linux-kernel - [PATCH v3] x86/mm: Don't disable INVLPG if "incomplete Global INVLPG flushes" is fixed by microcode

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Date: Tue, 26 Mar 2024 05:28:18 +0800
From: Xi Ruoyao <xry111@...111.site>
To: Dave Hansen <dave.hansen@...ux.intel.com>,
	Michael Kelley <mhklinux@...look.com>
Cc: Andy Lutomirski <luto@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	x86@...nel.org,
	linux-kernel@...r.kernel.org,
	Xi Ruoyao <xry111@...111.site>
Subject: [PATCH v3] x86/mm: Don't disable INVLPG if "incomplete Global INVLPG flushes" is fixed by microcode

Per the "Processor Specification Update" documentations referred by the
intel-microcode-20240312 release note, this microcode release has fixed
the issue for all affected models.

So don't disable INVLPG if the microcode is new enough.

Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Link: https://lore.kernel.org/all/168436059559.404.13934972543631851306.tip-bot2@tip-bot2/
Link: https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/releases/tag/microcode-20240312
Link: https://cdrdv2.intel.com/v1/dl/getContent/740518 # RPL042, rev. 13
Link: https://cdrdv2.intel.com/v1/dl/getContent/682436 # ADL063, rev. 24
Signed-off-by: Xi Ruoyao <xry111@...111.site>
---
 arch/x86/mm/init.c | 37 +++++++++++++++++++++++++------------
 1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c
index 679893ea5e68..1a7d6a61a4cb 100644
--- a/arch/x86/mm/init.c
+++ b/arch/x86/mm/init.c
@@ -261,33 +261,46 @@ static void __init probe_page_size_mask(void)
 	}
 }
 
-#define INTEL_MATCH(_model) { .vendor  = X86_VENDOR_INTEL,	\
-			      .family  = 6,			\
-			      .model = _model,			\
-			    }
+#define INTEL_MATCH(_model, _fixed_microcode)	\
+    { .vendor		= X86_VENDOR_INTEL,	\
+      .family		= 6,			\
+      .model		= _model,		\
+      .driver_data	= _fixed_microcode,	\
+    }
+
 /*
  * INVLPG may not properly flush Global entries
- * on these CPUs when PCIDs are enabled.
+ * on these CPUs when PCIDs are enabled and the
+ * microcode is not updated to fix the issue.
  */
 static const struct x86_cpu_id invlpg_miss_ids[] = {
-	INTEL_MATCH(INTEL_FAM6_ALDERLAKE   ),
-	INTEL_MATCH(INTEL_FAM6_ALDERLAKE_L ),
-	INTEL_MATCH(INTEL_FAM6_ATOM_GRACEMONT ),
-	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE  ),
-	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_P),
-	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_S),
+	INTEL_MATCH(INTEL_FAM6_ALDERLAKE,	0x34),
+	INTEL_MATCH(INTEL_FAM6_ALDERLAKE_L,	0x432),
+	INTEL_MATCH(INTEL_FAM6_ATOM_GRACEMONT,	0x15),
+	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE,	0x122),
+	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_P,	0x4121),
+	INTEL_MATCH(INTEL_FAM6_RAPTORLAKE_S,	0x34),
 	{}
 };
 
 static void setup_pcid(void)
 {
+	const struct x86_cpu_id *invlpg_miss_match;
+
 	if (!IS_ENABLED(CONFIG_X86_64))
 		return;
 
 	if (!boot_cpu_has(X86_FEATURE_PCID))
 		return;
 
-	if (x86_match_cpu(invlpg_miss_ids)) {
+	invlpg_miss_match = x86_match_cpu(invlpg_miss_ids);
+
+	/* The hypervisor may lie about the microcode revision, conservatively
+	 * consider the microcode not updated.
+	 */
+	if (invlpg_miss_match &&
+	    (boot_cpu_has (X86_FEATURE_HYPERVISOR) ||
+	     invlpg_miss_match->driver_data > boot_cpu_data.microcode)) {
 		pr_info("Incomplete global flushes, disabling PCID");
 		setup_clear_cpu_cap(X86_FEATURE_PCID);
 		return;
-- 
2.44.0