x86/mm: Add INVLPGB feature and Kconfig entry

In addition, the CPU advertises the maximum number of pages that can be shot down with one INVLPGB instruction in CPUID. Save that information for later use. [ bp: use cpu_has(), typos, massage. ] Signed-off-by: Rik van Riel <riel@surriel.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20250226030129.530345-3-riel@surriel.com
mariux64 · Mar 19, 2025 · 767ae43 · 767ae43
1 parent 4a02ed8
commit 767ae43
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Showing 5 changed files with 21 additions and 1 deletion.
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
@@ -334,6 +334,10 @@ menuconfig PROCESSOR_SELECT
 	  This lets you choose what x86 vendor support code your kernel
 	  will include.
 
+config BROADCAST_TLB_FLUSH
+	def_bool y
+	depends on CPU_SUP_AMD && 64BIT
+
 config CPU_SUP_INTEL
 	default y
 	bool "Support Intel processors" if PROCESSOR_SELECT

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
@@ -338,6 +338,7 @@
 #define X86_FEATURE_CLZERO		(13*32+ 0) /* "clzero" CLZERO instruction */
 #define X86_FEATURE_IRPERF		(13*32+ 1) /* "irperf" Instructions Retired Count */
 #define X86_FEATURE_XSAVEERPTR		(13*32+ 2) /* "xsaveerptr" Always save/restore FP error pointers */
+#define X86_FEATURE_INVLPGB		(13*32+ 3) /* INVLPGB and TLBSYNC instructions supported */
 #define X86_FEATURE_RDPRU		(13*32+ 4) /* "rdpru" Read processor register at user level */
 #define X86_FEATURE_WBNOINVD		(13*32+ 9) /* "wbnoinvd" WBNOINVD instruction */
 #define X86_FEATURE_AMD_IBPB		(13*32+12) /* Indirect Branch Prediction Barrier */

diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
@@ -129,6 +129,12 @@
 #define DISABLE_SEV_SNP		(1 << (X86_FEATURE_SEV_SNP & 31))
 #endif
 
+#ifdef CONFIG_BROADCAST_TLB_FLUSH
+#define DISABLE_INVLPGB		0
+#else
+#define DISABLE_INVLPGB		(1 << (X86_FEATURE_INVLPGB & 31))
+#endif
+
 /*
  * Make sure to add features to the correct mask
  */
@@ -146,7 +152,7 @@
 #define DISABLED_MASK11	(DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
 			 DISABLE_CALL_DEPTH_TRACKING|DISABLE_USER_SHSTK)
 #define DISABLED_MASK12	(DISABLE_FRED|DISABLE_LAM)
-#define DISABLED_MASK13	0
+#define DISABLED_MASK13	(DISABLE_INVLPGB)
 #define DISABLED_MASK14	0
 #define DISABLED_MASK15	0
 #define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \

diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
@@ -183,6 +183,9 @@ static inline void cr4_init_shadow(void)
 extern unsigned long mmu_cr4_features;
 extern u32 *trampoline_cr4_features;
 
+/* How many pages can be invalidated with one INVLPGB. */
+extern u16 invlpgb_count_max;
+
 extern void initialize_tlbstate_and_flush(void);
 
 /*

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
@@ -29,6 +29,8 @@
 
 #include "cpu.h"
 
+u16 invlpgb_count_max __ro_after_init;
+
 static inline int rdmsrl_amd_safe(unsigned msr, unsigned long long *p)
 {
 	u32 gprs[8] = { 0 };
@@ -1139,6 +1141,10 @@ static void cpu_detect_tlb_amd(struct cpuinfo_x86 *c)
 		tlb_lli_2m = eax & mask;
 
 	tlb_lli_4m = tlb_lli_2m >> 1;
+
+	/* Max number of pages INVLPGB can invalidate in one shot */
+	if (cpu_has(c, X86_FEATURE_INVLPGB))
+		invlpgb_count_max = (cpuid_edx(0x80000008) & 0xffff) + 1;
 }
 
 static const struct cpu_dev amd_cpu_dev = {