linux-kernel - Re: [PATCH v8 14/18] mm: memfd

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Message-ID: <20260107185414.GG293394@nvidia.com>
Date: Wed, 7 Jan 2026 14:54:14 -0400
From: Jason Gunthorpe <jgg@...dia.com>
To: Pasha Tatashin <pasha.tatashin@...een.com>
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Subject: Re: [PATCH v8 14/18] mm: memfd_luo: allow preserving memfd

On Tue, Nov 25, 2025 at 11:58:44AM -0500, Pasha Tatashin wrote:
> From: Pratyush Yadav <ptyadav@...zon.de>
> 
> The ability to preserve a memfd allows userspace to use KHO and LUO to
> transfer its memory contents to the next kernel. This is useful in many
> ways. For one, it can be used with IOMMUFD as the backing store for
> IOMMU page tables. Preserving IOMMUFD is essential for performing a
> hypervisor live update with passthrough devices. memfd support provides
> the first building block for making that possible.

I would lead with the use of memfd to back the guest memory pages for
use with KVM :)

Jason