KVM: Fix guest shared interrupt with in-kernel irqchip

Every call of kvm_set_irq() should offer an irq_source_id, which is
allocated by kvm_request_irq_source_id(). Based on irq_source_id, we
identify the irq source and implement logical OR for shared level
interrupts.

The allocated irq_source_id can be freed by kvm_free_irq_source_id().

Currently, we support at most sizeof(unsigned long) different irq sources.

[Amit: - rebase to kvm.git HEAD
       - move definition of KVM_USERSPACE_IRQ_SOURCE_ID to common file
       - move kvm_request_irq_source_id to the update_irq ioctl]

[Xiantao: - Add kvm/ia64 stuff and make it work for kvm/ia64 guests]

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
Signed-off-by: Amit Shah <amit.shah@redhat.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

4 files changed, 18 insertions, 3 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 65679d006337..8346be87cfa1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -364,6 +364,9 @@ struct kvm_arch{
 
         struct page *ept_identity_pagetable;
         bool ept_identity_pagetable_done;
+
+        unsigned long irq_sources_bitmap;
+        unsigned long irq_states[KVM_IOAPIC_NUM_PINS];
 };
 
 struct kvm_vm_stat {
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 11c6725fb798..8772dc946823 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -545,6 +545,12 @@ struct kvm_pit *kvm_create_pit(struct kvm *kvm)
         if (!pit)
                 return NULL;
 
+        mutex_lock(&kvm->lock);
+        pit->irq_source_id = kvm_request_irq_source_id(kvm);
+        mutex_unlock(&kvm->lock);
+        if (pit->irq_source_id < 0)
+                return NULL;
+
         mutex_init(&pit->pit_state.lock);
         mutex_lock(&pit->pit_state.lock);
         spin_lock_init(&pit->pit_state.inject_lock);
@@ -587,6 +593,7 @@ void kvm_free_pit(struct kvm *kvm)
                 mutex_lock(&kvm->arch.vpit->pit_state.lock);
                 timer = &kvm->arch.vpit->pit_state.pit_timer.timer;
                 hrtimer_cancel(timer);
+                kvm_free_irq_source_id(kvm, kvm->arch.vpit->irq_source_id);
                 mutex_unlock(&kvm->arch.vpit->pit_state.lock);
                 kfree(kvm->arch.vpit);
         }
@@ -595,8 +602,8 @@ void kvm_free_pit(struct kvm *kvm)
 static void __inject_pit_timer_intr(struct kvm *kvm)
 {
         mutex_lock(&kvm->lock);
-        kvm_set_irq(kvm, 0, 1);
-        kvm_set_irq(kvm, 0, 0);
+        kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 1);
+        kvm_set_irq(kvm, kvm->arch.vpit->irq_source_id, 0, 0);
         mutex_unlock(&kvm->lock);
 }
 
diff --git a/arch/x86/kvm/i8254.h b/arch/x86/kvm/i8254.h
index e436d4983aa1..4178022b97aa 100644
--- a/arch/x86/kvm/i8254.h
+++ b/arch/x86/kvm/i8254.h
@@ -44,6 +44,7 @@ struct kvm_pit {
         struct kvm_io_device speaker_dev;
         struct kvm *kvm;
         struct kvm_kpit_state pit_state;
+        int irq_source_id;
 };
 
 #define KVM_PIT_BASE_ADDRESS        0x40
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4f0677d1eae8..f1f8ff2f1fa2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1742,7 +1742,8 @@ long kvm_arch_vm_ioctl(struct file *filp,
                         goto out;
                 if (irqchip_in_kernel(kvm)) {
                         mutex_lock(&kvm->lock);
-                        kvm_set_irq(kvm, irq_event.irq, irq_event.level);
+                        kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID,
+                                    irq_event.irq, irq_event.level);
                         mutex_unlock(&kvm->lock);
                         r = 0;
                 }
@@ -4013,6 +4014,9 @@ struct  kvm *kvm_arch_create_vm(void)
         INIT_LIST_HEAD(&kvm->arch.active_mmu_pages);
         INIT_LIST_HEAD(&kvm->arch.assigned_dev_head);
 
+        /* Reserve bit 0 of irq_sources_bitmap for userspace irq source */
+        set_bit(KVM_USERSPACE_IRQ_SOURCE_ID, &kvm->arch.irq_sources_bitmap);
+
         return kvm;
 }