diff options
| author | Juergen Gross <jgross@suse.com> | 2022-11-02 08:47:10 +0100 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-11-10 13:12:45 +0100 |
| commit | adfe7512e1d0b2e83215b0ec56337d2df9f1032d (patch) | |
| tree | 1b7098e1bc66f88da331abff517161e9b5788d16 /arch/x86/kernel/cpu/mtrr | |
| parent | 0b9a6a8bedbfb38e7c6be4d119a267e6277307cc (diff) | |
x86: Decouple PAT and MTRR handling
Today, PAT is usable only with MTRR being active, with some nasty tweaks
to make PAT usable when running as a Xen PV guest which doesn't support
MTRR.
The reason for this coupling is that both PAT MSR changes and MTRR
changes require a similar sequence and so full PAT support was added
using the already available MTRR handling.
Xen PV PAT handling can work without MTRR, as it just needs to consume
the PAT MSR setting done by the hypervisor without the ability and need
to change it. This in turn has resulted in a convoluted initialization
sequence and wrong decisions regarding cache mode availability due to
misguiding PAT availability flags.
Fix all of that by allowing to use PAT without MTRR and by reworking
the current PAT initialization sequence to match better with the newly
introduced generic cache initialization.
This removes the need of the recently added pat_force_disabled flag, so
remove the remnants of the patch adding it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20221102074713.21493-14-jgross@suse.com
Signed-off-by: Borislav Petkov <bp@suse.de>
Diffstat (limited to 'arch/x86/kernel/cpu/mtrr')
| -rw-r--r-- | arch/x86/kernel/cpu/mtrr/mtrr.c | 12 |
1 files changed, 2 insertions, 10 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c index 99b6973a69b4..8403daf34158 100644 --- a/arch/x86/kernel/cpu/mtrr/mtrr.c +++ b/arch/x86/kernel/cpu/mtrr/mtrr.c @@ -725,7 +725,7 @@ void __init mtrr_bp_init(void) if (mtrr_if == &generic_mtrr_ops) { /* BIOS may override */ if (get_mtrr_state()) { - memory_caching_control |= CACHE_MTRR | CACHE_PAT; + memory_caching_control |= CACHE_MTRR; changed_by_mtrr_cleanup = mtrr_cleanup(phys_addr); } else { mtrr_if = NULL; @@ -733,16 +733,8 @@ void __init mtrr_bp_init(void) } } - if (!mtrr_enabled()) { + if (!mtrr_enabled()) pr_info("Disabled\n"); - - /* - * PAT initialization relies on MTRR's rendezvous handler. - * Skip PAT init until the handler can initialize both - * features independently. - */ - pat_disable("MTRRs disabled, skipping PAT initialization too."); - } } /** |