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From: Will Deacon <will@kernel.org>
To: Jordan Crouse <jcrouse@codeaurora.org>
Cc: freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Robin Murphy <robin.murphy@arm.com>,
	Joerg Roedel <joro@8bytes.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 5/7] iommu/arm-smmu: Support DOMAIN_ATTR_SPLIT_TABLES
Date: Tue, 17 Sep 2019 18:20:20 +0100
Message-ID: <20190917172020.hpv5qqdpihvqkehp@willie-the-truck> (raw)
In-Reply-To: <1566327992-362-6-git-send-email-jcrouse@codeaurora.org>

On Tue, Aug 20, 2019 at 01:06:30PM -0600, Jordan Crouse wrote:
> Support the DOMAIN_ATTR_SPLIT_TABLES attribute to let the leaf driver
> know if split pagetables are enabled for the domain.
> 
> Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
> ---
> 
>  drivers/iommu/arm-smmu.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index 3f41cf7..6a512ff 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1442,6 +1442,9 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
>  		case DOMAIN_ATTR_NESTING:
>  			*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
>  			return 0;
> +		case DOMAIN_ATTR_SPLIT_TABLES:
> +			*(int *)data = !!(smmu_domain->split_pagetables);
> +			return 0;

Hmm. Could you move the setting of this attribute into
arm_smmu_domain_set_attr() and reject it if the ias != 48 in there? That way
the user of the domain can request this feature, rather than us enforcing it
based on the compatible string.

I'd also prefer to call it DOMAIN_ATTR_USE_TTBR1 instead, since it's pretty
ARM specific at this point.

Will

  reply index

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-20 19:06 [PATCH 0/7] iommu/arm-smmu: Split pagetable support for Adreno GPUs Jordan Crouse
2019-08-20 19:06 ` [PATCH 1/7] iommu/arm-smmu: Support split pagetables Jordan Crouse
2019-08-20 19:06 ` [PATCH 2/7] dt-bindings: arm-smmu: Add Adreno GPU variant Jordan Crouse
2019-08-27 17:13   ` Rob Herring
2019-09-17 18:56   ` Stephen Boyd
2019-08-20 19:06 ` [PATCH 3/7] iommu/arm-smmu: Add a SMMU variant for the Adreno GPU Jordan Crouse
2019-09-17 18:55   ` Stephen Boyd
2019-08-20 19:06 ` [PATCH 4/7] iommu: Add DOMAIN_ATTR_SPLIT_TABLES Jordan Crouse
2019-08-20 19:06 ` [PATCH 5/7] iommu/arm-smmu: Support DOMAIN_ATTR_SPLIT_TABLES Jordan Crouse
2019-09-17 17:20   ` Will Deacon [this message]
2019-08-20 19:06 ` [PATCH 6/7] drm/msm: Create the msm_mmu object independently from the address space Jordan Crouse
2019-08-20 19:06 ` [PATCH 7/7] drm/msm: Use per-target functions to set up address spaces Jordan Crouse

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