[PATCH v4 07/14] vfio-user: run vfio-user context

[Jagannathan Raman]

Setup a handler to run vfio-user context. The context is driven by
messages to the file descriptor associated with it - get the fd for
the context and hook up the handler with it

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
Signed-off-by: John G Johnson <john.g.johnson@oracle.com>
Signed-off-by: Jagannathan Raman <jag.raman@oracle.com>
---
 hw/remote/vfio-user-obj.c | 80 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 79 insertions(+), 1 deletion(-)

diff --git a/hw/remote/vfio-user-obj.c b/hw/remote/vfio-user-obj.c
index bcbea59bf1..a01a0ad185 100644
--- a/hw/remote/vfio-user-obj.c
+++ b/hw/remote/vfio-user-obj.c
@@ -42,10 +42,12 @@
 #include "qapi/error.h"
 #include "qapi/qapi-visit-sockets.h"
 #include "qemu/notify.h"
+#include "qemu/thread.h"
 #include "sysemu/sysemu.h"
 #include "libvfio-user.h"
 #include "hw/qdev-core.h"
 #include "hw/pci/pci.h"
+#include "qemu/timer.h"
 
 #define TYPE_VFU_OBJECT "x-vfio-user-server"
 OBJECT_DECLARE_TYPE(VfuObject, VfuObjectClass, VFU_OBJECT)
@@ -73,6 +75,8 @@ struct VfuObject {
     vfu_ctx_t *vfu_ctx;
 
     PCIDevice *pci_dev;
+
+    int vfu_poll_fd;
 };
 
 static void vfu_object_init_ctx(VfuObject *o, Error **errp);
@@ -114,6 +118,62 @@ static void vfu_object_set_device(Object *obj, const char 
*str, Error **errp)
     vfu_object_init_ctx(o, errp);
 }
 
+static void vfu_object_ctx_run(void *opaque)
+{
+    VfuObject *o = opaque;
+    int ret = -1;
+
+    while (ret != 0) {
+        ret = vfu_run_ctx(o->vfu_ctx);
+        if (ret < 0) {
+            if (errno == EINTR) {
+                continue;
+            } else if (errno == ENOTCONN) {
+                qemu_set_fd_handler(o->vfu_poll_fd, NULL, NULL, NULL);
+                o->vfu_poll_fd = -1;
+                object_unparent(OBJECT(o));
+                break;
+            } else {
+                error_setg(&error_abort, "vfu: Failed to run device %s - %s",
+                           o->device, strerror(errno));
+                 break;
+            }
+        }
+    }
+}
+
+static void vfu_object_attach_ctx(void *opaque)
+{
+    VfuObject *o = opaque;
+    GPollFD pfds[1];
+    int ret;
+
+    qemu_set_fd_handler(o->vfu_poll_fd, NULL, NULL, NULL);
+
+    pfds[0].fd = o->vfu_poll_fd;
+    pfds[0].events = G_IO_IN | G_IO_HUP | G_IO_ERR;
+
+retry_attach:
+    ret = vfu_attach_ctx(o->vfu_ctx);
+    if (ret < 0 && (errno == EAGAIN || errno == EWOULDBLOCK)) {
+        qemu_poll_ns(pfds, 1, 500 * (int64_t)SCALE_MS);
+        goto retry_attach;
+    } else if (ret < 0) {
+        error_setg(&error_abort,
+                   "vfu: Failed to attach device %s to context - %s",
+                   o->device, strerror(errno));
+        return;
+    }
+
+    o->vfu_poll_fd = vfu_get_poll_fd(o->vfu_ctx);
+    if (o->vfu_poll_fd < 0) {
+        error_setg(&error_abort, "vfu: Failed to get poll fd %s", o->device);
+        return;
+    }
+
+    qemu_set_fd_handler(o->vfu_poll_fd, vfu_object_ctx_run, NULL, o);
+}
+
 /*
  * TYPE_VFU_OBJECT depends on the availability of the 'socket' and 'device'
  * properties. It also depends on devices instantiated in QEMU. These
@@ -151,7 +211,8 @@ static void vfu_object_init_ctx(VfuObject *o, Error **errp)
         return;
     }
 
-    o->vfu_ctx = vfu_create_ctx(VFU_TRANS_SOCK, o->socket->u.q_unix.path, 0,
+    o->vfu_ctx = vfu_create_ctx(VFU_TRANS_SOCK, o->socket->u.q_unix.path,
+                                LIBVFIO_USER_FLAG_ATTACH_NB,
                                 o, VFU_DEV_TYPE_PCI);
     if (o->vfu_ctx == NULL) {
         error_setg(errp, "vfu: Failed to create context - %s", 
strerror(errno));
@@ -183,6 +244,21 @@ static void vfu_object_init_ctx(VfuObject *o, Error **errp)
         goto fail;
     }
 
+    ret = vfu_realize_ctx(o->vfu_ctx);
+    if (ret < 0) {
+        error_setg(errp, "vfu: Failed to realize device %s- %s",
+                   o->device, strerror(errno));
+        goto fail;
+    }
+
+    o->vfu_poll_fd = vfu_get_poll_fd(o->vfu_ctx);
+    if (o->vfu_poll_fd < 0) {
+        error_setg(errp, "vfu: Failed to get poll fd %s", o->device);
+        goto fail;
+    }
+
+    qemu_set_fd_handler(o->vfu_poll_fd, vfu_object_attach_ctx, NULL, o);
+
     return;
 
 fail:
@@ -208,6 +284,8 @@ static void vfu_object_init(Object *obj)
                    TYPE_VFU_OBJECT, TYPE_REMOTE_MACHINE);
         return;
     }
+
+    o->vfu_poll_fd = -1;
 }
 
 static void vfu_object_finalize(Object *obj)
-- 
2.20.1