pc: kvm: check if KVM has free memory slots to avoid abort()

When more memory devices are used than available
KVM memory slots, QEMU crashes with:

kvm_alloc_slot: no free slot available
Aborted (core dumped)

Fix this by checking that KVM has a free slot before
attempting to map memory in guest address space.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/kvm-all.c b/kvm-all.c
index 596e7ce..937bc9d 100644
--- a/kvm-all.c
+++ b/kvm-all.c
@@ -132,7 +132,7 @@ static const KVMCapabilityInfo kvm_required_capabilites[] = {
     KVM_CAP_LAST_INFO
 };
 
-static KVMSlot *kvm_alloc_slot(KVMState *s)
+static KVMSlot *kvm_get_free_slot(KVMState *s)
 {
     int i;
 
@@ -142,6 +142,22 @@ static KVMSlot *kvm_alloc_slot(KVMState *s)
         }
     }
 
+    return NULL;
+}
+
+bool kvm_has_free_slot(MachineState *ms)
+{
+    return kvm_get_free_slot(KVM_STATE(ms->accelerator));
+}
+
+static KVMSlot *kvm_alloc_slot(KVMState *s)
+{
+    KVMSlot *slot = kvm_get_free_slot(s);
+
+    if (slot) {
+        return slot;
+    }
+
     fprintf(stderr, "%s: no free slot available\n", __func__);
     abort();
 }