From ac7f7555ac6519ce5077f9fd3e644eab5b806b7b Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Tue, 16 May 2023 12:24:25 -0700 Subject: [PATCH] x86/mm: Avoid incomplete Global INVLPG flushes commit ce0b15d11ad837fbacc5356941712218e38a0a83 upstream. The INVLPG instruction is used to invalidate TLB entries for a specified virtual address. When PCIDs are enabled, INVLPG is supposed to invalidate TLB entries for the specified address for both the current PCID *and* Global entries. (Note: Only kernel mappings set Global=1.) Unfortunately, some INVLPG implementations can leave Global translations unflushed when PCIDs are enabled. As a workaround, never enable PCIDs on affected processors. I expect there to eventually be microcode mitigations to replace this software workaround. However, the exact version numbers where that will happen are not known today. Once the version numbers are set in stone, the processor list can be tweaked to only disable PCIDs on affected processors with affected microcode. Note: if anyone wants a quick fix that doesn't require patching, just stick 'nopcid' on your kernel command-line. Signed-off-by: Dave Hansen Reviewed-by: Thomas Gleixner Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/init.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 9121bc1b9453a..0d5ccea2538fc 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -9,6 +9,7 @@ #include #include +#include #include #include #include @@ -260,6 +261,24 @@ static void __init probe_page_size_mask(void) } } +#define INTEL_MATCH(_model) { .vendor = X86_VENDOR_INTEL, \ + .family = 6, \ + .model = _model, \ + } +/* + * INVLPG may not properly flush Global entries + * on these CPUs when PCIDs are enabled. + */ +static const struct x86_cpu_id invlpg_miss_ids[] = { + INTEL_MATCH(INTEL_FAM6_ALDERLAKE ), + INTEL_MATCH(INTEL_FAM6_ALDERLAKE_L ), + INTEL_MATCH(INTEL_FAM6_ALDERLAKE_N ), + INTEL_MATCH(INTEL_FAM6_RAPTORLAKE ), + INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_P), + INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_S), + {} +}; + static void setup_pcid(void) { if (!IS_ENABLED(CONFIG_X86_64)) @@ -268,6 +287,12 @@ static void setup_pcid(void) if (!boot_cpu_has(X86_FEATURE_PCID)) return; + if (x86_match_cpu(invlpg_miss_ids)) { + pr_info("Incomplete global flushes, disabling PCID"); + setup_clear_cpu_cap(X86_FEATURE_PCID); + return; + } + if (boot_cpu_has(X86_FEATURE_PGE)) { /* * This can't be cr4_set_bits_and_update_boot() -- the -- 2.39.5