From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
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 <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Sneddon <daniel.sneddon@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/intel-family.h | 5 +++++
arch/x86/mm/init.c | 25 +++++++++++++++++++++++++
2 files changed, 30 insertions(+)
diff --git a/arch/x86/include/asm/intel-family.h b/arch/x86/include/asm/intel-family.h
index 7811d42e78ef7..436ab2c3a4371 100644
--- a/arch/x86/include/asm/intel-family.h
+++ b/arch/x86/include/asm/intel-family.h
@@ -73,6 +73,11 @@
#define INTEL_FAM6_LAKEFIELD 0x8A
#define INTEL_FAM6_ALDERLAKE 0x97
#define INTEL_FAM6_ALDERLAKE_L 0x9A
+#define INTEL_FAM6_ALDERLAKE_N 0xBE
+
+#define INTEL_FAM6_RAPTORLAKE 0xB7
+#define INTEL_FAM6_RAPTORLAKE_P 0xBA
+#define INTEL_FAM6_RAPTORLAKE_S 0xBF
#define INTEL_FAM6_TIGERLAKE_L 0x8C
#define INTEL_FAM6_TIGERLAKE 0x8D
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 8039a951db8f5..579f48ee03be2 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -8,6 +8,7 @@
#include <linux/swapops.h>
#include <asm/set_memory.h>
+#include <asm/cpu_device_id.h>
#include <asm/e820/api.h>
#include <asm/init.h>
#include <asm/page.h>
@@ -199,6 +200,24 @@ 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))
@@ -207,6 +226,12 @@ 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
--
2.25.1
