KVM: x86: flush pending lapic jump label updates on module unload

[ Upstream commit cef84c302fe051744b983a92764d3fcca933415d ]

KVM's lapic emulation uses static_key_deferred (apic_{hw,sw}_disabled).
These are implemented with delayed_work structs which can still be
pending when the KVM module is unloaded. We've seen this cause kernel
panics when the kvm_intel module is quickly reloaded.

Use the new static_key_deferred_flush() API to flush pending updates on
module unload.

Signed-off-by: David Matlack <dmatlack@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 7dd9a8d3911ae22fe12b105fe279fd6844b11f70..b9cf3ee6514f387bc096a1781443c63d4d8e5a41 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -2080,3 +2080,9 @@ void kvm_lapic_init(void)
        jump_label_rate_limit(&apic_hw_disabled, HZ);
        jump_label_rate_limit(&apic_sw_disabled, HZ);
 }
+
+void kvm_lapic_exit(void)
+{
+       static_key_deferred_flush(&apic_hw_disabled);
+       static_key_deferred_flush(&apic_sw_disabled);
+}

diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index c4ea87eedf8a71128b265efacf6f8fdc01b62dc2..5773f1eaf46e835ca9eb01d9b063637b81430bbb 100644 (file)
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -95,6 +95,7 @@ static inline bool kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu)
 
 int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data);
 void kvm_lapic_init(void);
+void kvm_lapic_exit(void);
 
 static inline u32 kvm_apic_get_reg(struct kvm_lapic *apic, int reg_off)
 {

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bd84d2226ca15c84bb1b02bb65e100f55b22a16d..1592e2986f7a6c2c2e354a6f3461d807e08aaa7a 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5848,6 +5848,7 @@ out:
 
 void kvm_arch_exit(void)
 {
+       kvm_lapic_exit();
        perf_unregister_guest_info_callbacks(&kvm_guest_cbs);
 
        if (!boot_cpu_has(X86_FEATURE_CONSTANT_TSC))