eni_vdpa: add vDPA driver for Alibaba ENI

This patch adds a new vDPA driver for Alibaba ENI(Elastic Network
Interface) which is build upon virtio 0.9.5 specification.
And this driver is only enabled on X86 host currently.

Link: https://lore.kernel.org/r/6a9f32c00609af16bbb2ea32e633b3beb1cbf84b.1635493219.git.wuzongyong@linux.alibaba.com
Signed-off-by: Wu Zongyong <wuzongyong@linux.alibaba.com>
Link: https://lore.kernel.org/r/20211026083214.3375383-1-arnd@kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de> # fix Kconfig typo
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

4 files changed, 565 insertions, 0 deletions

diff --git a/drivers/vdpa/Kconfig b/drivers/vdpa/Kconfig
index 3d91982d8371..50f45d037611 100644
--- a/drivers/vdpa/Kconfig
+++ b/drivers/vdpa/Kconfig
@@ -78,4 +78,12 @@ config VP_VDPA
 	help
 	  This kernel module bridges virtio PCI device to vDPA bus.
 
+config ALIBABA_ENI_VDPA
+	tristate "vDPA driver for Alibaba ENI"
+	select VIRTIO_PCI_LIB_LEGACY
+	depends on PCI_MSI && X86
+	help
+	  VDPA driver for Alibaba ENI (Elastic Network Interface) which is built upon
+	  virtio 0.9.5 specification.
+
 endif # VDPA
diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
index f02ebed33f19..15665563a7f4 100644
--- a/drivers/vdpa/Makefile
+++ b/drivers/vdpa/Makefile
@@ -5,3 +5,4 @@ obj-$(CONFIG_VDPA_USER) += vdpa_user/
 obj-$(CONFIG_IFCVF)    += ifcvf/
 obj-$(CONFIG_MLX5_VDPA) += mlx5/
 obj-$(CONFIG_VP_VDPA)    += virtio_pci/
+obj-$(CONFIG_ALIBABA_ENI_VDPA) += alibaba/
diff --git a/drivers/vdpa/alibaba/Makefile b/drivers/vdpa/alibaba/Makefile
new file mode 100644
index 000000000000..ef4aae69f87a
--- /dev/null
+++ b/drivers/vdpa/alibaba/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_ALIBABA_ENI_VDPA) += eni_vdpa.o
+
diff --git a/drivers/vdpa/alibaba/eni_vdpa.c b/drivers/vdpa/alibaba/eni_vdpa.c
new file mode 100644
index 000000000000..3f788794571a
--- /dev/null
+++ b/drivers/vdpa/alibaba/eni_vdpa.c
@@ -0,0 +1,553 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vDPA bridge driver for Alibaba ENI(Elastic Network Interface)
+ *
+ * Copyright (c) 2021, Alibaba Inc. All rights reserved.
+ * Author: Wu Zongyong <wuzongyong@linux.alibaba.com>
+ *
+ */
+
+#include "linux/bits.h"
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/vdpa.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_pci.h>
+#include <linux/virtio_pci_legacy.h>
+#include <uapi/linux/virtio_net.h>
+
+#define ENI_MSIX_NAME_SIZE 256
+
+#define ENI_ERR(pdev, fmt, ...)	\
+	dev_err(&pdev->dev, "%s"fmt, "eni_vdpa: ", ##__VA_ARGS__)
+#define ENI_DBG(pdev, fmt, ...)	\
+	dev_dbg(&pdev->dev, "%s"fmt, "eni_vdpa: ", ##__VA_ARGS__)
+#define ENI_INFO(pdev, fmt, ...) \
+	dev_info(&pdev->dev, "%s"fmt, "eni_vdpa: ", ##__VA_ARGS__)
+
+struct eni_vring {
+	void __iomem *notify;
+	char msix_name[ENI_MSIX_NAME_SIZE];
+	struct vdpa_callback cb;
+	int irq;
+};
+
+struct eni_vdpa {
+	struct vdpa_device vdpa;
+	struct virtio_pci_legacy_device ldev;
+	struct eni_vring *vring;
+	struct vdpa_callback config_cb;
+	char msix_name[ENI_MSIX_NAME_SIZE];
+	int config_irq;
+	int queues;
+	int vectors;
+};
+
+static struct eni_vdpa *vdpa_to_eni(struct vdpa_device *vdpa)
+{
+	return container_of(vdpa, struct eni_vdpa, vdpa);
+}
+
+static struct virtio_pci_legacy_device *vdpa_to_ldev(struct vdpa_device *vdpa)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+
+	return &eni_vdpa->ldev;
+}
+
+static u64 eni_vdpa_get_features(struct vdpa_device *vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+	u64 features = vp_legacy_get_features(ldev);
+
+	features |= BIT_ULL(VIRTIO_F_ACCESS_PLATFORM);
+	features |= BIT_ULL(VIRTIO_F_ORDER_PLATFORM);
+
+	return features;
+}
+
+static int eni_vdpa_set_features(struct vdpa_device *vdpa, u64 features)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	if (!(features & BIT_ULL(VIRTIO_NET_F_MRG_RXBUF)) && features) {
+		ENI_ERR(ldev->pci_dev,
+			"VIRTIO_NET_F_MRG_RXBUF is not negotiated\n");
+		return -EINVAL;
+	}
+
+	vp_legacy_set_features(ldev, (u32)features);
+
+	return 0;
+}
+
+static u8 eni_vdpa_get_status(struct vdpa_device *vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	return vp_legacy_get_status(ldev);
+}
+
+static int eni_vdpa_get_vq_irq(struct vdpa_device *vdpa, u16 idx)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+	int irq = eni_vdpa->vring[idx].irq;
+
+	if (irq == VIRTIO_MSI_NO_VECTOR)
+		return -EINVAL;
+
+	return irq;
+}
+
+static void eni_vdpa_free_irq(struct eni_vdpa *eni_vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	struct pci_dev *pdev = ldev->pci_dev;
+	int i;
+
+	for (i = 0; i < eni_vdpa->queues; i++) {
+		if (eni_vdpa->vring[i].irq != VIRTIO_MSI_NO_VECTOR) {
+			vp_legacy_queue_vector(ldev, i, VIRTIO_MSI_NO_VECTOR);
+			devm_free_irq(&pdev->dev, eni_vdpa->vring[i].irq,
+				      &eni_vdpa->vring[i]);
+			eni_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
+		}
+	}
+
+	if (eni_vdpa->config_irq != VIRTIO_MSI_NO_VECTOR) {
+		vp_legacy_config_vector(ldev, VIRTIO_MSI_NO_VECTOR);
+		devm_free_irq(&pdev->dev, eni_vdpa->config_irq, eni_vdpa);
+		eni_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
+	}
+
+	if (eni_vdpa->vectors) {
+		pci_free_irq_vectors(pdev);
+		eni_vdpa->vectors = 0;
+	}
+}
+
+static irqreturn_t eni_vdpa_vq_handler(int irq, void *arg)
+{
+	struct eni_vring *vring = arg;
+
+	if (vring->cb.callback)
+		return vring->cb.callback(vring->cb.private);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t eni_vdpa_config_handler(int irq, void *arg)
+{
+	struct eni_vdpa *eni_vdpa = arg;
+
+	if (eni_vdpa->config_cb.callback)
+		return eni_vdpa->config_cb.callback(eni_vdpa->config_cb.private);
+
+	return IRQ_HANDLED;
+}
+
+static int eni_vdpa_request_irq(struct eni_vdpa *eni_vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	struct pci_dev *pdev = ldev->pci_dev;
+	int i, ret, irq;
+	int queues = eni_vdpa->queues;
+	int vectors = queues + 1;
+
+	ret = pci_alloc_irq_vectors(pdev, vectors, vectors, PCI_IRQ_MSIX);
+	if (ret != vectors) {
+		ENI_ERR(pdev,
+			"failed to allocate irq vectors want %d but %d\n",
+			vectors, ret);
+		return ret;
+	}
+
+	eni_vdpa->vectors = vectors;
+
+	for (i = 0; i < queues; i++) {
+		snprintf(eni_vdpa->vring[i].msix_name, ENI_MSIX_NAME_SIZE,
+			 "eni-vdpa[%s]-%d\n", pci_name(pdev), i);
+		irq = pci_irq_vector(pdev, i);
+		ret = devm_request_irq(&pdev->dev, irq,
+				       eni_vdpa_vq_handler,
+				       0, eni_vdpa->vring[i].msix_name,
+				       &eni_vdpa->vring[i]);
+		if (ret) {
+			ENI_ERR(pdev, "failed to request irq for vq %d\n", i);
+			goto err;
+		}
+		vp_legacy_queue_vector(ldev, i, i);
+		eni_vdpa->vring[i].irq = irq;
+	}
+
+	snprintf(eni_vdpa->msix_name, ENI_MSIX_NAME_SIZE, "eni-vdpa[%s]-config\n",
+		 pci_name(pdev));
+	irq = pci_irq_vector(pdev, queues);
+	ret = devm_request_irq(&pdev->dev, irq, eni_vdpa_config_handler, 0,
+			       eni_vdpa->msix_name, eni_vdpa);
+	if (ret) {
+		ENI_ERR(pdev, "failed to request irq for config vq %d\n", i);
+		goto err;
+	}
+	vp_legacy_config_vector(ldev, queues);
+	eni_vdpa->config_irq = irq;
+
+	return 0;
+err:
+	eni_vdpa_free_irq(eni_vdpa);
+	return ret;
+}
+
+static void eni_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	u8 s = eni_vdpa_get_status(vdpa);
+
+	if (status & VIRTIO_CONFIG_S_DRIVER_OK &&
+	    !(s & VIRTIO_CONFIG_S_DRIVER_OK)) {
+		eni_vdpa_request_irq(eni_vdpa);
+	}
+
+	vp_legacy_set_status(ldev, status);
+
+	if (!(status & VIRTIO_CONFIG_S_DRIVER_OK) &&
+	    (s & VIRTIO_CONFIG_S_DRIVER_OK))
+		eni_vdpa_free_irq(eni_vdpa);
+}
+
+static int eni_vdpa_reset(struct vdpa_device *vdpa)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	u8 s = eni_vdpa_get_status(vdpa);
+
+	vp_legacy_set_status(ldev, 0);
+
+	if (s & VIRTIO_CONFIG_S_DRIVER_OK)
+		eni_vdpa_free_irq(eni_vdpa);
+
+	return 0;
+}
+
+static u16 eni_vdpa_get_vq_num_max(struct vdpa_device *vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	return vp_legacy_get_queue_size(ldev, 0);
+}
+
+static u16 eni_vdpa_get_vq_num_min(struct vdpa_device *vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	return vp_legacy_get_queue_size(ldev, 0);
+}
+
+static int eni_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
+				struct vdpa_vq_state *state)
+{
+	return -EOPNOTSUPP;
+}
+
+static int eni_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
+				 const struct vdpa_vq_state *state)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+	const struct vdpa_vq_state_split *split = &state->split;
+
+	/* ENI is build upon virtio-pci specfication which not support
+	 * to set state of virtqueue. But if the state is equal to the
+	 * device initial state by chance, we can let it go.
+	 */
+	if (!vp_legacy_get_queue_enable(ldev, qid)
+	    && split->avail_index == 0)
+		return 0;
+
+	return -EOPNOTSUPP;
+}
+
+
+static void eni_vdpa_set_vq_cb(struct vdpa_device *vdpa, u16 qid,
+			       struct vdpa_callback *cb)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+
+	eni_vdpa->vring[qid].cb = *cb;
+}
+
+static void eni_vdpa_set_vq_ready(struct vdpa_device *vdpa, u16 qid,
+				  bool ready)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	/* ENI is a legacy virtio-pci device. This is not supported
+	 * by specification. But we can disable virtqueue by setting
+	 * address to 0.
+	 */
+	if (!ready)
+		vp_legacy_set_queue_address(ldev, qid, 0);
+}
+
+static bool eni_vdpa_get_vq_ready(struct vdpa_device *vdpa, u16 qid)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	return vp_legacy_get_queue_enable(ldev, qid);
+}
+
+static void eni_vdpa_set_vq_num(struct vdpa_device *vdpa, u16 qid,
+			       u32 num)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+	struct pci_dev *pdev = ldev->pci_dev;
+	u16 n = vp_legacy_get_queue_size(ldev, qid);
+
+	/* ENI is a legacy virtio-pci device which not allow to change
+	 * virtqueue size. Just report a error if someone tries to
+	 * change it.
+	 */
+	if (num != n)
+		ENI_ERR(pdev,
+			"not support to set vq %u fixed num %u to %u\n",
+			qid, n, num);
+}
+
+static int eni_vdpa_set_vq_address(struct vdpa_device *vdpa, u16 qid,
+				   u64 desc_area, u64 driver_area,
+				   u64 device_area)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+	u32 pfn = desc_area >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
+
+	vp_legacy_set_queue_address(ldev, qid, pfn);
+
+	return 0;
+}
+
+static void eni_vdpa_kick_vq(struct vdpa_device *vdpa, u16 qid)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+
+	iowrite16(qid, eni_vdpa->vring[qid].notify);
+}
+
+static u32 eni_vdpa_get_device_id(struct vdpa_device *vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	return ldev->id.device;
+}
+
+static u32 eni_vdpa_get_vendor_id(struct vdpa_device *vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = vdpa_to_ldev(vdpa);
+
+	return ldev->id.vendor;
+}
+
+static u32 eni_vdpa_get_vq_align(struct vdpa_device *vdpa)
+{
+	return VIRTIO_PCI_VRING_ALIGN;
+}
+
+static size_t eni_vdpa_get_config_size(struct vdpa_device *vdpa)
+{
+	return sizeof(struct virtio_net_config);
+}
+
+
+static void eni_vdpa_get_config(struct vdpa_device *vdpa,
+				unsigned int offset,
+				void *buf, unsigned int len)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	void __iomem *ioaddr = ldev->ioaddr +
+		VIRTIO_PCI_CONFIG_OFF(eni_vdpa->vectors) +
+		offset;
+	u8 *p = buf;
+	int i;
+
+	for (i = 0; i < len; i++)
+		*p++ = ioread8(ioaddr + i);
+}
+
+static void eni_vdpa_set_config(struct vdpa_device *vdpa,
+				unsigned int offset, const void *buf,
+				unsigned int len)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	void __iomem *ioaddr = ldev->ioaddr +
+		VIRTIO_PCI_CONFIG_OFF(eni_vdpa->vectors) +
+		offset;
+	const u8 *p = buf;
+	int i;
+
+	for (i = 0; i < len; i++)
+		iowrite8(*p++, ioaddr + i);
+}
+
+static void eni_vdpa_set_config_cb(struct vdpa_device *vdpa,
+				   struct vdpa_callback *cb)
+{
+	struct eni_vdpa *eni_vdpa = vdpa_to_eni(vdpa);
+
+	eni_vdpa->config_cb = *cb;
+}
+
+static const struct vdpa_config_ops eni_vdpa_ops = {
+	.get_features	= eni_vdpa_get_features,
+	.set_features	= eni_vdpa_set_features,
+	.get_status	= eni_vdpa_get_status,
+	.set_status	= eni_vdpa_set_status,
+	.reset		= eni_vdpa_reset,
+	.get_vq_num_max	= eni_vdpa_get_vq_num_max,
+	.get_vq_num_min	= eni_vdpa_get_vq_num_min,
+	.get_vq_state	= eni_vdpa_get_vq_state,
+	.set_vq_state	= eni_vdpa_set_vq_state,
+	.set_vq_cb	= eni_vdpa_set_vq_cb,
+	.set_vq_ready	= eni_vdpa_set_vq_ready,
+	.get_vq_ready	= eni_vdpa_get_vq_ready,
+	.set_vq_num	= eni_vdpa_set_vq_num,
+	.set_vq_address	= eni_vdpa_set_vq_address,
+	.kick_vq	= eni_vdpa_kick_vq,
+	.get_device_id	= eni_vdpa_get_device_id,
+	.get_vendor_id	= eni_vdpa_get_vendor_id,
+	.get_vq_align	= eni_vdpa_get_vq_align,
+	.get_config_size = eni_vdpa_get_config_size,
+	.get_config	= eni_vdpa_get_config,
+	.set_config	= eni_vdpa_set_config,
+	.set_config_cb  = eni_vdpa_set_config_cb,
+	.get_vq_irq	= eni_vdpa_get_vq_irq,
+};
+
+
+static u16 eni_vdpa_get_num_queues(struct eni_vdpa *eni_vdpa)
+{
+	struct virtio_pci_legacy_device *ldev = &eni_vdpa->ldev;
+	u32 features = vp_legacy_get_features(ldev);
+	u16 num = 2;
+
+	if (features & BIT_ULL(VIRTIO_NET_F_MQ)) {
+		__virtio16 max_virtqueue_pairs;
+
+		eni_vdpa_get_config(&eni_vdpa->vdpa,
+			offsetof(struct virtio_net_config, max_virtqueue_pairs),
+			&max_virtqueue_pairs,
+			sizeof(max_virtqueue_pairs));
+		num = 2 * __virtio16_to_cpu(virtio_legacy_is_little_endian(),
+				max_virtqueue_pairs);
+	}
+
+	if (features & BIT_ULL(VIRTIO_NET_F_CTRL_VQ))
+		num += 1;
+
+	return num;
+}
+
+static void eni_vdpa_free_irq_vectors(void *data)
+{
+	pci_free_irq_vectors(data);
+}
+
+static int eni_vdpa_probe(struct pci_dev *pdev, const struct pci_device_id *id)
+{
+	struct device *dev = &pdev->dev;
+	struct eni_vdpa *eni_vdpa;
+	struct virtio_pci_legacy_device *ldev;
+	int ret, i;
+
+	ret = pcim_enable_device(pdev);
+	if (ret)
+		return ret;
+
+	eni_vdpa = vdpa_alloc_device(struct eni_vdpa, vdpa,
+				     dev, &eni_vdpa_ops, NULL, false);
+	if (IS_ERR(eni_vdpa)) {
+		ENI_ERR(pdev, "failed to allocate vDPA structure\n");
+		return PTR_ERR(eni_vdpa);
+	}
+
+	ldev = &eni_vdpa->ldev;
+	ldev->pci_dev = pdev;
+
+	ret = vp_legacy_probe(ldev);
+	if (ret) {
+		ENI_ERR(pdev, "failed to probe legacy PCI device\n");
+		goto err;
+	}
+
+	pci_set_master(pdev);
+	pci_set_drvdata(pdev, eni_vdpa);
+
+	eni_vdpa->vdpa.dma_dev = &pdev->dev;
+	eni_vdpa->queues = eni_vdpa_get_num_queues(eni_vdpa);
+
+	ret = devm_add_action_or_reset(dev, eni_vdpa_free_irq_vectors, pdev);
+	if (ret) {
+		ENI_ERR(pdev,
+			"failed for adding devres for freeing irq vectors\n");
+		goto err;
+	}
+
+	eni_vdpa->vring = devm_kcalloc(&pdev->dev, eni_vdpa->queues,
+				      sizeof(*eni_vdpa->vring),
+				      GFP_KERNEL);
+	if (!eni_vdpa->vring) {
+		ret = -ENOMEM;
+		ENI_ERR(pdev, "failed to allocate virtqueues\n");
+		goto err;
+	}
+
+	for (i = 0; i < eni_vdpa->queues; i++) {
+		eni_vdpa->vring[i].irq = VIRTIO_MSI_NO_VECTOR;
+		eni_vdpa->vring[i].notify = ldev->ioaddr + VIRTIO_PCI_QUEUE_NOTIFY;
+	}
+	eni_vdpa->config_irq = VIRTIO_MSI_NO_VECTOR;
+
+	ret = vdpa_register_device(&eni_vdpa->vdpa, eni_vdpa->queues);
+	if (ret) {
+		ENI_ERR(pdev, "failed to register to vdpa bus\n");
+		goto err;
+	}
+
+	return 0;
+
+err:
+	put_device(&eni_vdpa->vdpa.dev);
+	return ret;
+}
+
+static void eni_vdpa_remove(struct pci_dev *pdev)
+{
+	struct eni_vdpa *eni_vdpa = pci_get_drvdata(pdev);
+
+	vdpa_unregister_device(&eni_vdpa->vdpa);
+	vp_legacy_remove(&eni_vdpa->ldev);
+}
+
+static struct pci_device_id eni_pci_ids[] = {
+	{ PCI_DEVICE_SUB(PCI_VENDOR_ID_REDHAT_QUMRANET,
+			 VIRTIO_TRANS_ID_NET,
+			 PCI_SUBVENDOR_ID_REDHAT_QUMRANET,
+			 VIRTIO_ID_NET) },
+	{ 0 },
+};
+
+static struct pci_driver eni_vdpa_driver = {
+	.name		= "alibaba-eni-vdpa",
+	.id_table	= eni_pci_ids,
+	.probe		= eni_vdpa_probe,
+	.remove		= eni_vdpa_remove,
+};
+
+module_pci_driver(eni_vdpa_driver);
+
+MODULE_AUTHOR("Wu Zongyong <wuzongyong@linux.alibaba.com>");
+MODULE_DESCRIPTION("Alibaba ENI vDPA driver");
+MODULE_LICENSE("GPL v2");