Re: [PATCH v6 03/29] iommu/arm-smmu-v3: Do not allow a SVA domain to be set on the wrong PASID

From: Mostafa Saleh <smostafa@google.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: iommu@lists.linux.dev, Joerg Roedel <joro@8bytes.org>,
	linux-arm-kernel@lists.infradead.org,
	Robin Murphy <robin.murphy@arm.com>,
	Will Deacon <will@kernel.org>,
	Lu Baolu <baolu.lu@linux.intel.com>,
	Eric Auger <eric.auger@redhat.com>,
	Jean-Philippe Brucker <jean-philippe@linaro.org>,
	Joerg Roedel <jroedel@suse.de>, Kevin Tian <kevin.tian@intel.com>,
	kernel test robot <lkp@intel.com>,
	Moritz Fischer <mdf@kernel.org>,
	Moritz Fischer <moritzf@google.com>,
	Michael Shavit <mshavit@google.com>,
	Nicolin Chen <nicolinc@nvidia.com>,
	patches@lists.linux.dev,
	Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>,
	Tony Zhu <tony.zhu@intel.com>, Yi Liu <yi.l.liu@intel.com>,
	Zhangfei Gao <zhangfei.gao@linaro.org>
Subject: Re: [PATCH v6 03/29] iommu/arm-smmu-v3: Do not allow a SVA domain to be set on the wrong PASID
Date: Thu, 28 Mar 2024 13:18:10 +0000	[thread overview]
Message-ID: <ZgVuErNrG9EcbPbX@google.com> (raw)
In-Reply-To: <3-v6-228e7adf25eb+4155-smmuv3_newapi_p2_jgg@nvidia.com>

Hi Jason,

On Wed, Mar 27, 2024 at 03:07:49PM -0300, Jason Gunthorpe wrote:
> The SVA code is wired to assume that the SVA is programmed onto the
> mm->pasid. The current core code always does this, so it is fine.
> 
> Add a check for clarity.
> 
> Fixes: 386fa64fd52b ("arm-smmu-v3/sva: Add SVA domain support")
> Tested-by: Nicolin Chen <nicolinc@nvidia.com>
> Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> Reviewed-by: Mostafa Saleh <smostafa@google.com>

I think there might have been a mix up, this was patch 01 in v5,
I didn’t add a tag on it. I don’t have a problem with the patch.
I just think (based on my limited understanding and rules in[1])
that it is not a fix as (mentioned in the last thread) the only
caller in the tree calls it properly.
But that’s up to the driver/stable maintainers.

[1] https://www.kernel.org/doc/html/next/process/stable-kernel-rules.html
> Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> index 2cd433a9c8a0fa..41b44baef15e80 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> @@ -569,6 +569,9 @@ static int arm_smmu_sva_set_dev_pasid(struct iommu_domain *domain,
>  	int ret = 0;
>  	struct mm_struct *mm = domain->mm;
>  
> +	if (mm_get_enqcmd_pasid(mm) != id)
> +		return -EINVAL;
> +
>  	mutex_lock(&sva_lock);
>  	ret = __arm_smmu_sva_bind(dev, id, mm);
>  	mutex_unlock(&sva_lock);
> -- 
> 2.43.2
>

Thanks,
Mostafa

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