[PATCH 08/16] kvm: libkvm: allocate unused gsi for irq routing

[Sheng Yang <sheng@xxxxxxxxxxxxxxx>]

Notice here is a simple solution, can be replaced later.

(update: fix kvm_check_extension() only return 0 or 1, which is inconsisent
with kvm_get_gsi_count())

Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
---
 libkvm/kvm-common.h |    1 +
 libkvm/libkvm.c     |   17 ++++++++++++++++-
 libkvm/libkvm.h     |    8 ++++++++
 3 files changed, 25 insertions(+), 1 deletions(-)

diff --git a/libkvm/kvm-common.h b/libkvm/kvm-common.h
index de1ada2..70a95c2 100644
--- a/libkvm/kvm-common.h
+++ b/libkvm/kvm-common.h
@@ -66,6 +66,7 @@ struct kvm_context {
 #ifdef KVM_CAP_IRQ_ROUTING
 	struct kvm_irq_routing *irq_routes;
 	int nr_allocated_irq_routes;
+	int max_used_gsi;
 #endif
 };
 
diff --git a/libkvm/libkvm.c b/libkvm/libkvm.c
index e9bae23..d38ca00 100644
--- a/libkvm/libkvm.c
+++ b/libkvm/libkvm.c
@@ -421,7 +421,7 @@ int kvm_check_extension(kvm_context_t kvm, int ext)
 
 	ret = ioctl(kvm->fd, KVM_CHECK_EXTENSION, ext);
 	if (ret > 0)
-		return 1;
+		return ret;
 	return 0;
 }
 
@@ -1292,6 +1292,9 @@ int kvm_add_routing_entry(kvm_context_t kvm,
 	new->type = entry->type;
 	new->flags = entry->flags;
 	new->u = entry->u;
+
+	if (entry->gsi > kvm->max_used_gsi)
+		kvm->max_used_gsi = entry->gsi;
 	return 0;
 #else
 	return -ENOSYS;
@@ -1395,3 +1398,15 @@ int kvm_commit_irq_routes(kvm_context_t kvm)
 	return -ENOSYS;
 #endif
 }
+
+int kvm_get_irq_route_gsi(kvm_context_t kvm)
+{
+	if (kvm->max_used_gsi >= KVM_IOAPIC_NUM_PINS)  {
+	    if (kvm->max_used_gsi <= kvm_get_gsi_count(kvm)) 
+                return kvm->max_used_gsi + 1;
+            else
+                return -ENOSPC;
+        } else
+            return KVM_IOAPIC_NUM_PINS;
+}
+
diff --git a/libkvm/libkvm.h b/libkvm/libkvm.h
index 51f4d08..9a7cbc6 100644
--- a/libkvm/libkvm.h
+++ b/libkvm/libkvm.h
@@ -846,4 +846,12 @@ int kvm_del_routing_entry(kvm_context_t kvm,
  */
 int kvm_commit_irq_routes(kvm_context_t kvm);
 
+/*!
+ * \brief Get unused GSI number for irq routing table
+ *
+ * Get unused GSI number for irq routing table
+ *
+ * \param kvm Pointer to the current kvm_context
+ */
+int kvm_get_irq_route_gsi(kvm_context_t kvm);
 #endif
-- 
1.5.4.5

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