diff --git a/include/kvm/virtio.h b/include/kvm/virtio.h
index 3880e74..ad274ac 100644
--- a/include/kvm/virtio.h
+++ b/include/kvm/virtio.h
@@ -187,7 +187,7 @@ struct virtio_ops {
 	size_t (*get_config_size)(struct kvm *kvm, void *dev);
 	u32 (*get_host_features)(struct kvm *kvm, void *dev);
 	void (*set_guest_features)(struct kvm *kvm, void *dev, u32 features);
-	int (*get_vq_count)(struct kvm *kvm, void *dev);
+	unsigned int (*get_vq_count)(struct kvm *kvm, void *dev);
 	int (*init_vq)(struct kvm *kvm, void *dev, u32 vq, u32 page_size,
 		       u32 align, u32 pfn);
 	void (*exit_vq)(struct kvm *kvm, void *dev, u32 vq);
diff --git a/virtio/9p.c b/virtio/9p.c
index 6074f3a..7374f1e 100644
--- a/virtio/9p.c
+++ b/virtio/9p.c
@@ -1469,7 +1469,7 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return NUM_VIRT_QUEUES;
 }
diff --git a/virtio/balloon.c b/virtio/balloon.c
index 5bcd6ab..450b36a 100644
--- a/virtio/balloon.c
+++ b/virtio/balloon.c
@@ -251,7 +251,7 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return NUM_VIRT_QUEUES;
 }
diff --git a/virtio/blk.c b/virtio/blk.c
index af71c0c..46ee028 100644
--- a/virtio/blk.c
+++ b/virtio/blk.c
@@ -291,7 +291,7 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return NUM_VIRT_QUEUES;
 }
diff --git a/virtio/console.c b/virtio/console.c
index dae6034..8315808 100644
--- a/virtio/console.c
+++ b/virtio/console.c
@@ -216,7 +216,7 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return VIRTIO_CONSOLE_NUM_QUEUES;
 }
diff --git a/virtio/mmio.c b/virtio/mmio.c
index 0094856..d3555b4 100644
--- a/virtio/mmio.c
+++ b/virtio/mmio.c
@@ -175,13 +175,22 @@ static void virtio_mmio_config_out(struct kvm_cpu *vcpu,
 {
 	struct virtio_mmio *vmmio = vdev->virtio;
 	struct kvm *kvm = vmmio->kvm;
+	unsigned int vq_count = vdev->ops->get_vq_count(kvm, vmmio->dev);
 	u32 val = 0;
 
 	switch (addr) {
 	case VIRTIO_MMIO_HOST_FEATURES_SEL:
 	case VIRTIO_MMIO_GUEST_FEATURES_SEL:
+		val = ioport__read32(data);
+		*(u32 *)(((void *)&vmmio->hdr) + addr) = val;
+		break;
 	case VIRTIO_MMIO_QUEUE_SEL:
 		val = ioport__read32(data);
+		if (val >= vq_count) {
+			WARN_ONCE(1, "QUEUE_SEL value (%u) is larger than VQ count (%u)\n",
+				val, vq_count);
+			break;
+		}
 		*(u32 *)(((void *)&vmmio->hdr) + addr) = val;
 		break;
 	case VIRTIO_MMIO_STATUS:
@@ -227,6 +236,11 @@ static void virtio_mmio_config_out(struct kvm_cpu *vcpu,
 		break;
 	case VIRTIO_MMIO_QUEUE_NOTIFY:
 		val = ioport__read32(data);
+		if (val >= vq_count) {
+			WARN_ONCE(1, "QUEUE_NOTIFY value (%u) is larger than VQ count (%u)\n",
+				val, vq_count);
+			break;
+		}
 		vdev->ops->notify_vq(vmmio->kvm, vmmio->dev, val);
 		break;
 	case VIRTIO_MMIO_INTERRUPT_ACK:
@@ -346,10 +360,12 @@ int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 
 int virtio_mmio_reset(struct kvm *kvm, struct virtio_device *vdev)
 {
-	int vq;
+	unsigned int vq;
 	struct virtio_mmio *vmmio = vdev->virtio;
+	unsigned int vq_count;
 
-	for (vq = 0; vq < vdev->ops->get_vq_count(kvm, vmmio->dev); vq++)
+	vq_count = vdev->ops->get_vq_count(kvm, vmmio->dev);
+	for (vq = 0; vq < vq_count; vq++)
 		virtio_mmio_exit_vq(kvm, vdev, vq);
 
 	return 0;
diff --git a/virtio/net.c b/virtio/net.c
index ec5dc1f..8dd523f 100644
--- a/virtio/net.c
+++ b/virtio/net.c
@@ -755,11 +755,11 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	struct net_dev *ndev = dev;
 
-	return ndev->queue_pairs * 2 + 1;
+	return ndev->queue_pairs * 2U + 1U;
 }
 
 static struct virtio_ops net_dev_virtio_ops = {
diff --git a/virtio/pci.c b/virtio/pci.c
index 0b5cccd..9a6cbf3 100644
--- a/virtio/pci.c
+++ b/virtio/pci.c
@@ -329,9 +329,11 @@ static bool virtio_pci__data_out(struct kvm_cpu *vcpu, struct virtio_device *vde
 	struct virtio_pci *vpci;
 	struct kvm *kvm;
 	u32 val;
+	unsigned int vq_count;
 
 	kvm = vcpu->kvm;
 	vpci = vdev->virtio;
+	vq_count = vdev->ops->get_vq_count(kvm, vpci->dev);
 
 	switch (offset) {
 	case VIRTIO_PCI_GUEST_FEATURES:
@@ -351,10 +353,21 @@ static bool virtio_pci__data_out(struct kvm_cpu *vcpu, struct virtio_device *vde
 		}
 		break;
 	case VIRTIO_PCI_QUEUE_SEL:
-		vpci->queue_selector = ioport__read16(data);
+		val = ioport__read16(data);
+		if (val >= vq_count) {
+			WARN_ONCE(1, "QUEUE_SEL value (%u) is larger than VQ count (%u)\n",
+				val, vq_count);
+			return false;
+		}
+		vpci->queue_selector = val;
 		break;
 	case VIRTIO_PCI_QUEUE_NOTIFY:
 		val = ioport__read16(data);
+		if (val >= vq_count) {
+			WARN_ONCE(1, "QUEUE_SEL value (%u) is larger than VQ count (%u)\n",
+				val, vq_count);
+			return false;
+		}
 		vdev->ops->notify_vq(kvm, vpci->dev, val);
 		break;
 	case VIRTIO_PCI_STATUS:
@@ -647,10 +660,12 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 
 int virtio_pci__reset(struct kvm *kvm, struct virtio_device *vdev)
 {
-	int vq;
+	unsigned int vq;
+	unsigned int vq_count;
 	struct virtio_pci *vpci = vdev->virtio;
 
-	for (vq = 0; vq < vdev->ops->get_vq_count(kvm, vpci->dev); vq++)
+	vq_count = vdev->ops->get_vq_count(kvm, vpci->dev);
+	for (vq = 0; vq < vq_count; vq++)
 		virtio_pci_exit_vq(kvm, vdev, vq);
 
 	return 0;
diff --git a/virtio/rng.c b/virtio/rng.c
index c7835a0..75b682e 100644
--- a/virtio/rng.c
+++ b/virtio/rng.c
@@ -147,7 +147,7 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return NUM_VIRT_QUEUES;
 }
diff --git a/virtio/scsi.c b/virtio/scsi.c
index 8f1c348..60432cc 100644
--- a/virtio/scsi.c
+++ b/virtio/scsi.c
@@ -176,7 +176,7 @@ static int set_size_vq(struct kvm *kvm, void *dev, u32 vq, int size)
 	return size;
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return NUM_VIRT_QUEUES;
 }
diff --git a/virtio/vsock.c b/virtio/vsock.c
index 34397b6..64b4e95 100644
--- a/virtio/vsock.c
+++ b/virtio/vsock.c
@@ -204,7 +204,7 @@ static void notify_vq_gsi(struct kvm *kvm, void *dev, u32 vq, u32 gsi)
 		die_perror("VHOST_SET_VRING_CALL failed");
 }
 
-static int get_vq_count(struct kvm *kvm, void *dev)
+static unsigned int get_vq_count(struct kvm *kvm, void *dev)
 {
 	return VSOCK_VQ_MAX;
 }
