusing as well (I shouldn't
> have used it earlier), since VT-d uses that name for device table
> entries (=STE on Arm SMMU). Maybe "addr_space"?
yes you're right. Well we already pasid table table terminology so we
can use it here as well - as long as we understand what purpose it
serves ;-) - So OK for iommu_inv_pasid_info.

I think Jean understood we would keep pasid standalone field in
iommu_cache_invalidate_info's union. I understand the struct
iommu_inv_pasid_info now would replace it, correct?

Thanks

Eric
> 
> Thanks,
> Jean
> 
>>
>> Domain invalidation would invalidate all the contexts belonging to that
>> domain.
>>
>> Thanks
>>
>> Eric