KVM: x86: Open code setting/clearing of bits in the ISR

Remove __apic_test_and_set_vector() and __apic_test_and_clear_vector(),
because the _only_ register that's safe to modify with a non-atomic
operation is ISR, because KVM isn't running the vCPU, i.e. hardware can't
service an IRQ or process an EOI for the relevant (virtual) APIC.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Neeraj Upadhyay <Neeraj.Upadhyay@amd.com>
Acked-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250709033242.267892-2-Neeraj.Upadhyay@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 73418dc0ebb223a49df8c06df242c7b7fcd9cb9e..013e8681247fdc58d2baa8925827aa62f1e4a9d7 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -125,16 +125,6 @@ bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector)
                apic_test_vector(vector, apic->regs + APIC_IRR);
 }
 
-static inline int __apic_test_and_set_vector(int vec, void *bitmap)
-{
-       return __test_and_set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
-}
-
-static inline int __apic_test_and_clear_vector(int vec, void *bitmap)
-{
-       return __test_and_clear_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
-}
-
 __read_mostly DEFINE_STATIC_KEY_FALSE(kvm_has_noapic_vcpu);
 EXPORT_SYMBOL_GPL(kvm_has_noapic_vcpu);
 
@@ -744,9 +734,14 @@ void kvm_apic_clear_irr(struct kvm_vcpu *vcpu, int vec)
 }
 EXPORT_SYMBOL_GPL(kvm_apic_clear_irr);
 
+static void *apic_vector_to_isr(int vec, struct kvm_lapic *apic)
+{
+       return apic->regs + APIC_ISR + REG_POS(vec);
+}
+
 static inline void apic_set_isr(int vec, struct kvm_lapic *apic)
 {
-       if (__apic_test_and_set_vector(vec, apic->regs + APIC_ISR))
+       if (__test_and_set_bit(VEC_POS(vec), apic_vector_to_isr(vec, apic)))
                return;
 
        /*
@@ -789,7 +784,7 @@ static inline int apic_find_highest_isr(struct kvm_lapic *apic)
 
 static inline void apic_clear_isr(int vec, struct kvm_lapic *apic)
 {
-       if (!__apic_test_and_clear_vector(vec, apic->regs + APIC_ISR))
+       if (!__test_and_clear_bit(VEC_POS(vec), apic_vector_to_isr(vec, apic)))
                return;
 
        /*