[PATCH 02/10] x86,tlb: get INVLPGB count max from CPUID

[Rik van Riel]

The CPU advertises the maximum number of pages that can be shot down
with one INVLPGB instruction in the CPUID data.

Save that information for later use.

Signed-off-by: Rik van Riel <riel@xxxxxxxxxxx>
---
 arch/x86/include/asm/processor.h | 2 ++
 arch/x86/kernel/cpu/amd.c        | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 20e6009381ed..dd32a75d5da8 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -185,6 +185,8 @@ struct cpuinfo_x86 {
 	u16			booted_cores;
 	/* Index into per_cpu list: */
 	u16			cpu_index;
+	/* Max number of pages invalidated with one INVLPGB */
+	u16			invlpgb_count_max;
 	/*  Is SMT active on this core? */
 	bool			smt_active;
 	u32			microcode;
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 79d2e17f6582..6a6adbe9ae54 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -1135,6 +1135,14 @@ static void cpu_detect_tlb_amd(struct cpuinfo_x86 *c)
 		tlb_lli_2m[ENTRIES] = eax & mask;
 
 	tlb_lli_4m[ENTRIES] = tlb_lli_2m[ENTRIES] >> 1;
+
+	if (c->extended_cpuid_level < 0x80000008)
+		return;
+
+	cpuid(0x80000008, &eax, &ebx, &ecx, &edx);
+
+	/* Max number of pages INVLPGB can invalidate in one shot */
+	c->invlpgb_count_max = (edx & 0xffff) + 1;
 }
 
 static const struct cpu_dev amd_cpu_dev = {
-- 
2.47.1