Re: [v9 PATCH 1/2] PCI/ACPI: Support Microsoft's "DmaProperty"

[Greg KH <gregkh@linuxfoundation.org>]

On Fri, Feb 21, 2025 at 12:09:40AM +0000, Joshua Peraza wrote:
> From: Rajat Jain <rajatja@google.com>
> 
> The "DmaProperty" is supported and currently documented and used by
> Microsoft [link 1 below], to flag internal PCIe root ports that need
> DMA protection [link 2 below]. We have discussed with them and reached
> a common understanding that they shall change their MSDN documentation
> to say that the same property can be used to protect any PCI device,
> and not just internal PCIe root ports (since there is no point
> introducing yet another property for arbitrary PCI devices). This helps
> with security from internal devices that offer an attack surface for
> DMA attacks (e.g. internal network devices).
> 
> Support DmaProperty to mark DMA from a PCI device as untrusted.
> 
> Link: [1] https://docs.microsoft.com/en-us/windows-hardware/drivers/pci/dsd-for-pcie-root-ports#identifying-internal-pcie-ports-accessible-to-users-and-requiring-dma-protection
> Link: [2] https://docs.microsoft.com/en-us/windows/security/information-protection/kernel-dma-protection-for-thunderbolt
> Signed-off-by: Rajat Jain <rajatja@google.com>
> Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Signed-off-by: Joshua Peraza <jperaza@google.com>
> ---
>  drivers/acpi/property.c |  3 +++
>  drivers/pci/pci-acpi.c  | 22 ++++++++++++++++++++++
>  2 files changed, 25 insertions(+)

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>