KVM: Remove irq_pending bitmap

Only one interrupt vector can be injected from userspace irqchip at
any given time so no need to store it in a bitmap. Put it into interrupt
queue directly.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

4 files changed, 13 insertions, 43 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 16d1481aa231..977a785a9d75 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -266,8 +266,6 @@ struct kvm_mmu {
 
 struct kvm_vcpu_arch {
         u64 host_tsc;
-        unsigned long irq_summary; /* bit vector: 1 per word in irq_pending */
-        DECLARE_BITMAP(irq_pending, KVM_NR_INTERRUPTS);
         /*
          * rip and regs accesses must go through
          * kvm_{register,rip}_{read,write} functions.
diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index 11c2757b808f..96dfbb6ad2a9 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -50,7 +50,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
         struct kvm_pic *s;
 
         if (!irqchip_in_kernel(v->kvm))
-                return v->arch.irq_summary;
+                return v->arch.interrupt.pending;
 
         if (kvm_apic_has_interrupt(v) == -1) {  /* LAPIC */
                 if (kvm_apic_accept_pic_intr(v)) {
@@ -72,7 +72,7 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
         int vector;
 
         if (!irqchip_in_kernel(v->kvm))
-                return kvm_pop_irq(v);
+                return v->arch.interrupt.nr;
 
         vector = kvm_get_apic_interrupt(v);     /* APIC */
         if (vector == -1) {
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 96413f4e33ba..54eec3565485 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1441,8 +1441,7 @@ static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
                 return -ENXIO;
         vcpu_load(vcpu);
 
-        set_bit(irq->irq, vcpu->arch.irq_pending);
-        set_bit(irq->irq / BITS_PER_LONG, &vcpu->arch.irq_summary);
+        kvm_queue_interrupt(vcpu, irq->irq);
 
         vcpu_put(vcpu);
 
@@ -3583,12 +3582,7 @@ int kvm_arch_vcpu_ioctl_get_sregs(struct kvm_vcpu *vcpu,
         sregs->efer = vcpu->arch.shadow_efer;
         sregs->apic_base = kvm_get_apic_base(vcpu);
 
-        if (irqchip_in_kernel(vcpu->kvm))
-                memset(sregs->interrupt_bitmap, 0,
-                       sizeof sregs->interrupt_bitmap);
-        else
-                memcpy(sregs->interrupt_bitmap, vcpu->arch.irq_pending,
-                       sizeof sregs->interrupt_bitmap);
+        memset(sregs->interrupt_bitmap, 0, sizeof sregs->interrupt_bitmap);
 
         if (vcpu->arch.interrupt.pending)
                 set_bit(vcpu->arch.interrupt.nr,
@@ -4058,7 +4052,7 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
                                   struct kvm_sregs *sregs)
 {
         int mmu_reset_needed = 0;
-        int i, pending_vec, max_bits;
+        int pending_vec, max_bits;
         struct descriptor_table dt;
 
         vcpu_load(vcpu);
@@ -4100,24 +4094,14 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu,
         if (mmu_reset_needed)
                 kvm_mmu_reset_context(vcpu);
 
-        if (!irqchip_in_kernel(vcpu->kvm)) {
-                memcpy(vcpu->arch.irq_pending, sregs->interrupt_bitmap,
-                       sizeof vcpu->arch.irq_pending);
-                vcpu->arch.irq_summary = 0;
-                for (i = 0; i < ARRAY_SIZE(vcpu->arch.irq_pending); ++i)
-                        if (vcpu->arch.irq_pending[i])
-                                __set_bit(i, &vcpu->arch.irq_summary);
-        } else {
-                max_bits = (sizeof sregs->interrupt_bitmap) << 3;
-                pending_vec = find_first_bit(
-                        (const unsigned long *)sregs->interrupt_bitmap,
-                        max_bits);
-                /* Only pending external irq is handled here */
-                if (pending_vec < max_bits) {
-                        kvm_queue_interrupt(vcpu, pending_vec);
-                        pr_debug("Set back pending irq %d\n", pending_vec);
-                }
-                kvm_pic_clear_isr_ack(vcpu->kvm);
+        max_bits = (sizeof sregs->interrupt_bitmap) << 3;
+        pending_vec = find_first_bit(
+                (const unsigned long *)sregs->interrupt_bitmap, max_bits);
+        if (pending_vec < max_bits) {
+                kvm_queue_interrupt(vcpu, pending_vec);
+                pr_debug("Set back pending irq %d\n", pending_vec);
+                if (irqchip_in_kernel(vcpu->kvm))
+                        kvm_pic_clear_isr_ack(vcpu->kvm);
         }
 
         kvm_set_segment(vcpu, &sregs->cs, VCPU_SREG_CS);
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 21203d421276..c1f1a8ceba64 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -19,18 +19,6 @@ static inline void kvm_clear_interrupt_queue(struct kvm_vcpu *vcpu)
         vcpu->arch.interrupt.pending = false;
 }
 
-static inline u8 kvm_pop_irq(struct kvm_vcpu *vcpu)
-{
-        int word_index = __ffs(vcpu->arch.irq_summary);
-        int bit_index = __ffs(vcpu->arch.irq_pending[word_index]);
-        int irq = word_index * BITS_PER_LONG + bit_index;
-
-        clear_bit(bit_index, &vcpu->arch.irq_pending[word_index]);
-        if (!vcpu->arch.irq_pending[word_index])
-                clear_bit(word_index, &vcpu->arch.irq_summary);
-        return irq;
-}
-
 static inline bool kvm_event_needs_reinjection(struct kvm_vcpu *vcpu)
 {
         return vcpu->arch.exception.pending || vcpu->arch.interrupt.pending ||