Misc fixes for vfu_ctx_try_attach() and vfu_realize_ctx() (#175)

Misc changes for vfu_ctx_try_attach()
* Rename to vfu_attach_ctx()
* Removed call to vfu_realize_ctx(), should be called separately
* Now vfu_attach_ctx() must also be called for blocking ctx.

Misc changes for vfu_realize_ctx()
* Made calling vfu_realize_ctx() mandatory
* vfu_ctx_drive() and vfu_poll_ctx() returns EINVAL if the device is not
realized.
* Renamed vfu_ctx->ready to vfu_ctx->realized

Added unit test for vfu_attach_ctx() and vfu_realize_ctx()

Signed-off-by: Swapnil Ingle <swapnil.ingle@nutanix.com>
Reviewed-by: Thanos Makatos <thanos.makatos@nutanix.com>

2 files changed, 8 insertions, 38 deletions

diff --git a/lib/libvfio-user.c b/lib/libvfio-user.c
index 007169f..5e04794 100644
--- a/lib/libvfio-user.c
+++ b/lib/libvfio-user.c
@@ -1085,30 +1085,13 @@ vfu_realize_ctx(vfu_ctx_t *vfu_ctx)
 {
     vfu_reg_info_t *cfg_reg;
     const vfu_reg_info_t zero_reg = { 0 };
-    int err;
     uint32_t max_ivs = 0, i;
     size_t size;
 
-    if (vfu_ctx->ready) {
+    if (vfu_ctx->realized) {
         return 0;
     }
 
-    /*
-     * With LIBVFIO_USER_FLAG_ATTACH_NB caller is always expected to call
-     * vfu_ctx_try_attach().
-     */
-    if ((vfu_ctx->flags & LIBVFIO_USER_FLAG_ATTACH_NB) == 0) {
-        vfu_ctx->conn_fd = vfu_ctx->trans->attach(vfu_ctx);
-        if (vfu_ctx->conn_fd < 0) {
-            err = vfu_ctx->conn_fd;
-            if (err != EINTR) {
-                vfu_log(vfu_ctx, LOG_ERR, "failed to attach: %s",
-                       strerror(-err));
-            }
-            return ERROR(err);
-        }
-    }
-
     cfg_reg = &vfu_ctx->reg_info[VFU_PCI_DEV_CFG_REGION_IDX];
 
     // Set a default config region if none provided.
@@ -1173,7 +1156,7 @@ vfu_realize_ctx(vfu_ctx_t *vfu_ctx)
         vfu_ctx->pci.config_space->hdr.sts.cl = 0x1;
         vfu_ctx->pci.config_space->hdr.cap = PCI_STD_HEADER_SIZEOF;
     }
-    vfu_ctx->ready = true;
+    vfu_ctx->realized = true;
 
     return 0;
 }
@@ -1183,15 +1166,10 @@ vfu_ctx_drive(vfu_ctx_t *vfu_ctx)
 {
     int err;
 
-    if (vfu_ctx == NULL) {
+    if (vfu_ctx == NULL || !vfu_ctx->realized) {
         return ERROR(EINVAL);
     }
 
-    err = vfu_realize_ctx(vfu_ctx);
-    if (err == -1) {
-        return -1;
-    }
-
     do {
         err = process_request(vfu_ctx);
     } while (err >= 0);
@@ -1208,7 +1186,9 @@ vfu_ctx_poll(vfu_ctx_t *vfu_ctx)
         return -ENOTSUP;
     }
 
-    assert(vfu_ctx->ready);
+    if (!vfu_ctx->realized) {
+        return ERROR(EINVAL);
+    }
     err = process_request(vfu_ctx);
 
     return err >= 0 ? 0 : err;
@@ -1269,21 +1249,11 @@ vfu_destroy_ctx(vfu_ctx_t *vfu_ctx)
 }
 
 int
-vfu_ctx_try_attach(vfu_ctx_t *vfu_ctx)
+vfu_attach_ctx(vfu_ctx_t *vfu_ctx)
 {
-    int err;
 
     assert(vfu_ctx != NULL);
 
-    if ((vfu_ctx->flags & LIBVFIO_USER_FLAG_ATTACH_NB) == 0) {
-        return ERROR(EINVAL);
-    }
-
-    err = vfu_realize_ctx(vfu_ctx);
-    if (err == -1) {
-        return err;
-    }
-
     return vfu_ctx->trans->attach(vfu_ctx);
 }
 
diff --git a/lib/private.h b/lib/private.h
index 1321b8f..e8afd79 100644
--- a/lib/private.h
+++ b/lib/private.h
@@ -129,7 +129,7 @@ struct vfu_ctx {
 
     uint32_t                irq_count[VFU_DEV_NUM_IRQS];
     vfu_irqs_t              *irqs;
-    bool                    ready;
+    bool                    realized;
     vfu_dev_type_t          dev_type;
 };