libvhost-user: Support tracking inflight I/O in shared memory

This patch adds support for VHOST_USER_GET_INFLIGHT_FD and
VHOST_USER_SET_INFLIGHT_FD message to set/get shared buffer
to/from qemu. Then backend can track inflight I/O in this buffer.

Signed-off-by: Xie Yongji <xieyongji@baidu.com>
Signed-off-by: Zhang Yu <zhangyu31@baidu.com>
Message-Id: <20190228085355.9614-5-xieyongji@baidu.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 70 insertions, 0 deletions

diff --git a/contrib/libvhost-user/libvhost-user.h b/contrib/libvhost-user/libvhost-user.h
index 3de8414898..414ceb0a2f 100644
--- a/contrib/libvhost-user/libvhost-user.h
+++ b/contrib/libvhost-user/libvhost-user.h
@@ -53,6 +53,7 @@ enum VhostUserProtocolFeature {
     VHOST_USER_PROTOCOL_F_CONFIG = 9,
     VHOST_USER_PROTOCOL_F_SLAVE_SEND_FD = 10,
     VHOST_USER_PROTOCOL_F_HOST_NOTIFIER = 11,
+    VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD = 12,
 
     VHOST_USER_PROTOCOL_F_MAX
 };
@@ -91,6 +92,8 @@ typedef enum VhostUserRequest {
     VHOST_USER_POSTCOPY_ADVISE  = 28,
     VHOST_USER_POSTCOPY_LISTEN  = 29,
     VHOST_USER_POSTCOPY_END     = 30,
+    VHOST_USER_GET_INFLIGHT_FD = 31,
+    VHOST_USER_SET_INFLIGHT_FD = 32,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -138,6 +141,13 @@ typedef struct VhostUserVringArea {
     uint64_t offset;
 } VhostUserVringArea;
 
+typedef struct VhostUserInflight {
+    uint64_t mmap_size;
+    uint64_t mmap_offset;
+    uint16_t num_queues;
+    uint16_t queue_size;
+} VhostUserInflight;
+
 #if defined(_WIN32)
 # define VU_PACKED __attribute__((gcc_struct, packed))
 #else
@@ -163,6 +173,7 @@ typedef struct VhostUserMsg {
         VhostUserLog log;
         VhostUserConfig config;
         VhostUserVringArea area;
+        VhostUserInflight inflight;
     } payload;
 
     int fds[VHOST_MEMORY_MAX_NREGIONS];
@@ -234,9 +245,61 @@ typedef struct VuRing {
     uint32_t flags;
 } VuRing;
 
+typedef struct VuDescStateSplit {
+    /* Indicate whether this descriptor is inflight or not.
+     * Only available for head-descriptor. */
+    uint8_t inflight;
+
+    /* Padding */
+    uint8_t padding[5];
+
+    /* Maintain a list for the last batch of used descriptors.
+     * Only available when batching is used for submitting */
+    uint16_t next;
+
+    /* Used to preserve the order of fetching available descriptors.
+     * Only available for head-descriptor. */
+    uint64_t counter;
+} VuDescStateSplit;
+
+typedef struct VuVirtqInflight {
+    /* The feature flags of this region. Now it's initialized to 0. */
+    uint64_t features;
+
+    /* The version of this region. It's 1 currently.
+     * Zero value indicates a vm reset happened. */
+    uint16_t version;
+
+    /* The size of VuDescStateSplit array. It's equal to the virtqueue
+     * size. Slave could get it from queue size field of VhostUserInflight. */
+    uint16_t desc_num;
+
+    /* The head of list that track the last batch of used descriptors. */
+    uint16_t last_batch_head;
+
+    /* Storing the idx value of used ring */
+    uint16_t used_idx;
+
+    /* Used to track the state of each descriptor in descriptor table */
+    VuDescStateSplit desc[0];
+} VuVirtqInflight;
+
+typedef struct VuVirtqInflightDesc {
+    uint16_t index;
+    uint64_t counter;
+} VuVirtqInflightDesc;
+
 typedef struct VuVirtq {
     VuRing vring;
 
+    VuVirtqInflight *inflight;
+
+    VuVirtqInflightDesc *resubmit_list;
+
+    uint16_t resubmit_num;
+
+    uint64_t counter;
+
     /* Next head to pop */
     uint16_t last_avail_idx;
 
@@ -279,11 +342,18 @@ typedef void (*vu_set_watch_cb) (VuDev *dev, int fd, int condition,
                                  vu_watch_cb cb, void *data);
 typedef void (*vu_remove_watch_cb) (VuDev *dev, int fd);
 
+typedef struct VuDevInflightInfo {
+    int fd;
+    void *addr;
+    uint64_t size;
+} VuDevInflightInfo;
+
 struct VuDev {
     int sock;
     uint32_t nregions;
     VuDevRegion regions[VHOST_MEMORY_MAX_NREGIONS];
     VuVirtq vq[VHOST_MAX_NR_VIRTQUEUE];
+    VuDevInflightInfo inflight_info;
     int log_call_fd;
     int slave_fd;
     uint64_t log_size;