[PATCH v10 08/13] PCI: Save and restore the ACS Control register and Egress Control Vector

[sashiko-bot at kernel.org]

> Save the ACS Control register and the ACS Egress Control Vector in
> pci_save_state() and write them back in pci_restore_state(), instead of
> recomputing the ACS controls from scratch with pci_enable_acs().
> 
> This makes ACS symmetric with the rest of a device's saved state. Today
> pci_save_state() ignores ACS entirely and pci_restore_state() re-enables
> the ACS controls from the kernel's current ACS policy. As a result, a
> device can come out of a reset with different ACS controls than it went
> in with, e.g. any controls programmed outside of pci_enable_acs() are
> silently dropped.
> 
> Notably, this prepares the kernel to be able to adopt the ACS controls
> established by a previous kernel across a Live Update rather than
> assigning new ones through pci_enable_acs().
> 
> [ ... ]
> configuring ACS from scratch for them. Do the same for devices that have
> no saved ACS state at all.
> 
> Assisted-by: LLM
> Signed-off-by: David Matlack <dmatlack at google.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261013162529.1928093-1-dmatlack@google.com?part=8