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b=UUcumPy0BYvtdOojDqRMbxskHsPm5uBsBYmhtRJN2Cr5nP5SNAalBjOZBxdBot2ftdXNw/44+9FvJB9/EoYMhNWENVecNqy0f2YAS8+5Lz7xEjJoCv9r72zwVZDctMIKLkrzd6c1Hd2THfX0lOlhefu+2Ooi3cCPGb4GLgxGWko= Authentication-Results: mx.microsoft.com 1; dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from BL4PR12MB9505.namprd12.prod.outlook.com (2603:10b6:208:591::16) by IA0PR12MB8974.namprd12.prod.outlook.com (2603:10b6:208:488::21) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.472.16; Wed, 30 Sep 2026 13:28:16 +0000 Received: from BL4PR12MB9505.namprd12.prod.outlook.com ([fe80::73aa:eb8c:a86b:5a83]) by BL4PR12MB9505.namprd12.prod.outlook.com ([fe80::73aa:eb8c:a86b:5a83%5]) with mapi id 15.21.0451.022; Wed, 30 Sep 2026 13:28:15 +0000 Message-ID: <76d51545-47d3-4ef7-bb10-551c898c0968@amd.com> Date: Wed, 30 Sep 2026 18:58:05 +0530 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH v6 04/11] iommufd/viommu: Keep a reference to the KVM file To: "Aneesh Kumar K.V (Arm)" , linux-coco@lists.linux.dev, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: Jason Gunthorpe , Alexey Kardashevskiy , Bjorn Helgaas , Joerg Roedel , Jonathan Cameron , Kevin Tian , Nicolin Chen , Samuel Ortiz , Steven Price , Suzuki K Poulose , Will Deacon , Xu Yilun , Shameer Kolothum , Paolo Bonzini References: <20260917140159.1163281-1-aneesh.kumar@kernel.org> <20260917140159.1163281-5-aneesh.kumar@kernel.org> Content-Language: en-US From: Vasant Hegde In-Reply-To: <20260917140159.1163281-5-aneesh.kumar@kernel.org> Content-Type: text/plain; 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Save the device's KVM file in the iommufd_viommu when the > vIOMMU is allocated, and take a file reference so it remains valid for the > lifetime of the vIOMMU. > > Release the reference when the vIOMMU is destroyed. > > Based on an original patch by Shameer Kolothum > > [nicolinc: hold kvm's users_count] > Signed-off-by: Nicolin Chen > [aneesh.kumar: Switch to use kvm_file] > Signed-off-by: Aneesh Kumar K.V (Arm) > --- > drivers/iommu/iommufd/viommu.c | 5 +++++ > include/linux/iommufd.h | 1 + > 2 files changed, 6 insertions(+) > > diff --git a/drivers/iommu/iommufd/viommu.c b/drivers/iommu/iommufd/viommu.c > index 4081deda9b33..bf5d58d55939 100644 > --- a/drivers/iommu/iommufd/viommu.c > +++ b/drivers/iommu/iommufd/viommu.c > @@ -1,6 +1,7 @@ > // SPDX-License-Identifier: GPL-2.0-only > /* Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES > */ > +#include > #include "iommufd_private.h" > > void iommufd_viommu_destroy(struct iommufd_object *obj) > @@ -11,6 +12,8 @@ void iommufd_viommu_destroy(struct iommufd_object *obj) > if (viommu->ops && viommu->ops->destroy) > viommu->ops->destroy(viommu); > refcount_dec(&viommu->hwpt->common.obj.users); > + if (viommu->kvm_file) > + fput(viommu->kvm_file); > xa_destroy(&viommu->vdevs); > } > > @@ -76,6 +79,8 @@ int iommufd_viommu_alloc_ioctl(struct iommufd_ucmd *ucmd) > } > > xa_init(&viommu->vdevs); > + if (idev->kvm_file) > + viommu->kvm_file = get_file(idev->kvm_file); Nice! This is needed for AMD IOMMU as well! Minor nit. You have to add fput() in error path. -Vasant