ACK: [SRU][O/N][PATCH 0/3] Backport pci=config_acs parameter with fix commit

[Kuba Pawlak]

On 6.05.2025 00:57, Jacob Martin wrote:
> BugLink: https://bugs.launchpad.net/bugs/2100340
>
> SRU Justification:
>
> [Impact]
>
> The PCI ACS capability parameter is used to enable and configure access
> control between PCIe devices. In particular, this parameter can enable
> and/or restrict peer-to-peer traffic between so-configured PCIe devices.
>
> For example, this parameter is necessary for GPUDirect RDMA
> applications, where peer-to-peer communication between a GPU and an
> RDMA-capable device is required. This parameter allows an administrator
> to configure the system for the specific level of isolation between PCIe
> devices required to enable this feature for their use case.
>
> [Fix]
>
> For Oracular, this consists of a clean cherry pick from mainline of
> commit 9cf8a952d57b ("PCI/ACS: Fix 'pci=config_acs=' parameter") to fix
> the functionality of the config_acs parameter introduced by commit
> 47c8846a49ba ("PCI: Extend ACS configurability").
>
> For Noble, this consists of clean cherry picks of commits 47c8846a49ba
> ("PCI: Extend ACS configurability") and 9cf8a952d57b ("PCI/ACS: Fix
> 'pci=config_acs=' parameter").
>
> [Test Plan]
>
> The Noble and Oracular patchsets were tested on a DGX GH200 system by
> booting with the kernel parameter test cases described in the commit
> message of 9cf8a952d57b ("PCI/ACS: Fix 'pci=config_acs=' parameter").
>
> Multiple PCIe devices could be configured with the pci=config_acs
> parameter as is expected with the fix commit, and pci=disable_acs_redir
> works as expected.
>
> [Where problems could occur]
>
> This affects the pci=config_acs and pci=config_acs_redir kernel boot
> parameters. Issues could arise as malfunctioning of these two boot
> parameters, or as improper configuration of PCIe devices.
>
Acked-by: Kuba Pawlak <kuba.pawlak at canonical.com>
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