[PATCH v7 08/10] x86/nmi: Enable NMI-source for IPIs delivered as NMIs
From: Sohil Mehta <hidden>
Date: 2025-06-12 21:50:34
Also in:
kvm, linux-edac, linux-perf-users, linux-pm, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit), x86 mce infrastructure · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Tony Luck
With the IPI handling APIs ready to support the new NMI encoding, encode the NMI delivery mode directly with the NMI-source vectors to trigger NMIs. Move most of the existing NMI-based IPIs to use the new NMI-source vectors, except for the microcode rendezvous NMI and the crash reboot NMI. NMI handling for them is special-cased in exc_nmi() and does not need NMI-source reporting. However, in the future, it might be useful to assign a source vector to all NMI sources to improve isolation and debuggability. Originally-by: Jacob Pan [off-list ref] Suggested-by: Sean Christopherson <seanjc@google.com> Co-developed-by: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Xin Li (Intel) <xin@zytor.com> Signed-off-by: Sohil Mehta <redacted> --- v7: No change. v6: Include asm/nmi.h to avoid compile errors. (LKP) v5: Encode APIC_DM_NMI directly with the NMI-source vector. --- arch/x86/include/asm/apic.h | 8 ++++++++ arch/x86/kernel/apic/hw_nmi.c | 2 +- arch/x86/kernel/cpu/mce/inject.c | 2 +- arch/x86/kernel/kgdb.c | 2 +- arch/x86/kernel/nmi_selftest.c | 2 +- arch/x86/kernel/smp.c | 2 +- 6 files changed, 13 insertions(+), 5 deletions(-)
diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
index 32cdd81e5e45..5789df1708bd 100644
--- a/arch/x86/include/asm/apic.h
+++ b/arch/x86/include/asm/apic.h@@ -14,6 +14,7 @@ #include <asm/msr.h> #include <asm/hardirq.h> #include <asm/io.h> +#include <asm/nmi.h> #include <asm/posted_intr.h> #define ARCH_APICTIMER_STOPS_ON_C3 1
@@ -23,6 +24,13 @@ #define APIC_EXTNMI_ALL 1 #define APIC_EXTNMI_NONE 2 +/* Trigger NMIs with source information */ +#define TEST_NMI (APIC_DM_NMI | NMIS_VECTOR_TEST) +#define SMP_STOP_NMI (APIC_DM_NMI | NMIS_VECTOR_SMP_STOP) +#define BT_NMI (APIC_DM_NMI | NMIS_VECTOR_BT) +#define KGDB_NMI (APIC_DM_NMI | NMIS_VECTOR_KGDB) +#define MCE_NMI (APIC_DM_NMI | NMIS_VECTOR_MCE) + /* * Debugging macros */
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index 4e04f13d2de9..586f4b25feae 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c@@ -33,7 +33,7 @@ u64 hw_nmi_get_sample_period(int watchdog_thresh) #ifdef arch_trigger_cpumask_backtrace static void nmi_raise_cpu_backtrace(cpumask_t *mask) { - __apic_send_IPI_mask(mask, NMI_VECTOR); + __apic_send_IPI_mask(mask, BT_NMI); } void arch_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu)
diff --git a/arch/x86/kernel/cpu/mce/inject.c b/arch/x86/kernel/cpu/mce/inject.c
index 320068e01c22..81a04836ac74 100644
--- a/arch/x86/kernel/cpu/mce/inject.c
+++ b/arch/x86/kernel/cpu/mce/inject.c@@ -270,7 +270,7 @@ static void __maybe_unused raise_mce(struct mce *m) mce_irq_ipi, NULL, 0); preempt_enable(); } else if (m->inject_flags & MCJ_NMI_BROADCAST) - __apic_send_IPI_mask(mce_inject_cpumask, NMI_VECTOR); + __apic_send_IPI_mask(mce_inject_cpumask, MCE_NMI); } start = jiffies; while (!cpumask_empty(mce_inject_cpumask)) {
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index dfde434d2992..013feeb6a9ef 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c@@ -416,7 +416,7 @@ static void kgdb_disable_hw_debug(struct pt_regs *regs) */ void kgdb_roundup_cpus(void) { - apic_send_IPI_allbutself(NMI_VECTOR); + apic_send_IPI_allbutself(KGDB_NMI); } #endif
diff --git a/arch/x86/kernel/nmi_selftest.c b/arch/x86/kernel/nmi_selftest.c
index f3918888e494..d5578370b47f 100644
--- a/arch/x86/kernel/nmi_selftest.c
+++ b/arch/x86/kernel/nmi_selftest.c@@ -72,7 +72,7 @@ static void __init test_nmi_ipi(struct cpumask *mask) /* sync above data before sending NMI */ wmb(); - __apic_send_IPI_mask(mask, NMI_VECTOR); + __apic_send_IPI_mask(mask, TEST_NMI); /* Don't wait longer than a second */ timeout = USEC_PER_SEC;
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 1ed065b78467..239e9bf97abb 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c@@ -217,7 +217,7 @@ static void native_stop_other_cpus(int wait) pr_emerg("Shutting down cpus with NMI\n"); for_each_cpu(cpu, &cpus_stop_mask) - __apic_send_IPI(cpu, NMI_VECTOR); + __apic_send_IPI(cpu, SMP_STOP_NMI); } /* * Don't wait longer than 10 ms if the caller didn't
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2.43.0