linux-kernel - Re: [RFC PATCH v1 07/38] iommufd/viommu: Add support to associate viommu with kvm instance

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <yq5azfcn9z6p.fsf@kernel.org>
Date: Tue, 29 Jul 2025 14:00:22 +0530
From: Aneesh Kumar K.V <aneesh.kumar@...nel.org>
To: Jason Gunthorpe <jgg@...pe.ca>
Cc: linux-coco@...ts.linux.dev, kvmarm@...ts.linux.dev,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org, aik@....com,
	lukas@...ner.de, Samuel Ortiz <sameo@...osinc.com>,
	Xu Yilun <yilun.xu@...ux.intel.com>,
	Suzuki K Poulose <Suzuki.Poulose@....com>,
	Steven Price <steven.price@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Marc Zyngier <maz@...nel.org>, Will Deacon <will@...nel.org>,
	Oliver Upton <oliver.upton@...ux.dev>
Subject: Re: [RFC PATCH v1 07/38] iommufd/viommu: Add support to associate
 viommu with kvm instance

Jason Gunthorpe <jgg@...pe.ca> writes:

> On Mon, Jul 28, 2025 at 07:21:44PM +0530, Aneesh Kumar K.V (Arm) wrote:
>
>> +#if IS_ENABLED(CONFIG_KVM)
>> +#include <linux/kvm_host.h>
>> +
>> +static int viommu_get_kvm(struct iommufd_viommu *viommu, int kvm_vm_fd)
>> +{
>> +	int rc = -EBADF;
>> +	struct file *filp;
>> +
>> +	filp = fget(kvm_vm_fd);
>> +
>> +	if (!file_is_kvm(filp))
>> +		goto err_out;
>> +
>> +	/* hold the kvm reference via file descriptor */
>> +	viommu->kvm_filp = filp;
>> +	return 0;
>> +err_out:
>> +	viommu->kvm_filp = NULL;
>> +	fput(filp);
>> +	return rc;
>> +}
>> +
>> +static void viommu_put_kvm(struct iommufd_viommu *viommu)
>> +{
>> +	fput(viommu->kvm_filp);
>> +	viommu->kvm_filp = NULL;
>> +}
>> +#endif
>
> Missing stub functions for !CONFIG_KVM?
>
> Looks like an OK design otherwise
>
>> @@ -1057,6 +1068,7 @@ struct iommu_viommu_alloc {
>>  	__u32 data_len;
>>  	__u32 __reserved;
>>  	__aligned_u64 data_uptr;
>> +	__u32 kvm_vm_fd;
>
> fds are __s32, they are signed numbers.
>

Thanks for the review comments. I’ll update the patch with the suggested changes.

-aneesh