On Tue, May 02, 2023 at 02:09:15PM +0200, Juergen Gross wrote: > This series tries to fix the rather special case of PAT being available > without having MTRRs (either due to CONFIG_MTRR being not set, or > because the feature has been disabled e.g. by a hypervisor). More weird stuff. With the series: [root@vh: ~> cat /proc/mtrr cat: /proc/mtrr: Input/output error before: [root@vh: ~> cat /proc/mtrr reg00: base=0x000000000 ( 0MB), size= 2048MB, count=1: write-back reg01: base=0x080000000 ( 2048MB), size= 1024MB, count=1: write-back reg02: base=0x0c0000000 ( 3072MB), size= 256MB, count=1: write-back reg03: base=0x0ff000000 ( 4080MB), size= 16MB, count=1: write-protect I think it wrongly determines that MTRRs are disabled by BIOS: MTRRs disabled by BIOS x86/PAT: Configuration [0-7]: WB WC UC- UC WB WP UC- WT which is obviously wrong. But more debugging later. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette