linux-kernel - Re: [RFC PATCH 00/21] VFIO live update support

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: <20251018225309.GF1034710.vipinsh@google.com>
Date: Sat, 18 Oct 2025 15:53:09 -0700
From: Vipin Sharma <vipinsh@...gle.com>
To: Jason Gunthorpe <jgg@...pe.ca>
Cc: bhelgaas@...gle.com, alex.williamson@...hat.com,
	pasha.tatashin@...een.com, dmatlack@...gle.com, graf@...zon.com,
	pratyush@...nel.org, gregkh@...uxfoundation.org, chrisl@...nel.org,
	rppt@...nel.org, skhawaja@...gle.com, parav@...dia.com,
	saeedm@...dia.com, kevin.tian@...el.com, jrhilke@...gle.com,
	david@...hat.com, jgowans@...zon.com, dwmw2@...radead.org,
	epetron@...zon.de, junaids@...gle.com, linux-kernel@...r.kernel.org,
	linux-pci@...r.kernel.org, kvm@...r.kernel.org,
	linux-kselftest@...r.kernel.org
Subject: Re: [RFC PATCH 00/21] VFIO live update support

On 2025-10-18 14:21:30, Jason Gunthorpe wrote:
> On Fri, Oct 17, 2025 at 05:06:52PM -0700, Vipin Sharma wrote:
> > 2. Integration with IOMMUFD and PCI series for complete workflow where a
> >    device continues a DMA while undergoing through live update.
> 
> It is a bit confusing, this series has PCI components so how does it
> relate the PCI series? Is this self contained for at least limited PCI
> topologies?

This series has very minimal PCI support. For example, it is skipping
DMA disable on the VFIO PCI device during kexec reboot and saving initial PCI
state during first open (bind) of the device.

We do need proper PCI support, few examples:

- Not disabling DMA bit on bridges upstream of the leaf VFIO PCI device node. 
- Not writing to PCI config during device enumeration.
- Not autobinding devices to their default driver. My testing works on
  devices which don't have driver bulit in the kernel so there is no
  probing by other drivers.
- PCI enable and disable calls support.

These things I think should be solved in PCI series.