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From: Jon Hunter <jonathanh@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>, Krishna Reddy <vdumpa@nvidia.com>
Cc: talho@nvidia.com, treding@nvidia.com, bhuntsman@nvidia.com,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	mperttunen@nvidia.com, nicoleotsuka@gmail.com, snikam@nvidia.com,
	nicolinc@nvidia.com, linux-tegra@vger.kernel.org,
	yhsu@nvidia.com, praithatha@nvidia.com, will@kernel.org,
	linux-arm-kernel@lists.infradead.org, bbiswas@nvidia.com
Subject: Re: [PATCH v8 3/3] iommu/arm-smmu: Add global/context fault implementation hooks
Date: Tue, 30 Jun 2020 13:42:52 +0100	[thread overview]
Message-ID: <fd1f1102-ab05-002a-a86a-d3c6cef21e01@nvidia.com> (raw)
In-Reply-To: <6c2ce909-c71b-351f-79f5-b1a4b4c0e4ac@arm.com>


On 30/06/2020 13:13, Robin Murphy wrote:
> On 2020-06-30 09:37, Jon Hunter wrote:
>>
>> On 30/06/2020 01:10, Krishna Reddy wrote:
>>> Add global/context fault hooks to allow NVIDIA SMMU implementation
>>> handle faults across multiple SMMUs.
>>
>> Nit ... this is not just for NVIDIA, but this allows anyone to add
>> custom global/context and fault hooks. So I think that the changelog
>> should be clear that this change permits custom fault hooks and that
>> custom fault hooks are needed for the Tegra194 SMMU. You may also want
>> to say why.
>>
>>>
>>> Signed-off-by: Krishna Reddy <vdumpa@nvidia.com>
>>> ---
>>>   drivers/iommu/arm-smmu-nvidia.c | 98 +++++++++++++++++++++++++++++++++
>>>   drivers/iommu/arm-smmu.c        | 17 +++++-
>>>   drivers/iommu/arm-smmu.h        |  3 +
>>>   3 files changed, 116 insertions(+), 2 deletions(-)

...

>>> @@ -835,7 +836,13 @@ static int arm_smmu_init_domain_context(struct
>>> iommu_domain *domain,
>>>        * handler seeing a half-initialised domain state.
>>>        */
>>>       irq = smmu->irqs[smmu->num_global_irqs + cfg->irptndx];
>>> -    ret = devm_request_irq(smmu->dev, irq, arm_smmu_context_fault,
>>> +
>>> +    if (smmu->impl && smmu->impl->context_fault)
>>> +        context_fault = smmu->impl->context_fault;
>>> +    else
>>> +        context_fault = arm_smmu_context_fault;
>>
>> Why not see the default smmu->impl->context_fault to
>> arm_smmu_context_fault in arm_smmu_impl_init() and then allow the
>> various implementations to override as necessary? Then you can get rid
>> of this context_fault variable here and just use
>> smmu->impl->context_fault below.
> 
> Because the default smmu->impl is NULL. And as I've said before, NAK to
> forcing the common case to allocate a set of "quirks" purely to override
> the default IRQ handler with the default IRQ handler ;)


Ah OK, makes sense. Sorry I am a bit late to the review :-)

Jon

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  reply	other threads:[~2020-06-30 12:43 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-30  0:10 [PATCH v8 0/3] Nvidia Arm SMMUv2 Implementation Krishna Reddy
2020-06-30  0:10 ` [PATCH v8 1/3] iommu/arm-smmu: add NVIDIA implementation for dual ARM MMU-500 usage Krishna Reddy
2020-06-30  0:16   ` Nicolin Chen
2020-06-30  5:54   ` Pritesh Raithatha
2020-06-30  8:19   ` Jon Hunter
2020-06-30 14:53     ` Robin Murphy
2020-06-30 15:17       ` Jon Hunter
2020-07-01 18:18       ` Krishna Reddy
2020-07-01 18:56         ` Robin Murphy
2020-07-01 19:12           ` Krishna Reddy
2020-06-30 17:04     ` Krishna Reddy
2020-06-30 10:17   ` Jon Hunter
2020-06-30 16:23     ` Krishna Reddy
2020-06-30 16:32       ` Jon Hunter
2020-06-30 16:44         ` Jon Hunter
2020-06-30 17:16           ` Krishna Reddy
2020-06-30 19:03             ` Jon Hunter
2020-06-30 20:21               ` Krishna Reddy
2020-06-30  0:10 ` [PATCH v8 2/3] dt-bindings: arm-smmu: Add binding for Tegra194 SMMU Krishna Reddy
2020-06-30  6:01   ` Pritesh Raithatha
2020-06-30  8:21   ` Jon Hunter
2020-06-30 12:27   ` Robin Murphy
2020-07-01 18:28     ` Krishna Reddy
2020-07-01 18:47       ` Jon Hunter
2020-07-01 19:00         ` Krishna Reddy
2020-07-01 19:31           ` Jon Hunter
2020-07-01 19:39             ` Krishna Reddy
2020-07-02 16:05               ` Robin Murphy
2020-07-01 19:03         ` Robin Murphy
2020-06-30  0:10 ` [PATCH v8 3/3] iommu/arm-smmu: Add global/context fault implementation hooks Krishna Reddy
2020-06-30  0:19   ` Nicolin Chen
2020-06-30  5:58   ` Pritesh Raithatha
2020-06-30  8:37   ` Jon Hunter
2020-06-30 12:13     ` Robin Murphy
2020-06-30 12:42       ` Jon Hunter [this message]
2020-07-01 18:48       ` Krishna Reddy
2020-07-01 19:14         ` Robin Murphy
2020-07-01 19:22           ` Krishna Reddy

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