Re: [PATCH v7 08/12] PCI: liveupdate: Inherit ACS flags in incoming preserved devices

[sashiko-bot@kernel.org]

> Inherit Access Control Services (ACS) flags on all incoming preserved
> devices (endpoints and upstream bridges) during a Live Update.
> 
> Inheriting ACS flags avoids changing routing rules while memory
> transactions are in flight from preserved devices. This is also strictly
> necessary to ensure that IOMMU group assignments do not change across
> a Live Update for preserved devices, as changing ACS configurations can
> split or merge IOMMU groups.
> 
> Cache the inherited ACS controls established by the previous kernel in
> struct pci_dev so that ACS controls do not change after a reset
> (pci_restore_state() calls pci_enable_acs()).
> 
> To simplify ACS inheritance, reject preserving any devices that require
> quirks to enable ACS as those quirks would also have to take Live Update
> into account.
> 
> Signed-off-by: David Matlack <dmatlack@google.com>

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

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