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linux/debian/patches/patchset-pf/invlpgb/0004-x86-mm-get-INVLPGB-count-max-from-CPUID.patch
2025-01-02 21:18:06 +03:00

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1.7 KiB
Diff

From 98953e10e342ceea1dc877cfb63318fa85879a59 Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@surriel.com>
Date: Mon, 30 Dec 2024 12:53:05 -0500
Subject: x86/mm: get INVLPGB count max from CPUID
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@surriel.com>
---
arch/x86/include/asm/tlbflush.h | 1 +
arch/x86/kernel/cpu/amd.c | 8 ++++++++
arch/x86/kernel/setup.c | 4 ++++
3 files changed, 13 insertions(+)
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -182,6 +182,7 @@ static inline void cr4_init_shadow(void)
extern unsigned long mmu_cr4_features;
extern u32 *trampoline_cr4_features;
+extern u16 invlpgb_count_max;
extern void initialize_tlbstate_and_flush(void);
--- 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 cp
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 */
+ invlpgb_count_max = (edx & 0xffff) + 1;
}
static const struct cpu_dev amd_cpu_dev = {
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -138,6 +138,10 @@ __visible unsigned long mmu_cr4_features
__visible unsigned long mmu_cr4_features __ro_after_init = X86_CR4_PAE;
#endif
+#ifdef CONFIG_CPU_SUP_AMD
+u16 invlpgb_count_max __ro_after_init;
+#endif
+
#ifdef CONFIG_IMA
static phys_addr_t ima_kexec_buffer_phys;
static size_t ima_kexec_buffer_size;