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Date:   Fri, 13 Jan 2023 11:35:46 -0400
From:   Jason Gunthorpe <jgg@ziepe.ca>
To:     Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Cc:     linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
        joro@8bytes.org, robin.murphy@arm.com, ashish.kalra@amd.com,
        thomas.lendacky@amd.com, vasant.hegde@amd.com, jon.grimm@amd.com
Subject: Re: [PATCH 3/4] iommu: Introduce IOMMU call-back for processing
 struct KVM assigned to VFIO
Message-ID: <Y8F6Uoi73BK6R+mc@ziepe.ca>
References: <20230110143137.54517-1-suravee.suthikulpanit@amd.com>
 <20230110143137.54517-4-suravee.suthikulpanit@amd.com>
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On Tue, Jan 10, 2023 at 08:31:36AM -0600, Suravee Suthikulpanit wrote:
> Currently, VFIO provide an kvm_vfio_file_set_kvm() interface for assigning
> a KVM structure to a VFIO group. The information in struct KVM is also
> useful for IOMMU drivers when setting up VFIO domain.
> 
> Introduce struct iommu_domain_ops.set_kvm call-back function to allow
> IOMMU drivers to provide call-back to process the struct KVM
> assigned.

Also NAK

Connecting the iommu driver to KVM has to be properly architected
though iommufd.

> @@ -1652,6 +1652,7 @@ void vfio_file_set_kvm(struct file *file, struct kvm *kvm)
>  
>  	mutex_lock(&group->group_lock);
>  	group->kvm = kvm;
> +	iommu_set_kvm(group->iommu_group, kvm);
>  	mutex_unlock(&group->group_lock);
>  }

This also has obvious lifetime bugs

Jason