[PATCH v2 2/2] tools/virtio: implement virtqueue in test

zhenwei pi
2023-05-17T02:57:09Z

virtqueue related functions has been abstract since commit
("virtio: abstract virtqueue related methods"), add compatible for
abstract API.

Signed-off-by: zhenwei pi <pizhenwei@bytedance.com>
---
tools/virtio/linux/virtio.h | 355 ++++++++++++++++++++++++++++++++----
1 file changed, 324 insertions(+), 31 deletions(-)

diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
index 5d3440f474dd..3531dba53584 100644
--- a/tools/virtio/linux/virtio.h
+++ b/tools/virtio/linux/virtio.h
@@ -4,6 +4,7 @@
#include <linux/scatterlist.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
+#include <linux/virtio_ring.h>

struct device {
void *parent;
@@ -27,46 +28,338 @@ struct virtqueue {
unsigned int num_max;
void *priv;
bool reset;
+ bool abstract;
+
+ /* abstract operations */
+ int (*add_sgs)(struct virtqueue *vq, struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs, unsigned int in_sgs,
+ void *data, void *ctx, gfp_t gfp);
+ bool (*kick_prepare)(struct virtqueue *vq);
+ bool (*notify)(struct virtqueue *vq);
+ unsigned int (*enable_cb_prepare)(struct virtqueue *vq);
+ bool (*enable_cb_delayed)(struct virtqueue *vq);
+ void (*disable_cb)(struct virtqueue *vq);
+ bool (*poll)(struct virtqueue *vq, unsigned int idx);
+ void *(*get_buf_ctx)(struct virtqueue *vq, unsigned int *len, void **ctx);
+ void *(*detach_unused_buf)(struct virtqueue *vq);
+ unsigned int (*get_vring_size)(const struct virtqueue *vq);
+ int (*resize)(struct virtqueue *vq, u32 num,
+ void (*recycle)(struct virtqueue *vq, void *buf));
+ void (*__break)(struct virtqueue *vq);
+ void (*__unbreak)(struct virtqueue *vq);
+ bool (*is_broken)(const struct virtqueue *vq);
};

-/* Interfaces exported by virtio_ring. */
-int virtqueue_add_sgs(struct virtqueue *vq,
- struct scatterlist *sgs[],
- unsigned int out_sgs,
- unsigned int in_sgs,
- void *data,
- gfp_t gfp);
+/**
+ * virtqueue_add_sgs - expose buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sgs: array of terminated scatterlists.
+ * @out_sgs: the number of scatterlists readable by other side
+ * @in_sgs: the number of scatterlists which are writable (after readable ones)
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * 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 (ie. ENOSPC, ENOMEM, EIO).
+ */
+static inline int virtqueue_add_sgs(struct virtqueue *vq,
+ struct scatterlist *sgs[],
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data, gfp_t gfp)
+{
+ unsigned int i, total_sg = 0;

-int virtqueue_add_outbuf(struct virtqueue *vq,
- struct scatterlist sg[], unsigned int num,
- void *data,
- gfp_t gfp);
+ /* Count them first. */
+ for (i = 0; i < out_sgs + in_sgs; i++) {
+ struct scatterlist *sg;

-int virtqueue_add_inbuf(struct virtqueue *vq,
- struct scatterlist sg[], unsigned int num,
- void *data,
- gfp_t gfp);
+ for (sg = sgs[i]; sg; sg = sg_next(sg))
+ total_sg++;
+ }

-bool virtqueue_kick(struct virtqueue *vq);
+ if (likely(!vq->abstract))
+ return vring_virtqueue_add_sgs(vq, sgs, total_sg, out_sgs, in_sgs, data, NULL, gfp);

-void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
+ return vq->add_sgs(vq, sgs, total_sg, out_sgs, in_sgs, data, NULL, gfp);
+}

-void virtqueue_disable_cb(struct virtqueue *vq);
+/**
+ * virtqueue_add_outbuf - expose output buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg readable by other side
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * 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 (ie. ENOSPC, ENOMEM, EIO).
+ */
+static inline int virtqueue_add_outbuf(struct virtqueue *vq,
+ struct scatterlist *sg,
+ unsigned int num,
+ void *data,
+ gfp_t gfp)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_add_sgs(vq, &sg, num, 1, 0, data, NULL, gfp);

-bool virtqueue_enable_cb(struct virtqueue *vq);
-bool virtqueue_enable_cb_delayed(struct virtqueue *vq);
+ return vq->add_sgs(vq, &sg, num, 1, 0, data, NULL, gfp);
+}

-void *virtqueue_detach_unused_buf(struct virtqueue *vq);
-struct virtqueue *vring_new_virtqueue(unsigned int index,
+/**
+ * virtqueue_add_inbuf - expose input buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg writable by other side
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * 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 (ie. ENOSPC, ENOMEM, EIO).
+ */
+static inline int virtqueue_add_inbuf(struct virtqueue *vq,
+ struct scatterlist *sg,
unsigned int num,
- unsigned int vring_align,
- struct virtio_device *vdev,
- bool weak_barriers,
- bool ctx,
- void *pages,
- bool (*notify)(struct virtqueue *vq),
- void (*callback)(struct virtqueue *vq),
- const char *name);
-void vring_del_virtqueue(struct virtqueue *vq);
+ void *data,
+ gfp_t gfp)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_add_sgs(vq, &sg, num, 0, 1, data, NULL, gfp);
+
+ return vq->add_sgs(vq, &sg, num, 0, 1, data, NULL, gfp);
+}
+
+/**
+ * virtqueue_add_inbuf_ctx - expose input buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg writable by other side
+ * @data: the token identifying the buffer.
+ * @ctx: extra context for the token
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * 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 (ie. ENOSPC, ENOMEM, EIO).
+ */
+static inline int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
+ struct scatterlist *sg,
+ unsigned int num,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_add_sgs(vq, &sg, num, 0, 1, data, ctx, gfp);
+
+ return vq->add_sgs(vq, &sg, num, 0, 1, data, ctx, gfp);
+}
+
+/**
+ * virtqueue_kick_prepare - first half of split virtqueue_kick call.
+ * @vq: the struct virtqueue
+ *
+ * Instead of virtqueue_kick(), you can do:
+ * if (virtqueue_kick_prepare(vq))
+ * virtqueue_notify(vq);
+ *
+ * This is sometimes useful because the virtqueue_kick_prepare() needs
+ * to be serialized, but the actual virtqueue_notify() call does not.
+ */
+static inline bool virtqueue_kick_prepare(struct virtqueue *vq)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_kick_prepare(vq);
+
+ return vq->kick_prepare(vq);
+}
+
+/**
+ * virtqueue_notify - second half of split virtqueue_kick call.
+ * @vq: the struct virtqueue
+ *
+ * This does not need to be serialized.
+ *
+ * Returns false if host notify failed or queue is broken, otherwise true.
+ */
+static inline bool virtqueue_notify(struct virtqueue *vq)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_notify(vq);
+
+ return vq->notify(vq);
+}
+
+/**
+ * virtqueue_kick - update after add_buf
+ * @vq: the struct virtqueue
+ *
+ * After one or more virtqueue_add_* calls, invoke this to kick
+ * the other side.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns false if kick failed, otherwise true.
+ */
+static inline bool virtqueue_kick(struct virtqueue *vq)
+{
+ if (virtqueue_kick_prepare(vq))
+ return virtqueue_notify(vq);
+
+ return true;
+}
+
+/**
+ * virtqueue_enable_cb_prepare - restart callbacks after disable_cb
+ * @vq: the struct virtqueue we're talking about.
+ *
+ * This re-enables callbacks; it returns current queue state
+ * in an opaque unsigned value. This value should be later tested by
+ * virtqueue_poll, to detect a possible race between the driver checking for
+ * more work, and enabling callbacks.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+static inline unsigned int virtqueue_enable_cb_prepare(struct virtqueue *vq)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_enable_cb_prepare(vq);
+
+ return vq->enable_cb_prepare(vq);
+}
+
+/**
+ * virtqueue_poll - query pending used buffers
+ * @vq: the struct virtqueue we're talking about.
+ * @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare).
+ *
+ * Returns "true" if there are pending used buffers in the queue.
+ *
+ * This does not need to be serialized.
+ */
+static inline bool virtqueue_poll(struct virtqueue *vq, unsigned int idx)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_poll(vq, idx);
+
+ return vq->poll(vq, idx);
+}
+
+/**
+ * virtqueue_enable_cb - restart callbacks after disable_cb.
+ * @vq: the struct virtqueue we're talking about.
+ *
+ * This re-enables callbacks; it returns "false" if there are pending
+ * buffers in the queue, to detect a possible race between the driver
+ * checking for more work, and enabling callbacks.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+static inline bool virtqueue_enable_cb(struct virtqueue *vq)
+{
+ unsigned int opaque = virtqueue_enable_cb_prepare(vq);
+
+ return !virtqueue_poll(vq, opaque);
+}
+
+/**
+ * virtqueue_enable_cb_delayed - restart callbacks after disable_cb.
+ * @vq: the struct virtqueue we're talking about.
+ *
+ * This re-enables callbacks but hints to the other side to delay
+ * interrupts until most of the available buffers have been processed;
+ * it returns "false" if there are many pending buffers in the queue,
+ * to detect a possible race between the driver checking for more work,
+ * and enabling callbacks.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+static inline bool virtqueue_enable_cb_delayed(struct virtqueue *vq)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_enable_cb_delayed(vq);
+
+ return vq->enable_cb_delayed(vq);
+}
+
+/**
+ * virtqueue_disable_cb - disable callbacks
+ * @vq: the struct virtqueue we're talking about.
+ *
+ * Note that this is not necessarily synchronous, hence unreliable and only
+ * useful as an optimization.
+ *
+ * Unlike other operations, this need not be serialized.
+ */
+static inline void virtqueue_disable_cb(struct virtqueue *vq)
+{
+ if (likely(!vq->abstract)) {
+ vring_virtqueue_disable_cb(vq);
+ return;
+ }
+
+ vq->disable_cb(vq);
+}
+
+/**
+ * virtqueue_get_buf_ctx - get the next used buffer
+ * @vq: the struct virtqueue we're talking about.
+ * @len: the length written into the buffer
+ * @ctx: extra context for the token
+ *
+ * If the device wrote data into the buffer, @len will be set to the
+ * amount written. This means you don't need to clear the buffer
+ * beforehand to ensure there's no data leakage in the case of short
+ * writes.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns NULL if there are no used buffers, or the "data" token
+ * handed to virtqueue_add_*().
+ */
+static inline void *virtqueue_get_buf_ctx(struct virtqueue *vq,
+ unsigned int *len,
+ void **ctx)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_get_buf_ctx(vq, len, ctx);
+
+ return vq->get_buf_ctx(vq, len, ctx);
+}
+
+static inline void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len)
+{
+ if (likely(!vq->abstract))
+ return vring_virtqueue_get_buf_ctx(vq, len, NULL);
+
+ return vq->get_buf_ctx(vq, len, NULL);
+}
+
+/**
+ * virtqueue_detach_unused_buf - detach first unused buffer
+ * @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 for device
+ * shutdown or the reset queue.
+ */
+static inline void *virtqueue_detach_unused_buf(struct virtqueue *vq)
+{
+ return vq->detach_unused_buf(vq);
+}

#endif
--
2.20.1