thr3ads.net - Virtualization - [PATCH v8 07/16] virtio_ring: split: extract the logic of alloc state and extra [Mar 2022]

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Xuan Zhuo

2022-Mar-14 09:34 UTC

[PATCH v8 00/16] virtio pci support VIRTIO_F_RING_RESET (refactor vring)

The virtio spec already supports the virtio queue reset function. This patch set
is to add this function to the kernel. The relevant virtio spec information is
here:

    https://github.com/oasis-tcs/virtio-spec/issues/124

Also regarding MMIO support for queue reset, I plan to support it after this
patch is passed.

This patch set implements the refactoring of vring. Finally, the
virtuque_resize() interface is provided based on the reset function of the
transport layer.

Test environment:
    Host: 4.19.91
    Qemu: QEMU emulator version 6.2.50 (with vq reset support)
    Test Cmd:  ethtool -G eth1 rx $1 tx $2; ethtool -g eth1

    The default is split mode, modify Qemu virtio-net to add PACKED feature to
test
    packed mode.

Please review. Thanks.

v8:
  1. Provide a virtqueue_reset() interface directly
  2. Split the two patch sets, this is the first part
  3. Add independent allocation helper for allocating state, extra

v7:
  1. fix #6 subject typo
  2. fix #6 ring_size_in_bytes is uninitialized
  3. check by: make W=12

v6:
  1. virtio_pci: use synchronize_irq(irq) to sync the irq callbacks
  2. Introduce virtqueue_reset_vring() to implement the reset of vring during
     the reset process. May use the old vring if num of the vq not change.
  3. find_vqs() support sizes to special the max size of each vq

v5:
  1. add virtio-net support set_ringparam

v4:
  1. just the code of virtio, without virtio-net
  2. Performing reset on a queue is divided into these steps:
    1. reset_vq: reset one vq
    2. recycle the buffer from vq by virtqueue_detach_unused_buf()
    3. release the ring of the vq by vring_release_virtqueue()
    4. enable_reset_vq: re-enable the reset queue
  3. Simplify the parameters of enable_reset_vq()
  4. add container structures for virtio_pci_common_cfg

v3:
  1. keep vq, irq unreleased

Xuan Zhuo (16):
  virtio: add helper virtqueue_get_vring_max_size()
  virtio: struct virtio_config_ops add callbacks for queue_reset
  virtio_ring: update the document of the virtqueue_detach_unused_buf
    for queue reset
  virtio_ring: remove the arg vq of vring_alloc_desc_extra()
  virtio_ring: extract the logic of freeing vring
  virtio_ring: split: extract the logic of alloc queue
  virtio_ring: split: extract the logic of alloc state and extra
  virtio_ring: split: extract the logic of attach vring
  virtio_ring: split: extract the logic of vq init
  virtio_ring: split: implement virtqueue_resize_split()
  virtio_ring: packed: extract the logic of alloc queue
  virtio_ring: packed: extract the logic of alloc state and extra
  virtio_ring: packed: extract the logic of attach vring
  virtio_ring: packed: extract the logic of vq init
  virtio_ring: packed: implement virtqueue_resize_packed()
  virtio_ring: introduce virtqueue_resize()

 drivers/virtio/virtio_mmio.c       |   2 +
 drivers/virtio/virtio_pci_legacy.c |   2 +
 drivers/virtio/virtio_pci_modern.c |   2 +
 drivers/virtio/virtio_ring.c       | 604 ++++++++++++++++++++++-------
 include/linux/virtio.h             |   5 +
 include/linux/virtio_config.h      |  12 +
 6 files changed, 494 insertions(+), 133 deletions(-)

--
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 01/16] virtio: add helper virtqueue_get_vring_max_size()

Record the maximum queue num supported by the device.

virtio-net can display the maximum (supported by hardware) ring size in
ethtool -g eth0.

When the subsequent patch implements vring reset, it can judge whether
the ring size passed by the driver is legal based on this.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
Acked-by: Jason Wang <jasowang at redhat.com>
---
 drivers/virtio/virtio_mmio.c       |  2 ++
 drivers/virtio/virtio_pci_legacy.c |  2 ++
 drivers/virtio/virtio_pci_modern.c |  2 ++
 drivers/virtio/virtio_ring.c       | 14 ++++++++++++++
 include/linux/virtio.h             |  2 ++
 5 files changed, 22 insertions(+)

diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 56128b9c46eb..a41abc8051b9 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -390,6 +390,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device
*vdev, unsigned index,
 		goto error_new_virtqueue;
 	}
 
+	vq->num_max = num;
+
 	/* Activate the queue */
 	writel(virtqueue_get_vring_size(vq), vm_dev->base + VIRTIO_MMIO_QUEUE_NUM);
 	if (vm_dev->version == 1) {
diff --git a/drivers/virtio/virtio_pci_legacy.c
b/drivers/virtio/virtio_pci_legacy.c
index 34141b9abe27..b68934fe6b5d 100644
--- a/drivers/virtio/virtio_pci_legacy.c
+++ b/drivers/virtio/virtio_pci_legacy.c
@@ -135,6 +135,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device
*vp_dev,
 	if (!vq)
 		return ERR_PTR(-ENOMEM);
 
+	vq->num_max = num;
+
 	q_pfn = virtqueue_get_desc_addr(vq) >> VIRTIO_PCI_QUEUE_ADDR_SHIFT;
 	if (q_pfn >> 32) {
 		dev_err(&vp_dev->pci_dev->dev,
diff --git a/drivers/virtio/virtio_pci_modern.c
b/drivers/virtio/virtio_pci_modern.c
index 5455bc041fb6..86d301f272b8 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -218,6 +218,8 @@ static struct virtqueue *setup_vq(struct virtio_pci_device
*vp_dev,
 	if (!vq)
 		return ERR_PTR(-ENOMEM);
 
+	vq->num_max = num;
+
 	/* activate the queue */
 	vp_modern_set_queue_size(mdev, index, virtqueue_get_vring_size(vq));
 	vp_modern_queue_address(mdev, index, virtqueue_get_desc_addr(vq),
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 962f1477b1fa..b87130c8f312 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2371,6 +2371,20 @@ void vring_transport_features(struct virtio_device *vdev)
 }
 EXPORT_SYMBOL_GPL(vring_transport_features);
 
+/**
+ * virtqueue_get_vring_max_size - return the max size of the virtqueue's
vring
+ * @_vq: the struct virtqueue containing the vring of interest.
+ *
+ * Returns the max size of the vring.
+ *
+ * Unlike other operations, this need not be serialized.
+ */
+unsigned int virtqueue_get_vring_max_size(struct virtqueue *_vq)
+{
+	return _vq->num_max;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_vring_max_size);
+
 /**
  * virtqueue_get_vring_size - return the size of the virtqueue's vring
  * @_vq: the struct virtqueue containing the vring of interest.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 72292a62cd90..d59adc4be068 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -31,6 +31,7 @@ struct virtqueue {
 	struct virtio_device *vdev;
 	unsigned int index;
 	unsigned int num_free;
+	unsigned int num_max;
 	void *priv;
 };
 
@@ -80,6 +81,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
 
 void *virtqueue_detach_unused_buf(struct virtqueue *vq);
 
+unsigned int virtqueue_get_vring_max_size(struct virtqueue *vq);
 unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
 
 bool virtqueue_is_broken(struct virtqueue *vq);
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 02/16] virtio: struct virtio_config_ops add callbacks for queue_reset

Performing reset on a queue is divided into four steps:

 1. transport: notify the device to reset the queue
 2. vring:     recycle the buffer submitted
 3. vring:     reset/resize the vring (may re-alloc)
 4. transport: mmap vring to device, and enable the queue

In order to support queue reset, add two callbacks(reset_vq,
enable_reset_vq) in struct virtio_config_ops to implement steps 1 and 4.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 include/linux/virtio_config.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 4d107ad31149..d4adcd0e1c57 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -74,6 +74,16 @@ struct virtio_shm_region {
  * @set_vq_affinity: set the affinity for a virtqueue (optional).
  * @get_vq_affinity: get the affinity for a virtqueue (optional).
  * @get_shm_region: get a shared memory region based on the index.
+ * @reset_vq: reset a queue individually (optional).
+ *	vq: the virtqueue
+ *	Returns 0 on success or error status
+ *	reset_vq will guarantee that the callbacks are disabled and synchronized.
+ *	Except for the callback, the caller should guarantee that the vring is
+ *	not accessed by any functions of virtqueue.
+ * @enable_reset_vq: enable a reset queue
+ *	vq: the virtqueue
+ *	Returns 0 on success or error status
+ *	If reset_vq is set, then enable_reset_vq must also be set.
  */
 typedef void vq_callback_t(struct virtqueue *);
 struct virtio_config_ops {
@@ -100,6 +110,8 @@ struct virtio_config_ops {
 			int index);
 	bool (*get_shm_region)(struct virtio_device *vdev,
 			       struct virtio_shm_region *region, u8 id);
+	int (*reset_vq)(struct virtqueue *vq);
+	int (*enable_reset_vq)(struct virtqueue *vq);
 };
 
 /* If driver didn't advertise the feature, it will never appear. */
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 03/16] virtio_ring: update the document of the virtqueue_detach_unused_buf for queue reset

Added documentation for virtqueue_detach_unused_buf, allowing it to be
called on queue reset.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index b87130c8f312..f1807f6b06a5 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2127,8 +2127,8 @@ EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
  * @_vq: the struct virtqueue we're talking about.
  *
  * Returns NULL or the "data" token handed to virtqueue_add_*().
- * This is not valid on an active queue; it is useful only for device
- * shutdown.
+ * This is not valid on an active queue; it is useful for device
+ * shutdown or the reset queue.
  */
 void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
 {
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 04/16] virtio_ring: remove the arg vq of vring_alloc_desc_extra()

The parameter vq of vring_alloc_desc_extra() is useless. This patch
removes this parameter.

Subsequent patches will call this function to avoid passing useless
arguments.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index f1807f6b06a5..cb6010750a94 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1636,8 +1636,7 @@ static void *virtqueue_detach_unused_buf_packed(struct
virtqueue *_vq)
 	return NULL;
 }
 
-static struct vring_desc_extra *vring_alloc_desc_extra(struct vring_virtqueue
*vq,
-						       unsigned int num)
+static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num)
 {
 	struct vring_desc_extra *desc_extra;
 	unsigned int i;
@@ -1755,7 +1754,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	/* Put everything in free lists. */
 	vq->free_head = 0;
 
-	vq->packed.desc_extra = vring_alloc_desc_extra(vq, num);
+	vq->packed.desc_extra = vring_alloc_desc_extra(num);
 	if (!vq->packed.desc_extra)
 		goto err_desc_extra;
 
@@ -2233,7 +2232,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 	if (!vq->split.desc_state)
 		goto err_state;
 
-	vq->split.desc_extra = vring_alloc_desc_extra(vq, vring.num);
+	vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
 	if (!vq->split.desc_extra)
 		goto err_extra;
 
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 05/16] virtio_ring: extract the logic of freeing vring

Introduce __vring_free() to free the vring of vq.

Subsequent patches will use __vring_free() alone.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cb6010750a94..763532a2ffe4 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2301,14 +2301,10 @@ struct virtqueue *vring_new_virtqueue(unsigned int
index,
 }
 EXPORT_SYMBOL_GPL(vring_new_virtqueue);
 
-void vring_del_virtqueue(struct virtqueue *_vq)
+static void __vring_free(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
-	spin_lock(&vq->vq.vdev->vqs_list_lock);
-	list_del(&_vq->list);
-	spin_unlock(&vq->vq.vdev->vqs_list_lock);
-
 	if (vq->we_own_ring) {
 		if (vq->packed_ring) {
 			vring_free_queue(vq->vq.vdev,
@@ -2339,6 +2335,18 @@ void vring_del_virtqueue(struct virtqueue *_vq)
 		kfree(vq->split.desc_state);
 		kfree(vq->split.desc_extra);
 	}
+}
+
+void vring_del_virtqueue(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	spin_lock(&vq->vq.vdev->vqs_list_lock);
+	list_del(&_vq->list);
+	spin_unlock(&vq->vq.vdev->vqs_list_lock);
+
+	__vring_free(_vq);
+
 	kfree(vq);
 }
 EXPORT_SYMBOL_GPL(vring_del_virtqueue);
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 06/16] virtio_ring: split: extract the logic of alloc queue

Separate the logic of split to create vring queue.

This feature is required for subsequent virtuqueue reset vring.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 53 ++++++++++++++++++++++++------------
 1 file changed, 36 insertions(+), 17 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 763532a2ffe4..d7667f74c42b 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -915,23 +915,15 @@ static void *virtqueue_detach_unused_buf_split(struct
virtqueue *_vq)
 	return NULL;
 }
 
-static struct virtqueue *vring_create_virtqueue_split(
-	unsigned int index,
-	unsigned int num,
-	unsigned int vring_align,
-	struct virtio_device *vdev,
-	bool weak_barriers,
-	bool may_reduce_num,
-	bool context,
-	bool (*notify)(struct virtqueue *),
-	void (*callback)(struct virtqueue *),
-	const char *name)
+static void *vring_alloc_queue_split(struct virtio_device *vdev,
+				     dma_addr_t *dma_addr,
+				     u32 *n,
+				     unsigned int vring_align,
+				     bool weak_barriers,
+				     bool may_reduce_num)
 {
-	struct virtqueue *vq;
 	void *queue = NULL;
-	dma_addr_t dma_addr;
-	size_t queue_size_in_bytes;
-	struct vring vring;
+	u32 num = *n;
 
 	/* We assume num is a power of 2. */
 	if (num & (num - 1)) {
@@ -942,7 +934,7 @@ static struct virtqueue *vring_create_virtqueue_split(
 	/* TODO: allocate each queue chunk individually */
 	for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
 		queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
-					  &dma_addr,
+					  dma_addr,
 					  GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
 		if (queue)
 			break;
@@ -956,11 +948,38 @@ static struct virtqueue *vring_create_virtqueue_split(
 	if (!queue) {
 		/* Try to get a single page. You are my only hope! */
 		queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
-					  &dma_addr, GFP_KERNEL|__GFP_ZERO);
+					  dma_addr, GFP_KERNEL|__GFP_ZERO);
 	}
 	if (!queue)
 		return NULL;
 
+	*n = num;
+	return queue;
+}
+
+static struct virtqueue *vring_create_virtqueue_split(
+	unsigned int index,
+	unsigned int num,
+	unsigned int vring_align,
+	struct virtio_device *vdev,
+	bool weak_barriers,
+	bool may_reduce_num,
+	bool context,
+	bool (*notify)(struct virtqueue *),
+	void (*callback)(struct virtqueue *),
+	const char *name)
+{
+	size_t queue_size_in_bytes;
+	struct virtqueue *vq;
+	dma_addr_t dma_addr;
+	struct vring vring;
+	void *queue;
+
+	queue = vring_alloc_queue_split(vdev, &dma_addr, &num, vring_align,
+					weak_barriers, may_reduce_num);
+	if (!queue)
+		return NULL;
+
 	queue_size_in_bytes = vring_size(num, vring_align);
 	vring_init(&vring, num, queue, vring_align);
 
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 07/16] virtio_ring: split: extract the logic of alloc state and extra

Separate the logic of creating desc_state, desc_extra, and subsequent
patches will call it independently.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 52 +++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 15 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index d7667f74c42b..9b850188c38e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2186,6 +2186,33 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
 }
 EXPORT_SYMBOL_GPL(vring_interrupt);
 
+static int __vring_alloc_state_extra_split(u32 num,
+					   struct vring_desc_state_split **desc_state,
+					   struct vring_desc_extra **desc_extra)
+{
+	struct vring_desc_state_split *state;
+	struct vring_desc_extra *extra;
+
+	state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
+	if (!state)
+		goto err_state;
+
+	extra = vring_alloc_desc_extra(num);
+	if (!extra)
+		goto err_extra;
+
+	memset(state, 0, num * sizeof(struct vring_desc_state_split));
+
+	*desc_state = state;
+	*desc_extra = extra;
+	return 0;
+
+err_extra:
+	kfree(state);
+err_state:
+	return -ENOMEM;
+}
+
 /* Only available for split ring */
 struct virtqueue *__vring_new_virtqueue(unsigned int index,
 					struct vring vring,
@@ -2196,7 +2223,10 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 					void (*callback)(struct virtqueue *),
 					const char *name)
 {
+	struct vring_desc_state_split *state;
+	struct vring_desc_extra *extra;
 	struct vring_virtqueue *vq;
+	int err;
 
 	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
 		return NULL;
@@ -2246,30 +2276,22 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 					vq->split.avail_flags_shadow);
 	}
 
-	vq->split.desc_state = kmalloc_array(vring.num,
-			sizeof(struct vring_desc_state_split), GFP_KERNEL);
-	if (!vq->split.desc_state)
-		goto err_state;
+	err = __vring_alloc_state_extra_split(vring.num, &state, &extra);
+	if (err) {
+		kfree(vq);
+		return NULL;
+	}
 
-	vq->split.desc_extra = vring_alloc_desc_extra(vring.num);
-	if (!vq->split.desc_extra)
-		goto err_extra;
+	vq->split.desc_state = state;
+	vq->split.desc_extra = extra;
 
 	/* Put everything in free lists. */
 	vq->free_head = 0;
-	memset(vq->split.desc_state, 0, vring.num *
-			sizeof(struct vring_desc_state_split));
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);
 	spin_unlock(&vdev->vqs_list_lock);
 	return &vq->vq;
-
-err_extra:
-	kfree(vq->split.desc_state);
-err_state:
-	kfree(vq);
-	return NULL;
 }
 EXPORT_SYMBOL_GPL(__vring_new_virtqueue);
 
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 08/16] virtio_ring: split: extract the logic of attach vring

Separate the logic of attach vring, subsequent patches will call it
separately.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 9b850188c38e..6ed10c46d6d6 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2213,6 +2213,21 @@ static int __vring_alloc_state_extra_split(u32 num,
 	return -ENOMEM;
 }
 
+static void __vring_virtqueue_attach_split(struct vring_virtqueue *vq,
+					   struct vring vring,
+					   struct vring_desc_state_split *desc_state,
+					   struct vring_desc_extra *desc_extra)
+{
+	vq->vq.num_free = vring.num;
+
+	vq->split.vring = vring;
+	vq->split.queue_dma_addr = 0;
+	vq->split.queue_size_in_bytes = 0;
+
+	vq->split.desc_state = desc_state;
+	vq->split.desc_extra = desc_extra;
+}
+
 /* Only available for split ring */
 struct virtqueue *__vring_new_virtqueue(unsigned int index,
 					struct vring vring,
@@ -2239,7 +2254,6 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 	vq->vq.callback = callback;
 	vq->vq.vdev = vdev;
 	vq->vq.name = name;
-	vq->vq.num_free = vring.num;
 	vq->vq.index = index;
 	vq->we_own_ring = false;
 	vq->notify = notify;
@@ -2261,10 +2275,6 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	vq->split.queue_dma_addr = 0;
-	vq->split.queue_size_in_bytes = 0;
-
-	vq->split.vring = vring;
 	vq->split.avail_flags_shadow = 0;
 	vq->split.avail_idx_shadow = 0;
 
@@ -2282,8 +2292,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 		return NULL;
 	}
 
-	vq->split.desc_state = state;
-	vq->split.desc_extra = extra;
+	__vring_virtqueue_attach_split(vq, vring, state, extra);
 
 	/* Put everything in free lists. */
 	vq->free_head = 0;
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 09/16] virtio_ring: split: extract the logic of vq init

Separate the logic of initializing vq, and subsequent patches will call
it separately.

The feature of this part is that it does not depend on the information
passed by the upper layer and can be called repeatedly.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 65 ++++++++++++++++++++----------------
 1 file changed, 36 insertions(+), 29 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6ed10c46d6d6..81bbfd65411e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2228,6 +2228,41 @@ static void __vring_virtqueue_attach_split(struct
vring_virtqueue *vq,
 	vq->split.desc_extra = desc_extra;
 }
 
+static void __vring_virtqueue_init_split(struct vring_virtqueue *vq,
+					 struct virtio_device *vdev)
+{
+	vq->packed_ring = false;
+	vq->we_own_ring = false;
+	vq->broken = false;
+	vq->last_used_idx = 0;
+	vq->event_triggered = false;
+	vq->num_added = 0;
+	vq->use_dma_api = vring_use_dma_api(vdev);
+#ifdef DEBUG
+	vq->in_use = false;
+	vq->last_add_time_valid = false;
+#endif
+
+	vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+
+	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
+		vq->weak_barriers = false;
+
+	vq->split.avail_flags_shadow = 0;
+	vq->split.avail_idx_shadow = 0;
+
+	/* No callback?  Tell other side not to bother us. */
+	if (!vq->vq.callback) {
+		vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+		if (!vq->event)
+			vq->split.vring.avail->flags = cpu_to_virtio16(vdev,
+					vq->split.avail_flags_shadow);
+	}
+
+	/* Put everything in free lists. */
+	vq->free_head = 0;
+}
+
 /* Only available for split ring */
 struct virtqueue *__vring_new_virtqueue(unsigned int index,
 					struct vring vring,
@@ -2250,41 +2285,15 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 	if (!vq)
 		return NULL;
 
-	vq->packed_ring = false;
 	vq->vq.callback = callback;
 	vq->vq.vdev = vdev;
 	vq->vq.name = name;
 	vq->vq.index = index;
-	vq->we_own_ring = false;
 	vq->notify = notify;
 	vq->weak_barriers = weak_barriers;
-	vq->broken = false;
-	vq->last_used_idx = 0;
-	vq->event_triggered = false;
-	vq->num_added = 0;
-	vq->use_dma_api = vring_use_dma_api(vdev);
-#ifdef DEBUG
-	vq->in_use = false;
-	vq->last_add_time_valid = false;
-#endif
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)
&&
 		!context;
-	vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
-
-	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
-		vq->weak_barriers = false;
-
-	vq->split.avail_flags_shadow = 0;
-	vq->split.avail_idx_shadow = 0;
-
-	/* No callback?  Tell other side not to bother us. */
-	if (!callback) {
-		vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
-		if (!vq->event)
-			vq->split.vring.avail->flags = cpu_to_virtio16(vdev,
-					vq->split.avail_flags_shadow);
-	}
 
 	err = __vring_alloc_state_extra_split(vring.num, &state, &extra);
 	if (err) {
@@ -2293,9 +2302,7 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
 	}
 
 	__vring_virtqueue_attach_split(vq, vring, state, extra);
-
-	/* Put everything in free lists. */
-	vq->free_head = 0;
+	__vring_virtqueue_init_split(vq, vdev);
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 10/16] virtio_ring: split: implement virtqueue_resize_split()

virtio ring split supports resize.

Only after the new vring is successfully allocated based on the new num,
we will release the old vring. In any case, an error is returned,
indicating that the vring still points to the old vring. In the case of
an error, we will re-initialize the state of the vring to ensure that
the vring can be used.

In addition, vring_align, may_reduce_num are necessary for reallocating
vring, so they are retained for creating vq.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 62 ++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 81bbfd65411e..a15869514146 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -139,6 +139,12 @@ struct vring_virtqueue {
 			/* DMA address and size information */
 			dma_addr_t queue_dma_addr;
 			size_t queue_size_in_bytes;
+
+			/* The parameters for creating vrings are reserved for
+			 * creating new vrings when enabling reset queue.
+			 */
+			u32 vring_align;
+			bool may_reduce_num;
 		} split;
 
 		/* Available for packed ring */
@@ -198,6 +204,16 @@ struct vring_virtqueue {
 #endif
 };
 
+static void __vring_free(struct virtqueue *_vq);
+static void __vring_virtqueue_init_split(struct vring_virtqueue *vq,
+					 struct virtio_device *vdev);
+static void __vring_virtqueue_attach_split(struct vring_virtqueue *vq,
+					   struct vring vring,
+					   struct vring_desc_state_split *desc_state,
+					   struct vring_desc_extra *desc_extra);
+static int __vring_alloc_state_extra_split(u32 num,
+					   struct vring_desc_state_split **desc_state,
+					   struct vring_desc_extra **desc_extra);
 
 /*
  * Helpers.
@@ -991,6 +1007,8 @@ static struct virtqueue *vring_create_virtqueue_split(
 		return NULL;
 	}
 
+	to_vvq(vq)->split.vring_align = vring_align;
+	to_vvq(vq)->split.may_reduce_num = may_reduce_num;
 	to_vvq(vq)->split.queue_dma_addr = dma_addr;
 	to_vvq(vq)->split.queue_size_in_bytes = queue_size_in_bytes;
 	to_vvq(vq)->we_own_ring = true;
@@ -998,6 +1016,50 @@ static struct virtqueue *vring_create_virtqueue_split(
 	return vq;
 }
 
+static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	struct virtio_device *vdev = _vq->vdev;
+	struct vring_desc_state_split *state;
+	struct vring_desc_extra *extra;
+	size_t queue_size_in_bytes;
+	dma_addr_t dma_addr;
+	struct vring vring;
+	int err = -ENOMEM;
+	void *queue;
+
+	BUG_ON(!vq->we_own_ring);
+
+	queue = vring_alloc_queue_split(vdev, &dma_addr, &num,
+					vq->split.vring_align,
+					vq->weak_barriers,
+					vq->split.may_reduce_num);
+	if (!queue)
+		goto init;
+
+	queue_size_in_bytes = vring_size(num, vq->split.vring_align);
+
+	err = __vring_alloc_state_extra_split(num, &state, &extra);
+	if (err) {
+		vring_free_queue(vdev, queue_size_in_bytes, queue, dma_addr);
+		goto init;
+	}
+
+	__vring_free(&vq->vq);
+
+	vring_init(&vring, num, queue, vq->split.vring_align);
+	__vring_virtqueue_attach_split(vq, vring, state, extra);
+	vq->split.queue_dma_addr = dma_addr;
+	vq->split.queue_size_in_bytes = queue_size_in_bytes;
+
+	err = 0;
+
+init:
+	__vring_virtqueue_init_split(vq, vdev);
+	vq->we_own_ring = true;
+	return err;
+}
+
 
 /*
  * Packed ring specific functions - *_packed().
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 11/16] virtio_ring: packed: extract the logic of alloc queue

Separate the logic of packed to create vring queue.

For the convenience of passing parameters, add a structure
vring_packed.

This feature is required for subsequent virtuqueue reset vring.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 121 ++++++++++++++++++++++++++---------
 1 file changed, 92 insertions(+), 29 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index a15869514146..96ff2dabda14 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -85,6 +85,18 @@ struct vring_desc_extra {
 	u16 next;			/* The next desc state in a list. */
 };
 
+struct vring_packed {
+	u32 num;
+	struct vring_packed_desc *ring;
+	struct vring_packed_desc_event *driver;
+	struct vring_packed_desc_event *device;
+	dma_addr_t ring_dma_addr;
+	dma_addr_t driver_event_dma_addr;
+	dma_addr_t device_event_dma_addr;
+	size_t ring_size_in_bytes;
+	size_t event_size_in_bytes;
+};
+
 struct vring_virtqueue {
 	struct virtqueue vq;
 
@@ -1735,45 +1747,101 @@ static struct vring_desc_extra
*vring_alloc_desc_extra(unsigned int num)
 	return desc_extra;
 }
 
-static struct virtqueue *vring_create_virtqueue_packed(
-	unsigned int index,
-	unsigned int num,
-	unsigned int vring_align,
-	struct virtio_device *vdev,
-	bool weak_barriers,
-	bool may_reduce_num,
-	bool context,
-	bool (*notify)(struct virtqueue *),
-	void (*callback)(struct virtqueue *),
-	const char *name)
+static void vring_free_vring_packed(struct vring_packed *vring,
+				    struct virtio_device *vdev)
+{
+	dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr;
+	struct vring_packed_desc_event *driver, *device;
+	size_t ring_size_in_bytes, event_size_in_bytes;
+	struct vring_packed_desc *ring;
+
+	ring                  = vring->ring;
+	driver                = vring->driver;
+	device                = vring->device;
+	ring_size_in_bytes    = vring->ring_size_in_bytes;
+	event_size_in_bytes   = vring->event_size_in_bytes;
+	ring_dma_addr         = vring->ring_dma_addr;
+	driver_event_dma_addr = vring->driver_event_dma_addr;
+	device_event_dma_addr = vring->device_event_dma_addr;
+
+	if (device)
+		vring_free_queue(vdev, event_size_in_bytes, device, device_event_dma_addr);
+
+	if (driver)
+		vring_free_queue(vdev, event_size_in_bytes, driver, driver_event_dma_addr);
+
+	if (ring)
+		vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr);
+}
+
+static int vring_alloc_queue_packed(struct vring_packed *vring,
+				    struct virtio_device *vdev,
+				    u32 num)
 {
-	struct vring_virtqueue *vq;
 	struct vring_packed_desc *ring;
 	struct vring_packed_desc_event *driver, *device;
 	dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr;
 	size_t ring_size_in_bytes, event_size_in_bytes;
 
+	memset(vring, 0, sizeof(*vring));
+
 	ring_size_in_bytes = num * sizeof(struct vring_packed_desc);
 
 	ring = vring_alloc_queue(vdev, ring_size_in_bytes,
 				 &ring_dma_addr,
 				 GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
 	if (!ring)
-		goto err_ring;
+		goto err;
+
+	vring->num = num;
+	vring->ring = ring;
+	vring->ring_size_in_bytes = ring_size_in_bytes;
+	vring->ring_dma_addr = ring_dma_addr;
 
 	event_size_in_bytes = sizeof(struct vring_packed_desc_event);
+	vring->event_size_in_bytes = event_size_in_bytes;
 
 	driver = vring_alloc_queue(vdev, event_size_in_bytes,
 				   &driver_event_dma_addr,
 				   GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
 	if (!driver)
-		goto err_driver;
+		goto err;
+
+	vring->driver = driver;
+	vring->driver_event_dma_addr = driver_event_dma_addr;
 
 	device = vring_alloc_queue(vdev, event_size_in_bytes,
 				   &device_event_dma_addr,
 				   GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
 	if (!device)
-		goto err_device;
+		goto err;
+
+	vring->device = device;
+	vring->device_event_dma_addr = device_event_dma_addr;
+	return 0;
+
+err:
+	vring_free_vring_packed(vring, vdev);
+	return -ENOMEM;
+}
+
+static struct virtqueue *vring_create_virtqueue_packed(
+	unsigned int index,
+	unsigned int num,
+	unsigned int vring_align,
+	struct virtio_device *vdev,
+	bool weak_barriers,
+	bool may_reduce_num,
+	bool context,
+	bool (*notify)(struct virtqueue *),
+	void (*callback)(struct virtqueue *),
+	const char *name)
+{
+	struct vring_virtqueue *vq;
+	struct vring_packed vring;
+
+	if (vring_alloc_queue_packed(&vring, vdev, num))
+		goto err_vq;
 
 	vq = kmalloc(sizeof(*vq), GFP_KERNEL);
 	if (!vq)
@@ -1805,17 +1873,17 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	vq->packed.ring_dma_addr = ring_dma_addr;
-	vq->packed.driver_event_dma_addr = driver_event_dma_addr;
-	vq->packed.device_event_dma_addr = device_event_dma_addr;
+	vq->packed.ring_dma_addr = vring.ring_dma_addr;
+	vq->packed.driver_event_dma_addr = vring.driver_event_dma_addr;
+	vq->packed.device_event_dma_addr = vring.device_event_dma_addr;
 
-	vq->packed.ring_size_in_bytes = ring_size_in_bytes;
-	vq->packed.event_size_in_bytes = event_size_in_bytes;
+	vq->packed.ring_size_in_bytes = vring.ring_size_in_bytes;
+	vq->packed.event_size_in_bytes = vring.event_size_in_bytes;
 
 	vq->packed.vring.num = num;
-	vq->packed.vring.desc = ring;
-	vq->packed.vring.driver = driver;
-	vq->packed.vring.device = device;
+	vq->packed.vring.desc = vring.ring;
+	vq->packed.vring.driver = vring.driver;
+	vq->packed.vring.device = vring.device;
 
 	vq->packed.next_avail_idx = 0;
 	vq->packed.avail_wrap_counter = 1;
@@ -1856,12 +1924,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 err_desc_state:
 	kfree(vq);
 err_vq:
-	vring_free_queue(vdev, event_size_in_bytes, device, device_event_dma_addr);
-err_device:
-	vring_free_queue(vdev, event_size_in_bytes, driver, driver_event_dma_addr);
-err_driver:
-	vring_free_queue(vdev, ring_size_in_bytes, ring, ring_dma_addr);
-err_ring:
+	vring_free_vring_packed(&vring, vdev);
 	return NULL;
 }
 
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 12/16] virtio_ring: packed: extract the logic of alloc state and extra

Separate the logic for alloc desc_state and desc_extra, which will
be called separately by subsequent patches.

Use struct vring_packed to pass desc_state, desc_extra.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 50 ++++++++++++++++++++++++++----------
 1 file changed, 36 insertions(+), 14 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 96ff2dabda14..980bd77d8243 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -95,6 +95,9 @@ struct vring_packed {
 	dma_addr_t device_event_dma_addr;
 	size_t ring_size_in_bytes;
 	size_t event_size_in_bytes;
+
+	struct vring_desc_state_packed *desc_state;
+	struct vring_desc_extra *desc_extra;
 };
 
 struct vring_virtqueue {
@@ -1825,6 +1828,32 @@ static int vring_alloc_queue_packed(struct vring_packed
*vring,
 	return -ENOMEM;
 }
 
+static int vring_alloc_state_extra_packed(u32 num, struct vring_packed *vring)
+{
+	struct vring_desc_state_packed *state;
+	struct vring_desc_extra *extra;
+
+	state = kmalloc_array(num, sizeof(struct vring_desc_state_packed),
GFP_KERNEL);
+	if (!state)
+		goto err_desc_state;
+
+	memset(state, 0, num * sizeof(struct vring_desc_state_packed));
+
+	extra = vring_alloc_desc_extra(num);
+	if (!extra)
+		goto err_desc_extra;
+
+	vring->desc_state = state;
+	vring->desc_extra = extra;
+
+	return 0;
+
+err_desc_extra:
+	kfree(state);
+err_desc_state:
+	return -ENOMEM;
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
@@ -1839,6 +1868,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 {
 	struct vring_virtqueue *vq;
 	struct vring_packed vring;
+	int err;
 
 	if (vring_alloc_queue_packed(&vring, vdev, num))
 		goto err_vq;
@@ -1891,22 +1921,16 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->packed.event_flags_shadow = 0;
 	vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
 
-	vq->packed.desc_state = kmalloc_array(num,
-			sizeof(struct vring_desc_state_packed),
-			GFP_KERNEL);
-	if (!vq->packed.desc_state)
-		goto err_desc_state;
+	err = vring_alloc_state_extra_packed(num, &vring);
+	if (err)
+		goto err_state_extra;
 
-	memset(vq->packed.desc_state, 0,
-		num * sizeof(struct vring_desc_state_packed));
+	vq->packed.desc_state = vring.desc_state;
+	vq->packed.desc_extra = vring.desc_extra;
 
 	/* Put everything in free lists. */
 	vq->free_head = 0;
 
-	vq->packed.desc_extra = vring_alloc_desc_extra(num);
-	if (!vq->packed.desc_extra)
-		goto err_desc_extra;
-
 	/* No callback?  Tell other side not to bother us. */
 	if (!callback) {
 		vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
@@ -1919,9 +1943,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	spin_unlock(&vdev->vqs_list_lock);
 	return &vq->vq;
 
-err_desc_extra:
-	kfree(vq->packed.desc_state);
-err_desc_state:
+err_state_extra:
 	kfree(vq);
 err_vq:
 	vring_free_vring_packed(&vring, vdev);
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 13/16] virtio_ring: packed: extract the logic of attach vring

Separate the logic of attach vring, the subsequent patch will call it
separately.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 41 +++++++++++++++++++++++-------------
 1 file changed, 26 insertions(+), 15 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 980bd77d8243..e8d4de25e90b 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1854,6 +1854,31 @@ static int vring_alloc_state_extra_packed(u32 num, struct
vring_packed *vring)
 	return -ENOMEM;
 }
 
+static void vring_virtqueue_attach_packed(struct vring_virtqueue *vq,
+					  struct vring_packed *vring)
+{
+	u32 num;
+
+	num = vring->num;
+
+	vq->vq.num_free = num;
+
+	vq->packed.ring_dma_addr = vring->ring_dma_addr;
+	vq->packed.driver_event_dma_addr = vring->driver_event_dma_addr;
+	vq->packed.device_event_dma_addr = vring->device_event_dma_addr;
+
+	vq->packed.ring_size_in_bytes = vring->ring_size_in_bytes;
+	vq->packed.event_size_in_bytes = vring->event_size_in_bytes;
+
+	vq->packed.vring.num = num;
+	vq->packed.vring.desc = vring->ring;
+	vq->packed.vring.driver = vring->driver;
+	vq->packed.vring.device = vring->device;
+
+	vq->packed.desc_state = vring->desc_state;
+	vq->packed.desc_extra = vring->desc_extra;
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
@@ -1880,7 +1905,6 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->vq.callback = callback;
 	vq->vq.vdev = vdev;
 	vq->vq.name = name;
-	vq->vq.num_free = num;
 	vq->vq.index = index;
 	vq->we_own_ring = true;
 	vq->notify = notify;
@@ -1903,18 +1927,6 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	vq->packed.ring_dma_addr = vring.ring_dma_addr;
-	vq->packed.driver_event_dma_addr = vring.driver_event_dma_addr;
-	vq->packed.device_event_dma_addr = vring.device_event_dma_addr;
-
-	vq->packed.ring_size_in_bytes = vring.ring_size_in_bytes;
-	vq->packed.event_size_in_bytes = vring.event_size_in_bytes;
-
-	vq->packed.vring.num = num;
-	vq->packed.vring.desc = vring.ring;
-	vq->packed.vring.driver = vring.driver;
-	vq->packed.vring.device = vring.device;
-
 	vq->packed.next_avail_idx = 0;
 	vq->packed.avail_wrap_counter = 1;
 	vq->packed.used_wrap_counter = 1;
@@ -1925,8 +1937,7 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	if (err)
 		goto err_state_extra;
 
-	vq->packed.desc_state = vring.desc_state;
-	vq->packed.desc_extra = vring.desc_extra;
+	vring_virtqueue_attach_packed(vq, &vring);
 
 	/* Put everything in free lists. */
 	vq->free_head = 0;
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 14/16] virtio_ring: packed: extract the logic of vq init

Separate the logic of initializing vq, and subsequent patches will call
it separately.

The characteristic of this part of the logic is that it does not depend
on the information passed by the upper layer, and can be called
repeatedly.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 69 ++++++++++++++++++++----------------
 1 file changed, 38 insertions(+), 31 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index e8d4de25e90b..73abc9e472ce 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1879,6 +1879,43 @@ static void vring_virtqueue_attach_packed(struct
vring_virtqueue *vq,
 	vq->packed.desc_extra = vring->desc_extra;
 }
 
+static void vring_virtqueue_init_packed(struct vring_virtqueue *vq,
+					struct virtio_device *vdev)
+{
+	vq->we_own_ring = true;
+	vq->broken = false;
+	vq->last_used_idx = 0;
+	vq->event_triggered = false;
+	vq->num_added = 0;
+	vq->packed_ring = true;
+	vq->use_dma_api = vring_use_dma_api(vdev);
+#ifdef DEBUG
+	vq->in_use = false;
+	vq->last_add_time_valid = false;
+#endif
+
+	vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+
+	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
+		vq->weak_barriers = false;
+
+	vq->packed.next_avail_idx = 0;
+	vq->packed.avail_wrap_counter = 1;
+	vq->packed.used_wrap_counter = 1;
+	vq->packed.event_flags_shadow = 0;
+	vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
+
+	/* Put everything in free lists. */
+	vq->free_head = 0;
+
+	/* No callback?  Tell other side not to bother us. */
+	if (!vq->vq.callback) {
+		vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
+		vq->packed.vring.driver->flags +		
cpu_to_le16(vq->packed.event_flags_shadow);
+	}
+}
+
 static struct virtqueue *vring_create_virtqueue_packed(
 	unsigned int index,
 	unsigned int num,
@@ -1906,48 +1943,18 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	vq->vq.vdev = vdev;
 	vq->vq.name = name;
 	vq->vq.index = index;
-	vq->we_own_ring = true;
 	vq->notify = notify;
 	vq->weak_barriers = weak_barriers;
-	vq->broken = false;
-	vq->last_used_idx = 0;
-	vq->event_triggered = false;
-	vq->num_added = 0;
-	vq->packed_ring = true;
-	vq->use_dma_api = vring_use_dma_api(vdev);
-#ifdef DEBUG
-	vq->in_use = false;
-	vq->last_add_time_valid = false;
-#endif
 
 	vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC)
&&
 		!context;
-	vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
-
-	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
-		vq->weak_barriers = false;
-
-	vq->packed.next_avail_idx = 0;
-	vq->packed.avail_wrap_counter = 1;
-	vq->packed.used_wrap_counter = 1;
-	vq->packed.event_flags_shadow = 0;
-	vq->packed.avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
 
 	err = vring_alloc_state_extra_packed(num, &vring);
 	if (err)
 		goto err_state_extra;
 
 	vring_virtqueue_attach_packed(vq, &vring);
-
-	/* Put everything in free lists. */
-	vq->free_head = 0;
-
-	/* No callback?  Tell other side not to bother us. */
-	if (!callback) {
-		vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
-		vq->packed.vring.driver->flags -		
cpu_to_le16(vq->packed.event_flags_shadow);
-	}
+	vring_virtqueue_init_packed(vq, vdev);
 
 	spin_lock(&vdev->vqs_list_lock);
 	list_add_tail(&vq->vq.list, &vdev->vqs);
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 15/16] virtio_ring: packed: implement virtqueue_resize_packed()

virtio ring packed supports resize.

Only after the new vring is successfully allocated based on the new num,
we will release the old vring. In any case, an error is returned,
indicating that the vring still points to the old vring. In the case of
an error, we will re-initialize the state of the vring to ensure that
the vring can be used.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 73abc9e472ce..fb0abf9a2f57 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1968,6 +1968,34 @@ static struct virtqueue *vring_create_virtqueue_packed(
 	return NULL;
 }
 
+static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+	struct virtio_device *vdev = _vq->vdev;
+	struct vring_packed vring;
+	int err;
+
+	err = vring_alloc_queue_packed(&vring, vdev, num);
+	if (err)
+		goto err_queue;
+
+	err = vring_alloc_state_extra_packed(num, &vring);
+	if (err)
+		goto err_state_extra;
+
+	__vring_free(&vq->vq);
+
+	vring_virtqueue_attach_packed(vq, &vring);
+	vring_virtqueue_init_packed(vq, vdev);
+	return 0;
+
+err_state_extra:
+	vring_free_vring_packed(&vring, vdev);
+err_queue:
+	vring_virtqueue_init_packed(vq, vdev);
+	return -ENOMEM;
+}
+
 
 /*
  * Generic functions and exported symbols.
-- 
2.31.0

Xuan Zhuo

2022-Mar-14 09:34 UTC

head link

[PATCH v8 16/16] virtio_ring: introduce virtqueue_resize()

Introduce virtqueue_resize() to implement the resize of vring.
Based on these, the driver can dynamically adjust the size of the vring.
For example: ethtool -G.

virtqueue_resize() implements resize based on the vq reset function. In
case of failure to allocate a new vring, it will give up resize and use
the original vring.

During this process, if the re-enable reset vq fails, the vq can no
longer be used. Although the probability of this situation is not high.

The parameter recycle is used to recycle the buffer that is no longer
used.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 67 ++++++++++++++++++++++++++++++++++++
 include/linux/virtio.h       |  3 ++
 2 files changed, 70 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index fb0abf9a2f57..b1dde086a8a4 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2528,6 +2528,73 @@ struct virtqueue *vring_create_virtqueue(
 }
 EXPORT_SYMBOL_GPL(vring_create_virtqueue);
 
+/**
+ * virtqueue_resize - resize the vring of vq
+ * @vq: the struct virtqueue we're talking about.
+ * @num: new ring num
+ * @recycle: callback for recycle the useless buffer
+ *
+ * When it is really necessary to create a new vring, it will set the current
vq
+ * into the reset state. Then call the passed cb to recycle the buffer that is
+ * no longer used. Only after the new vring is successfully created, the old
+ * vring will be released.
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error.
+ * -ENOMEM: create new vring fail. But vq can still work
+ * -EBUSY:  reset/re-enable vq fail. vq may cannot work
+ * -ENOENT: not support resize
+ * -E2BIG/-EINVAL: param num error
+ */
+int virtqueue_resize(struct virtqueue *vq, u32 num,
+		     void (*recycle)(struct virtqueue *vq, void *buf))
+{
+	struct virtio_device *vdev = vq->vdev;
+	void *buf;
+	int err;
+
+	if (num > vq->num_max)
+		return -E2BIG;
+
+	if (!num)
+		return -EINVAL;
+
+	if (to_vvq(vq)->packed.vring.num == num)
+		return 0;
+
+	if (!vq->vdev->config->reset_vq)
+		return -ENOENT;
+
+	if (!vq->vdev->config->enable_reset_vq)
+		return -ENOENT;
+
+	err = vq->vdev->config->reset_vq(vq);
+	if (err) {
+		if (err != -ENOENT)
+			err = -EBUSY;
+		return err;
+	}
+
+	while ((buf = virtqueue_detach_unused_buf(vq)) != NULL)
+		recycle(vq, buf);
+
+	if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
+		err = virtqueue_resize_packed(vq, num);
+	else
+		err = virtqueue_resize_split(vq, num);
+
+	if (err)
+		err = -ENOMEM;
+
+	if (vq->vdev->config->enable_reset_vq(vq))
+		return -EBUSY;
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(virtqueue_resize);
+
 /* Only available for split ring */
 struct virtqueue *vring_new_virtqueue(unsigned int index,
 				      unsigned int num,
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index d59adc4be068..c86ff02e0ca0 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -91,6 +91,9 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *vq);
 dma_addr_t virtqueue_get_avail_addr(struct virtqueue *vq);
 dma_addr_t virtqueue_get_used_addr(struct virtqueue *vq);
 
+int virtqueue_resize(struct virtqueue *vq, u32 num,
+		     void (*recycle)(struct virtqueue *vq, void *buf));
+
 /**
  * virtio_device - representation of a device using virtio
  * @index: unique position on the virtio bus
-- 
2.31.0

Jason Wang

2022-Mar-22 06:40 UTC

head link

[PATCH v8 00/16] virtio pci support VIRTIO_F_RING_RESET (refactor vring)

? 2022/3/14 ??5:34, Xuan Zhuo ??:> The virtio spec already supports the virtio queue reset function. This
patch set
> is to add this function to the kernel. The relevant virtio spec information
is
> here:
>
>      https://github.com/oasis-tcs/virtio-spec/issues/124
>
> Also regarding MMIO support for queue reset, I plan to support it after
this
> patch is passed.
>
> This patch set implements the refactoring of vring. Finally, the
> virtuque_resize() interface is provided based on the reset function of the
> transport layer.
>
> Test environment:
>      Host: 4.19.91
>      Qemu: QEMU emulator version 6.2.50 (with vq reset support)

It would be better if you can post Qemu code for review as well.

>      Test Cmd:  ethtool -G eth1 rx $1 tx $2; ethtool -g eth1
>
>      The default is split mode, modify Qemu virtio-net to add PACKED
feature to test
>      packed mode.
>
> Please review. Thanks.

Looks good overall, see comments in individual patch.

I think the code is structured in a way that is not friendly to the 
reviewers. For next version, we can bring back the ethtool -G for 
virtio-net.

Thanks

>
> v8:
>    1. Provide a virtqueue_reset() interface directly
>    2. Split the two patch sets, this is the first part
>    3. Add independent allocation helper for allocating state, extra
>
> v7:
>    1. fix #6 subject typo
>    2. fix #6 ring_size_in_bytes is uninitialized
>    3. check by: make W=12
>
> v6:
>    1. virtio_pci: use synchronize_irq(irq) to sync the irq callbacks
>    2. Introduce virtqueue_reset_vring() to implement the reset of vring
during
>       the reset process. May use the old vring if num of the vq not change.
>    3. find_vqs() support sizes to special the max size of each vq
>
> v5:
>    1. add virtio-net support set_ringparam
>
> v4:
>    1. just the code of virtio, without virtio-net
>    2. Performing reset on a queue is divided into these steps:
>      1. reset_vq: reset one vq
>      2. recycle the buffer from vq by virtqueue_detach_unused_buf()
>      3. release the ring of the vq by vring_release_virtqueue()
>      4. enable_reset_vq: re-enable the reset queue
>    3. Simplify the parameters of enable_reset_vq()
>    4. add container structures for virtio_pci_common_cfg
>
> v3:
>    1. keep vq, irq unreleased
>
> Xuan Zhuo (16):
>    virtio: add helper virtqueue_get_vring_max_size()
>    virtio: struct virtio_config_ops add callbacks for queue_reset
>    virtio_ring: update the document of the virtqueue_detach_unused_buf
>      for queue reset
>    virtio_ring: remove the arg vq of vring_alloc_desc_extra()
>    virtio_ring: extract the logic of freeing vring
>    virtio_ring: split: extract the logic of alloc queue
>    virtio_ring: split: extract the logic of alloc state and extra
>    virtio_ring: split: extract the logic of attach vring
>    virtio_ring: split: extract the logic of vq init
>    virtio_ring: split: implement virtqueue_resize_split()
>    virtio_ring: packed: extract the logic of alloc queue
>    virtio_ring: packed: extract the logic of alloc state and extra
>    virtio_ring: packed: extract the logic of attach vring
>    virtio_ring: packed: extract the logic of vq init
>    virtio_ring: packed: implement virtqueue_resize_packed()
>    virtio_ring: introduce virtqueue_resize()
>
>   drivers/virtio/virtio_mmio.c       |   2 +
>   drivers/virtio/virtio_pci_legacy.c |   2 +
>   drivers/virtio/virtio_pci_modern.c |   2 +
>   drivers/virtio/virtio_ring.c       | 604 ++++++++++++++++++++++-------
>   include/linux/virtio.h             |   5 +
>   include/linux/virtio_config.h      |  12 +
>   6 files changed, 494 insertions(+), 133 deletions(-)
>
> --
> 2.31.0
>

Virtualization - Mar 2022 - [PATCH v8 07/16] virtio_ring: split: extract the logic of alloc state and extra

[PATCH v8 00/16] virtio pci support VIRTIO_F_RING_RESET (refactor vring)

[PATCH v8 01/16] virtio: add helper virtqueue_get_vring_max_size()

[PATCH v8 02/16] virtio: struct virtio_config_ops add callbacks for queue_reset

[PATCH v8 03/16] virtio_ring: update the document of the virtqueue_detach_unused_buf for queue reset

[PATCH v8 04/16] virtio_ring: remove the arg vq of vring_alloc_desc_extra()

[PATCH v8 05/16] virtio_ring: extract the logic of freeing vring

[PATCH v8 06/16] virtio_ring: split: extract the logic of alloc queue

[PATCH v8 07/16] virtio_ring: split: extract the logic of alloc state and extra

[PATCH v8 08/16] virtio_ring: split: extract the logic of attach vring

[PATCH v8 09/16] virtio_ring: split: extract the logic of vq init

[PATCH v8 10/16] virtio_ring: split: implement virtqueue_resize_split()

[PATCH v8 11/16] virtio_ring: packed: extract the logic of alloc queue

[PATCH v8 12/16] virtio_ring: packed: extract the logic of alloc state and extra

[PATCH v8 13/16] virtio_ring: packed: extract the logic of attach vring

[PATCH v8 14/16] virtio_ring: packed: extract the logic of vq init

[PATCH v8 15/16] virtio_ring: packed: implement virtqueue_resize_packed()

[PATCH v8 16/16] virtio_ring: introduce virtqueue_resize()

[PATCH v8 00/16] virtio pci support VIRTIO_F_RING_RESET (refactor vring)