tools/virtio: virtio_test tool

This is the userspace part of the tool: it includes a bunch of stubs for
linux APIs, somewhat simular to linuxsched. This makes it possible to
recompile the ring code in userspace.

A small test example is implemented combining this with vhost_test
module.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

3 files changed, 227 insertions, 0 deletions

diff --git a/tools/virtio/linux/device.h b/tools/virtio/linux/device.h
new file mode 100644
index 000000000000..4ad7e1df0db5
--- /dev/null
+++ b/tools/virtio/linux/device.h
@@ -0,0 +1,2 @@
+#ifndef LINUX_DEVICE_H
+#endif
diff --git a/tools/virtio/linux/slab.h b/tools/virtio/linux/slab.h
new file mode 100644
index 000000000000..81baeac8ae40
--- /dev/null
+++ b/tools/virtio/linux/slab.h
@@ -0,0 +1,2 @@
+#ifndef LINUX_SLAB_H
+#endif
diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
new file mode 100644
index 000000000000..669bcdd45805
--- /dev/null
+++ b/tools/virtio/linux/virtio.h
@@ -0,0 +1,223 @@
+#ifndef LINUX_VIRTIO_H
+#define LINUX_VIRTIO_H
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+#include <assert.h>
+
+#include <linux/types.h>
+#include <errno.h>
+
+typedef unsigned long long dma_addr_t;
+
+struct scatterlist {
+        unsigned long   page_link;
+        unsigned int    offset;
+        unsigned int    length;
+        dma_addr_t      dma_address;
+};
+
+struct page {
+        unsigned long long dummy;
+};
+
+#define BUG_ON(__BUG_ON_cond) assert(!(__BUG_ON_cond))
+
+/* Physical == Virtual */
+#define virt_to_phys(p) ((unsigned long)p)
+#define phys_to_virt(a) ((void *)(unsigned long)(a))
+/* Page address: Virtual / 4K */
+#define virt_to_page(p) ((struct page*)((virt_to_phys(p) / 4096) * \
+                                        sizeof(struct page)))
+#define offset_in_page(p) (((unsigned long)p) % 4096)
+#define sg_phys(sg) ((sg->page_link & ~0x3) / sizeof(struct page) * 4096 + \
+                     sg->offset)
+static inline void sg_mark_end(struct scatterlist *sg)
+{
+        /*
+         * Set termination bit, clear potential chain bit
+         */
+        sg->page_link |= 0x02;
+        sg->page_link &= ~0x01;
+}
+static inline void sg_init_table(struct scatterlist *sgl, unsigned int nents)
+{
+        memset(sgl, 0, sizeof(*sgl) * nents);
+        sg_mark_end(&sgl[nents - 1]);
+}
+static inline void sg_assign_page(struct scatterlist *sg, struct page *page)
+{
+        unsigned long page_link = sg->page_link & 0x3;
+
+        /*
+         * In order for the low bit stealing approach to work, pages
+         * must be aligned at a 32-bit boundary as a minimum.
+         */
+        BUG_ON((unsigned long) page & 0x03);
+        sg->page_link = page_link | (unsigned long) page;
+}
+
+static inline void sg_set_page(struct scatterlist *sg, struct page *page,
+                               unsigned int len, unsigned int offset)
+{
+        sg_assign_page(sg, page);
+        sg->offset = offset;
+        sg->length = len;
+}
+
+static inline void sg_set_buf(struct scatterlist *sg, const void *buf,
+                              unsigned int buflen)
+{
+        sg_set_page(sg, virt_to_page(buf), buflen, offset_in_page(buf));
+}
+
+static inline void sg_init_one(struct scatterlist *sg, const void *buf, unsigned int buflen)
+{
+        sg_init_table(sg, 1);
+        sg_set_buf(sg, buf, buflen);
+}
+
+typedef __u16 u16;
+
+typedef enum {
+        GFP_KERNEL,
+        GFP_ATOMIC,
+} gfp_t;
+typedef enum {
+        IRQ_NONE,
+        IRQ_HANDLED
+} irqreturn_t;
+
+static inline void *kmalloc(size_t s, gfp_t gfp)
+{
+        return malloc(s);
+}
+
+static inline void kfree(void *p)
+{
+        free(p);
+}
+
+#define container_of(ptr, type, member) ({                      \
+        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
+        (type *)( (char *)__mptr - offsetof(type,member) );})
+
+#define uninitialized_var(x) x = x
+
+# ifndef likely
+#  define likely(x)     (__builtin_expect(!!(x), 1))
+# endif
+# ifndef unlikely
+#  define unlikely(x)   (__builtin_expect(!!(x), 0))
+# endif
+
+#define pr_err(format, ...) fprintf (stderr, format, ## __VA_ARGS__)
+#ifdef DEBUG
+#define pr_debug(format, ...) fprintf (stderr, format, ## __VA_ARGS__)
+#else
+#define pr_debug(format, ...) do {} while (0)
+#endif
+#define dev_err(dev, format, ...) fprintf (stderr, format, ## __VA_ARGS__)
+#define dev_warn(dev, format, ...) fprintf (stderr, format, ## __VA_ARGS__)
+
+/* TODO: empty stubs for now. Broken but enough for virtio_ring.c */
+#define list_add_tail(a, b) do {} while (0)
+#define list_del(a) do {} while (0)
+
+#define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
+#define BITS_PER_BYTE           8
+#define BITS_PER_LONG (sizeof(long) * BITS_PER_BYTE)
+#define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
+/* TODO: Not atomic as it should be:
+ * we don't use this for anything important. */
+static inline void clear_bit(int nr, volatile unsigned long *addr)
+{
+        unsigned long mask = BIT_MASK(nr);
+        unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
+
+        *p &= ~mask;
+}
+
+static inline int test_bit(int nr, const volatile unsigned long *addr)
+{
+        return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
+}
+
+/* The only feature we care to support */
+#define virtio_has_feature(dev, feature) \
+        test_bit((feature), (dev)->features)
+/* end of stubs */
+
+struct virtio_device {
+        void *dev;
+        unsigned long features[1];
+};
+
+struct virtqueue {
+        /* TODO: commented as list macros are empty stubs for now.
+         * Broken but enough for virtio_ring.c
+         * struct list_head list; */
+        void (*callback)(struct virtqueue *vq);
+        const char *name;
+        struct virtio_device *vdev;
+        void *priv;
+};
+
+#define EXPORT_SYMBOL_GPL(__EXPORT_SYMBOL_GPL_name) \
+        void __EXPORT_SYMBOL_GPL##__EXPORT_SYMBOL_GPL_name() { \
+}
+#define MODULE_LICENSE(__MODULE_LICENSE_value) \
+        const char *__MODULE_LICENSE_name = __MODULE_LICENSE_value
+
+#define CONFIG_SMP
+
+#if defined(__i386__) || defined(__x86_64__)
+#define barrier() asm volatile("" ::: "memory")
+#define mb() __sync_synchronize()
+
+#define smp_mb()        mb()
+# define smp_rmb()      barrier()
+# define smp_wmb()      barrier()
+#else
+#error Please fill in barrier macros
+#endif
+
+/* Interfaces exported by virtio_ring. */
+int virtqueue_add_buf_gfp(struct virtqueue *vq,
+                          struct scatterlist sg[],
+                          unsigned int out_num,
+                          unsigned int in_num,
+                          void *data,
+                          gfp_t gfp);
+
+static inline int virtqueue_add_buf(struct virtqueue *vq,
+                                    struct scatterlist sg[],
+                                    unsigned int out_num,
+                                    unsigned int in_num,
+                                    void *data)
+{
+        return virtqueue_add_buf_gfp(vq, sg, out_num, in_num, data, GFP_ATOMIC);
+}
+
+void virtqueue_kick(struct virtqueue *vq);
+
+void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
+
+void virtqueue_disable_cb(struct virtqueue *vq);
+
+bool virtqueue_enable_cb(struct virtqueue *vq);
+
+void *virtqueue_detach_unused_buf(struct virtqueue *vq);
+struct virtqueue *vring_new_virtqueue(unsigned int num,
+                                      unsigned int vring_align,
+                                      struct virtio_device *vdev,
+                                      void *pages,
+                                      void (*notify)(struct virtqueue *vq),
+                                      void (*callback)(struct virtqueue *vq),
+                                      const char *name);
+void vring_del_virtqueue(struct virtqueue *vq);
+
+#endif