Support from AMD to add the ability to access the ACPI tables that provide the steering tags to use for each cache has been accepted in the upstream kernel, and merged in 6.13.
If you build the kernel manually enable CONFIG_PCIE_TPH before rebuilding and installing the kernel as normal.
You can check whether a kernel has CONFIG_PCIE_TPH enabled as follows:
grep CONFIG_PCIE_TPH /boot/config-$(uname -r)If you get the following output, CONFIG_PCIE_TPH is enabled:
CONFIG_PCIE_TPH=yAMD have actively worked with Linux distributions to include this support in the distribution kernels. Deb packages for Ubuntu with recent (6.13) kernels have CONFIG_PCIE_TPH already compiled in and are suitable for use. RHEL 9.7 and RHEL 10.1 also have CONFIG_PCIE_TPH already compiled in and are suitable for use.