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From: Jason Gunthorpe <jgg@nvidia.com>
To: Michael Shavit <mshavit@google.com>
Cc: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, robin.murphy@arm.com,
	will@kernel.org, jean-philippe@linaro.org, nicolinc@nvidia.com
Subject: Re: [PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master
Date: Tue, 1 Aug 2023 20:53:34 -0300	[thread overview]
Message-ID: <ZMma/qk0otN9eyW3@nvidia.com> (raw)
In-Reply-To: <20230802023524.v3.6.Ice063dcf87d1b777a72e008d9e3406d2bcf6d876@changeid>

On Wed, Aug 02, 2023 at 02:35:23AM +0800, Michael Shavit wrote:
> @@ -2465,6 +2440,22 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
>  	if (smmu_domain->stage != ARM_SMMU_DOMAIN_BYPASS)
>  		master->ats_enabled = arm_smmu_ats_supported(master);
>  
> +	if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1) {
> +		if (!master->cd_table.cdtab) {
> +			ret = arm_smmu_alloc_cd_tables(master);
> +			if (ret) {

Again, I didn't look very closely at your locking, but what lock is
being held to protect the read of master->cd_table.cdtab ?

> +				master->domain = NULL;
> +				goto out_unlock;

This is only the domain lock:
	mutex_unlock(&smmu_domain->init_mutex);

Which is no longer sufficient.

You need some kind of lock in the master struct to protect the shared
cd table and everything in it?

Jason

  reply	other threads:[~2023-08-01 23:53 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-01 18:35 [PATCH v3 0/8] Refactor the SMMU's CD table ownership Michael Shavit
2023-08-01 18:35 ` [PATCH v3 1/8] iommu/arm-smmu-v3: Move ctx_desc out of s1_cfg Michael Shavit
2023-08-01 18:35 ` [PATCH v3 2/8] iommu/arm-smmu-v3: Replace s1_cfg with cdtab_cfg Michael Shavit
2023-08-01 23:48   ` Jason Gunthorpe
2023-08-01 18:35 ` [PATCH v3 3/8] iommu/arm-smmu-v3: Encapsulate ctx_desc_cfg init in alloc_cd_tables Michael Shavit
2023-08-01 18:35 ` [PATCH v3 4/8] iommu/arm-smmu-v3: move stall_enabled to the cd table Michael Shavit
2023-08-01 18:35 ` [PATCH v3 5/8] iommu/arm-smmu-v3: Refactor write_ctx_desc Michael Shavit
2023-08-01 23:50   ` Jason Gunthorpe
2023-08-01 18:35 ` [PATCH v3 6/8] iommu/arm-smmu-v3: Move CD table to arm_smmu_master Michael Shavit
2023-08-01 23:53   ` Jason Gunthorpe [this message]
2023-08-02 11:19     ` Michael Shavit
2023-08-02 11:51       ` Jason Gunthorpe
2023-08-01 18:35 ` [PATCH v3 7/8] iommu/arm-smmu-v3: Skip cd sync if CD table isn't active Michael Shavit
2023-08-01 18:35 ` [PATCH v3 8/8] iommu/arm-smmu-v3: Rename cdcfg to cd_table Michael Shavit

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