On Wed, Nov 02, 2022 at 08:46:57AM +0100, Juergen Gross wrote:
Today PAT can't be used without MTRR being available, unless MTRR is at
least configured via CONFIG_MTRR and the system is running as Xen PV
guest. In this case PAT is automatically available via the hypervisor,
but the PAT MSR can't be modified by the kernel and MTRR is disabled.
The same applies to a kernel built with no MTRR support: it won't
allow to use the PAT MSR, even if there is no technical reason for
that, other than setting up PAT on all CPUs the same way (which is a
requirement of the processor's cache management) is relying on some
MTRR specific code.
Fix all of that by:
One of the AMD test boxes here says with this:
...
[ 0.863466] PCI: not using MMCONFIG
[ 0.863475] PCI: Using configuration type 1 for base access
[ 0.863478] PCI: Using configuration type 1 for extended access
[ 0.866733] mtrr: your CPUs had inconsistent MTRRdefType settings
[ 0.866737] mtrr: probably your BIOS does not setup all CPUs.
[ 0.866740] mtrr: corrected configuration.
[ 0.869350] kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible.
...
Previous logs don't have it:
PCI: not using MMCONFIG
PCI: Using configuration type 1 for base access
PCI: Using configuration type 1 for extended access
kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible.
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