[Qemu-devel] [PATCH v4 00/29] vhost-user reconnect fixes

[Qemu-devel] [PATCH v4 00/29] vhost-user reconnect fixes

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Hi,

Since 'vhost-user: simple reconnection support' was merged, it is
possible to disconnect and reconnect a vhost-user backend. However,
many code paths in qemu may trigger assert() when the backend is
disconnected.

Some assert() could simply be replaced by error_report() or silently
fail since they are recoverable cases. Some missing error checks can
also help prevent later issues. In many cases, the code assumes
get_vhost_net() will be non-NULL after a succesful connection, so I
changed it to stay after a disconnect until the new connection comes
(as suggested by Michael). There are also code paths that are wrong,
see "don't assume opaque is a fd" patch for an example.

Since there is feature checks on reconnection, qemu should wait for
the initial connection feature negotiation to complete. The test added
demonstrates this. Additionally, a regression was found during v2,
which could have been spotted with a multiqueue test, so add a basic
one that would have exhibited the issue.

For convenience, the series is also available on:
https://github.com/elmarco/qemu, branch vhost-user-reconnect

v4:
- change notify_migration_done() patch to be VHOST_BACKEND_TYPE_USER
  specific, to avoid having to handle the case where the backend
  doesn't implement the callback
- change vhost_dev_cleanup() to assert on empty log, instead of
  adding a call to vhost_log_put()
- made "keep vhost_net after a disconnection" more robust, got rid of
  the acked_features field
- improve commit log, and some patch reorganization for clarity

v3:
- add vhost-user multiqueue test, which would have helped to find the
  following fix
- fix waiting on vhost-user connection with multiqueue (found by
  Yuanhan Liu)
- merge vhost_user_{read,write}() error checking patches
- add error reporting to vhost_user_read() (similar to
  vhost_user_write())
- add a vhost_net_set_backend() wrapper to help with potential crash
- some leak fixes

v2:
- some patch ordering: minor fix, close(fd) fix,
  assert/fprintf->error_report, check and return error,
  vhost_dev_cleanup() fixes, keep vhost_net after a disconnect, wait
  until connection is ready
- merge read/write error checks
- do not rely on link state to check vhost-user init completed

Marc-André Lureau (29):
  misc: indentation
  vhost-user: minor simplification
  vhost: don't assume opaque is a fd, use backend cleanup
  vhost: make vhost_log_put() idempotent
  vhost: assert the log was cleaned up
  vhost: fix cleanup on not fully initialized device
  vhost: make vhost_dev_cleanup() idempotent
  vhost-net: always call vhost_dev_cleanup() on failure
  vhost: fix calling vhost_dev_cleanup() after vhost_dev_init()
  vhost: do not assert() on vhost_ops failure
  vhost: use error_report() instead of fprintf(stderr,...)
  qemu-char: fix qemu_chr_fe_set_msgfds() crash when disconnected
  vhost-user: call set_msgfds unconditionally
  vhost-user: check qemu_chr_fe_set_msgfds() return value
  vhost-user: check vhost_user_{read,write}() return value
  vhost-user: keep vhost_net after a disconnection
  vhost-user: add get_vhost_net() assertions
  Revert "vhost-net: do not crash if backend is not present"
  vhost-net: vhost_migration_done is vhost-user specific
  vhost: add assert() to check runtime behaviour
  char: add chr_wait_connected callback
  char: add and use tcp_chr_wait_connected
  vhost-user: wait until backend init is completed
  tests: plug some leaks in virtio-net-test
  tests: fix vhost-user-test leak
  tests: add /vhost-user/connect-fail test
  tests: add a simple /vhost-user/multiqueue test
  vhost-user: add error report in vhost_user_write()
  vhost: add vhost_net_set_backend()

 hw/net/vhost_net.c        |  34 ++++-------
 hw/virtio/vhost-user.c    |  67 ++++++++++++++-------
 hw/virtio/vhost.c         | 123 +++++++++++++++++++++++---------------
 include/hw/virtio/vhost.h |   4 ++
 include/sysemu/char.h     |   8 +++
 net/tap.c                 |   1 +
 net/vhost-user.c          |  60 +++++++++++--------
 qemu-char.c               |  82 ++++++++++++++++++--------
 tests/Makefile.include    |   2 +-
 tests/vhost-user-test.c   | 147 +++++++++++++++++++++++++++++++++++++++++++++-
 tests/virtio-net-test.c   |  12 +++-
 11 files changed, 396 insertions(+), 144 deletions(-)

-- 
2.9.0

[Qemu-devel] [PATCH v4 01/29] misc: indentation

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 50f4dcd..3f1fecc 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -313,7 +313,7 @@ int vhost_net_start(VirtIODevice *dev, NetClientState *ncs,
          * properly.
          */
         if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER) {
-                dev->use_guest_notifier_mask = false;
+            dev->use_guest_notifier_mask = false;
         }
      }
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 02/29] vhost-user: minor simplification

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Shorten the code and make it more clear by using the specialized
function g_str_has_prefix().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 net/vhost-user.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/net/vhost-user.c b/net/vhost-user.c
index 92f4cfd..18bd170 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -315,7 +315,6 @@ static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
 {
     const char *name = opaque;
     const char *driver, *netdev;
-    const char virtio_name[] = "virtio-net-";
 
     driver = qemu_opt_get(opts, "driver");
     netdev = qemu_opt_get(opts, "netdev");
@@ -325,7 +324,7 @@ static int net_vhost_check_net(void *opaque, QemuOpts *opts, Error **errp)
     }
 
     if (strcmp(netdev, name) == 0 &&
-        strncmp(driver, virtio_name, strlen(virtio_name)) != 0) {
+        !g_str_has_prefix(driver, "virtio-net-")) {
         error_setg(errp, "vhost-user requires frontend driver virtio-net-*");
         return -1;
     }
-- 
2.9.0

[Qemu-devel] [PATCH v4 03/29] vhost: don't assume opaque is a fd, use backend cleanup

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

vhost-dev opaque isn't necessarily an fd, it can be a chardev when using
vhost-user. Goto fail, so vhost_backend_cleanup() is called to handle
backend cleanup appropriately.

vhost_set_backend_type() should never fail, use an assert().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index a01394d..dbb4deb 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -997,21 +997,19 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
 
     hdev->migration_blocker = NULL;
 
-    if (vhost_set_backend_type(hdev, backend_type) < 0) {
-        close((uintptr_t)opaque);
-        return -1;
-    }
+    r = vhost_set_backend_type(hdev, backend_type);
+    assert(r >= 0);
 
-    if (hdev->vhost_ops->vhost_backend_init(hdev, opaque) < 0) {
-        close((uintptr_t)opaque);
-        return -errno;
+    r = hdev->vhost_ops->vhost_backend_init(hdev, opaque);
+    if (r < 0) {
+        goto fail;
     }
 
     if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
         fprintf(stderr, "vhost backend memory slots limit is less"
                 " than current number of present memory slots\n");
-        close((uintptr_t)opaque);
-        return -1;
+        r = -1;
+        goto fail;
     }
     QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 04/29] vhost: make vhost_log_put() idempotent

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Although not strictly required, it is nice to have vhost_log_put()
safely callable multiple times.

Clear dev->log* when calling vhost_log_put() to make the function
idempotent. This also simplifies a bit the caller work.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index dbb4deb..2753bb4 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -362,6 +362,8 @@ static void vhost_log_put(struct vhost_dev *dev, bool sync)
     if (!log) {
         return;
     }
+    dev->log = NULL;
+    dev->log_size = 0;
 
     --log->refcnt;
     if (log->refcnt == 0) {
@@ -710,8 +712,6 @@ static int vhost_migration_log(MemoryListener *listener, int enable)
             return r;
         }
         vhost_log_put(dev, false);
-        dev->log = NULL;
-        dev->log_size = 0;
     } else {
         vhost_dev_log_resize(dev, vhost_get_log_size(dev));
         r = vhost_dev_set_log(dev, true);
@@ -1290,7 +1290,4 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
 
     vhost_log_put(hdev, true);
     hdev->started = false;
-    hdev->log = NULL;
-    hdev->log_size = 0;
 }
-
-- 
2.9.0

[Qemu-devel] [PATCH v4 05/29] vhost: assert the log was cleaned up

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Make sure the log was released on cleanup, or it will leak (the
alternative is to call vhost_log_put() unconditionally, but it may hide
some dev state issues).

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 2753bb4..b229efd 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1096,6 +1096,7 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
     g_free(hdev->mem);
     g_free(hdev->mem_sections);
     hdev->vhost_ops->vhost_backend_cleanup(hdev);
+    assert(!hdev->log);
     QLIST_REMOVE(hdev, entry);
 }
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 06/29] vhost: fix cleanup on not fully initialized device

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

If vhost_dev_init() failed, caller may still call vhost_dev_cleanup()
later. However, vhost_dev_cleanup() tries to remove the device from the
list even if it wasn't yet added, which may lead to crashes. Similarly
for the memory listener.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index b229efd..08fb336 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1011,7 +1011,6 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
         r = -1;
         goto fail;
     }
-    QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
 
     r = hdev->vhost_ops->vhost_set_owner(hdev);
     if (r < 0) {
@@ -1070,6 +1069,7 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     hdev->started = false;
     hdev->memory_changed = false;
     memory_listener_register(&hdev->memory_listener, &address_space_memory);
+    QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
     return 0;
 fail_vq:
     while (--i >= 0) {
@@ -1088,7 +1088,11 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
     for (i = 0; i < hdev->nvqs; ++i) {
         vhost_virtqueue_cleanup(hdev->vqs + i);
     }
-    memory_listener_unregister(&hdev->memory_listener);
+    if (hdev->mem) {
+        /* those are only safe after successful init */
+        memory_listener_unregister(&hdev->memory_listener);
+        QLIST_REMOVE(hdev, entry);
+    }
     if (hdev->migration_blocker) {
         migrate_del_blocker(hdev->migration_blocker);
         error_free(hdev->migration_blocker);
@@ -1097,7 +1101,6 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
     g_free(hdev->mem_sections);
     hdev->vhost_ops->vhost_backend_cleanup(hdev);
     assert(!hdev->log);
-    QLIST_REMOVE(hdev, entry);
 }
 
 /* Stop processing guest IO notifications in qemu.
-- 
2.9.0

[Qemu-devel] [PATCH v4 07/29] vhost: make vhost_dev_cleanup() idempotent

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

It is called on multiple code path, so make it safe to call several
times (note: I don't remember a reproducer here, but a function called
'cleanup' should probably be idempotent in my book)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 08fb336..fa8d5f0 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1085,6 +1085,7 @@ fail:
 void vhost_dev_cleanup(struct vhost_dev *hdev)
 {
     int i;
+
     for (i = 0; i < hdev->nvqs; ++i) {
         vhost_virtqueue_cleanup(hdev->vqs + i);
     }
@@ -1099,8 +1100,12 @@ void vhost_dev_cleanup(struct vhost_dev *hdev)
     }
     g_free(hdev->mem);
     g_free(hdev->mem_sections);
-    hdev->vhost_ops->vhost_backend_cleanup(hdev);
+    if (hdev->vhost_ops) {
+        hdev->vhost_ops->vhost_backend_cleanup(hdev);
+    }
     assert(!hdev->log);
+
+    memset(hdev, 0, sizeof(struct vhost_dev));
 }
 
 /* Stop processing guest IO notifications in qemu.
-- 
2.9.0

[Qemu-devel] [PATCH v4 08/29] vhost-net: always call vhost_dev_cleanup() on failure

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

vhost_dev_init(), calling vhost backend initialization, should be
cleaned up after failure too. Call vhost_dev_cleanup() in all failure
cases. First, it needs to zero-alloc the struct to avoid the initial
garbage.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 3f1fecc..1da05d0 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -140,7 +140,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
 {
     int r;
     bool backend_kernel = options->backend_type == VHOST_BACKEND_TYPE_KERNEL;
-    struct vhost_net *net = g_malloc(sizeof *net);
+    struct vhost_net *net = g_new0(struct vhost_net, 1);
     uint64_t features = 0;
 
     if (!options->net_backend) {
@@ -185,7 +185,6 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
             fprintf(stderr, "vhost lacks feature mask %" PRIu64
                    " for backend\n",
                    (uint64_t)(~net->dev.features & net->dev.backend_features));
-            vhost_dev_cleanup(&net->dev);
             goto fail;
         }
     }
@@ -197,7 +196,6 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
             fprintf(stderr, "vhost lacks feature mask %" PRIu64
                     " for backend\n",
                     (uint64_t)(~net->dev.features & features));
-            vhost_dev_cleanup(&net->dev);
             goto fail;
         }
     }
@@ -205,7 +203,9 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
     vhost_net_ack_features(net, features);
 
     return net;
+
 fail:
+    vhost_dev_cleanup(&net->dev);
     g_free(net);
     return NULL;
 }
-- 
2.9.0

[Qemu-devel] [PATCH v4 09/29] vhost: fix calling vhost_dev_cleanup() after vhost_dev_init()

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

vhost_net_init() calls vhost_dev_init() and in case of failure, calls
vhost_dev_cleanup() directly. However, the structure is already
partially cleaned on error. Calling vhost_dev_cleanup() again will call
vhost_virtqueue_cleanup() on already clean queues, and causing potential
double-close. Instead, adjust dev->nvqs and simplify vhost_dev_init()
code to call vhost_virtqueue_cleanup().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index fa8d5f0..63954a0 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1025,7 +1025,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     for (i = 0; i < hdev->nvqs; ++i) {
         r = vhost_virtqueue_init(hdev, hdev->vqs + i, hdev->vq_index + i);
         if (r < 0) {
-            goto fail_vq;
+            hdev->nvqs = i;
+            goto fail;
         }
     }
     hdev->features = features;
@@ -1071,14 +1072,9 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     memory_listener_register(&hdev->memory_listener, &address_space_memory);
     QLIST_INSERT_HEAD(&vhost_devices, hdev, entry);
     return 0;
-fail_vq:
-    while (--i >= 0) {
-        vhost_virtqueue_cleanup(hdev->vqs + i);
-    }
+
 fail:
-    r = -errno;
-    hdev->vhost_ops->vhost_backend_cleanup(hdev);
-    QLIST_REMOVE(hdev, entry);
+    vhost_dev_cleanup(hdev);
     return r;
 }
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 10/29] vhost: do not assert() on vhost_ops failure

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Calling a vhost operation may fail, for example with disconnected
vhost-user backend, but qemu shouldn't abort in this case.

Report an error instead, except on error/cleanup code path.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 63954a0..dd03900 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -400,7 +400,10 @@ static inline void vhost_dev_log_resize(struct vhost_dev *dev, uint64_t size)
     /* inform backend of log switching, this must be done before
        releasing the current log, to ensure no logging is lost */
     r = dev->vhost_ops->vhost_set_log_base(dev, log_base, log);
-    assert(r >= 0);
+    if (r < 0) {
+        error_report("Failed to change backend log");
+    }
+
     vhost_log_put(dev, true);
     dev->log = log;
     dev->log_size = size;
@@ -567,7 +570,9 @@ static void vhost_commit(MemoryListener *listener)
 
     if (!dev->log_enabled) {
         r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem);
-        assert(r >= 0);
+        if (r < 0) {
+            error_report("Failed to set mem table");
+        }
         dev->memory_changed = false;
         return;
     }
@@ -580,7 +585,9 @@ static void vhost_commit(MemoryListener *listener)
         vhost_dev_log_resize(dev, log_size + VHOST_LOG_BUFFER);
     }
     r = dev->vhost_ops->vhost_set_mem_table(dev, dev->mem);
-    assert(r >= 0);
+    if (r < 0) {
+        error_report("Failed to set mem table");
+    }
     /* To log less, can only decrease log size after table update. */
     if (dev->log_size > log_size + VHOST_LOG_BUFFER) {
         vhost_dev_log_resize(dev, log_size);
@@ -649,6 +656,7 @@ static int vhost_virtqueue_set_addr(struct vhost_dev *dev,
     };
     int r = dev->vhost_ops->vhost_set_vring_addr(dev, &addr);
     if (r < 0) {
+        error_report("Failed to set vring addr");
         return -errno;
     }
     return 0;
@@ -662,12 +670,15 @@ static int vhost_dev_set_features(struct vhost_dev *dev, bool enable_log)
         features |= 0x1ULL << VHOST_F_LOG_ALL;
     }
     r = dev->vhost_ops->vhost_set_features(dev, features);
+    if (r < 0) {
+        error_report("Failed to set features");
+    }
     return r < 0 ? -errno : 0;
 }
 
 static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 {
-    int r, t, i, idx;
+    int r, i, idx;
     r = vhost_dev_set_features(dev, enable_log);
     if (r < 0) {
         goto err_features;
@@ -684,12 +695,10 @@ static int vhost_dev_set_log(struct vhost_dev *dev, bool enable_log)
 err_vq:
     for (; i >= 0; --i) {
         idx = dev->vhost_ops->vhost_get_vq_index(dev, dev->vq_index + i);
-        t = vhost_virtqueue_set_addr(dev, dev->vqs + i, idx,
-                                     dev->log_enabled);
-        assert(t >= 0);
+        vhost_virtqueue_set_addr(dev, dev->vqs + i, idx,
+                                 dev->log_enabled);
     }
-    t = vhost_dev_set_features(dev, dev->log_enabled);
-    assert(t >= 0);
+    vhost_dev_set_features(dev, dev->log_enabled);
 err_features:
     return r;
 }
@@ -937,7 +946,6 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
         }
     }
 
-    assert (r >= 0);
     cpu_physical_memory_unmap(vq->ring, virtio_queue_get_ring_size(vdev, idx),
                               0, virtio_queue_get_ring_size(vdev, idx));
     cpu_physical_memory_unmap(vq->used, virtio_queue_get_used_size(vdev, idx),
@@ -1191,7 +1199,9 @@ void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
 
     file.index = hdev->vhost_ops->vhost_get_vq_index(hdev, n);
     r = hdev->vhost_ops->vhost_set_vring_call(hdev, &file);
-    assert(r >= 0);
+    if (r < 0) {
+        error_report("Failed to set vring call");
+    }
 }
 
 uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
-- 
2.9.0

[Qemu-devel] [PATCH v4 11/29] vhost: use error_report() instead of fprintf(stderr, ...)

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Let's use qemu proper error reporting API, this ensures the error is
reported at the right place (stderr or monitor), with a conventional
format.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index dd03900..6b4ddef 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -427,11 +427,11 @@ static int vhost_verify_ring_mappings(struct vhost_dev *dev,
         l = vq->ring_size;
         p = cpu_physical_memory_map(vq->ring_phys, &l, 1);
         if (!p || l != vq->ring_size) {
-            fprintf(stderr, "Unable to map ring buffer for ring %d\n", i);
+            error_report("Unable to map ring buffer for ring %d", i);
             r = -ENOMEM;
         }
         if (p != vq->ring) {
-            fprintf(stderr, "Ring buffer relocated for ring %d\n", i);
+            error_report("Ring buffer relocated for ring %d", i);
             r = -EBUSY;
         }
         cpu_physical_memory_unmap(p, l, 0, 0);
@@ -928,8 +928,7 @@ static void vhost_virtqueue_stop(struct vhost_dev *dev,
 
     r = dev->vhost_ops->vhost_get_vring_base(dev, &state);
     if (r < 0) {
-        fprintf(stderr, "vhost VQ %d ring restore failed: %d\n", idx, r);
-        fflush(stderr);
+        error_report("vhost VQ %d ring restore failed: %d", idx, r);
     }
     virtio_queue_set_last_avail_idx(vdev, idx, state.num);
     virtio_queue_invalidate_signalled_used(vdev, idx);
@@ -1014,8 +1013,8 @@ int vhost_dev_init(struct vhost_dev *hdev, void *opaque,
     }
 
     if (used_memslots > hdev->vhost_ops->vhost_backend_memslots_limit(hdev)) {
-        fprintf(stderr, "vhost backend memory slots limit is less"
-                " than current number of present memory slots\n");
+        error_report("vhost backend memory slots limit is less"
+                " than current number of present memory slots");
         r = -1;
         goto fail;
     }
@@ -1121,8 +1120,9 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
     VirtioBusState *vbus = VIRTIO_BUS(qbus);
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(vbus);
     int i, r, e;
+
     if (!k->ioeventfd_started) {
-        fprintf(stderr, "binding does not support host notifiers\n");
+        error_report("binding does not support host notifiers");
         r = -ENOSYS;
         goto fail;
     }
@@ -1131,7 +1131,7 @@ int vhost_dev_enable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
         r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i,
                                          true);
         if (r < 0) {
-            fprintf(stderr, "vhost VQ %d notifier binding failed: %d\n", i, -r);
+            error_report("vhost VQ %d notifier binding failed: %d", i, -r);
             goto fail_vq;
         }
     }
@@ -1142,8 +1142,7 @@ fail_vq:
         e = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i,
                                          false);
         if (e < 0) {
-            fprintf(stderr, "vhost VQ %d notifier cleanup error: %d\n", i, -r);
-            fflush(stderr);
+            error_report("vhost VQ %d notifier cleanup error: %d", i, -r);
         }
         assert (e >= 0);
     }
@@ -1165,8 +1164,7 @@ void vhost_dev_disable_notifiers(struct vhost_dev *hdev, VirtIODevice *vdev)
         r = virtio_bus_set_host_notifier(VIRTIO_BUS(qbus), hdev->vq_index + i,
                                          false);
         if (r < 0) {
-            fprintf(stderr, "vhost VQ %d notifier cleanup failed: %d\n", i, -r);
-            fflush(stderr);
+            error_report("vhost VQ %d notifier cleanup failed: %d", i, -r);
         }
         assert (r >= 0);
     }
-- 
2.9.0

[Qemu-devel] [PATCH v4 12/29] qemu-char: fix qemu_chr_fe_set_msgfds() crash when disconnected

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Calling qemu_chr_fe_set_msgfds() on unconnected socket leads to crash
since s->ioc is NULL in this case. Return an error earlier instead.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 qemu-char.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 0698b98..c4fa779 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -2760,14 +2760,16 @@ static int tcp_set_msgfds(CharDriverState *chr, int *fds, int num)
 {
     TCPCharDriver *s = chr->opaque;
 
-    if (!qio_channel_has_feature(s->ioc,
-                                 QIO_CHANNEL_FEATURE_FD_PASS)) {
-        return -1;
-    }
     /* clear old pending fd array */
     g_free(s->write_msgfds);
     s->write_msgfds = NULL;
 
+    if (!s->connected ||
+        !qio_channel_has_feature(s->ioc,
+                                 QIO_CHANNEL_FEATURE_FD_PASS)) {
+        return -1;
+    }
+
     if (num) {
         s->write_msgfds = g_new(int, num);
         memcpy(s->write_msgfds, fds, num * sizeof(int));
-- 
2.9.0

[Qemu-devel] [PATCH v4 13/29] vhost-user: call set_msgfds unconditionally

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

It is fine to call set_msgfds() with 0 fd, and ensures any previous fd
array is cleared.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost-user.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 495e09f..f01b92f 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -187,9 +187,7 @@ static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg,
         return 0;
     }
 
-    if (fd_num) {
-        qemu_chr_fe_set_msgfds(chr, fds, fd_num);
-    }
+    qemu_chr_fe_set_msgfds(chr, fds, fd_num);
 
     return qemu_chr_fe_write_all(chr, (const uint8_t *) msg, size) == size ?
             0 : -1;
-- 
2.9.0

[Qemu-devel] [PATCH v4 14/29] vhost-user: check qemu_chr_fe_set_msgfds() return value

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Check qemu_chr_fe_set_msgfds() for errors, to make sure the message to
be sent is correct.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost-user.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index f01b92f..5dae496 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -187,7 +187,9 @@ static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg,
         return 0;
     }
 
-    qemu_chr_fe_set_msgfds(chr, fds, fd_num);
+    if (qemu_chr_fe_set_msgfds(chr, fds, fd_num) < 0) {
+        return -1;
+    }
 
     return qemu_chr_fe_write_all(chr, (const uint8_t *) msg, size) == size ?
             0 : -1;
-- 
2.9.0

[Qemu-devel] [PATCH v4 15/29] vhost-user: check vhost_user_{read, write}() return value

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

The vhost-user code is quite inconsistent with error handling. Instead
of ignoring some return values of read/write and silently going on with
invalid state (invalid read for example), break the code flow when the
error happened.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost-user.c | 50 ++++++++++++++++++++++++++++++++++----------------
 1 file changed, 34 insertions(+), 16 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 5dae496..819481d 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -214,12 +214,14 @@ static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
         fds[fd_num++] = log->fd;
     }
 
-    vhost_user_write(dev, &msg, fds, fd_num);
+    if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
+        return -1;
+    }
 
     if (shmfd) {
         msg.size = 0;
         if (vhost_user_read(dev, &msg) < 0) {
-            return 0;
+            return -1;
         }
 
         if (msg.request != VHOST_USER_SET_LOG_BASE) {
@@ -275,7 +277,9 @@ static int vhost_user_set_mem_table(struct vhost_dev *dev,
     msg.size += sizeof(msg.payload.memory.padding);
     msg.size += fd_num * sizeof(VhostUserMemoryRegion);
 
-    vhost_user_write(dev, &msg, fds, fd_num);
+    if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -290,7 +294,9 @@ static int vhost_user_set_vring_addr(struct vhost_dev *dev,
         .size = sizeof(msg.payload.addr),
     };
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -313,7 +319,9 @@ static int vhost_set_vring(struct vhost_dev *dev,
         .size = sizeof(msg.payload.state),
     };
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -360,10 +368,12 @@ static int vhost_user_get_vring_base(struct vhost_dev *dev,
         .size = sizeof(msg.payload.state),
     };
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     if (vhost_user_read(dev, &msg) < 0) {
-        return 0;
+        return -1;
     }
 
     if (msg.request != VHOST_USER_GET_VRING_BASE) {
@@ -401,7 +411,9 @@ static int vhost_set_vring_file(struct vhost_dev *dev,
         msg.payload.u64 |= VHOST_USER_VRING_NOFD_MASK;
     }
 
-    vhost_user_write(dev, &msg, fds, fd_num);
+    if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -427,7 +439,9 @@ static int vhost_user_set_u64(struct vhost_dev *dev, int request, uint64_t u64)
         .size = sizeof(msg.payload.u64),
     };
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -455,10 +469,12 @@ static int vhost_user_get_u64(struct vhost_dev *dev, int request, uint64_t *u64)
         return 0;
     }
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     if (vhost_user_read(dev, &msg) < 0) {
-        return 0;
+        return -1;
     }
 
     if (msg.request != request) {
@@ -489,7 +505,9 @@ static int vhost_user_set_owner(struct vhost_dev *dev)
         .flags = VHOST_USER_VERSION,
     };
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -501,7 +519,9 @@ static int vhost_user_reset_device(struct vhost_dev *dev)
         .flags = VHOST_USER_VERSION,
     };
 
-    vhost_user_write(dev, &msg, NULL, 0);
+    if (vhost_user_write(dev, &msg, NULL, 0) < 0) {
+        return -1;
+    }
 
     return 0;
 }
@@ -588,7 +608,6 @@ static bool vhost_user_requires_shm_log(struct vhost_dev *dev)
 static int vhost_user_migration_done(struct vhost_dev *dev, char* mac_addr)
 {
     VhostUserMsg msg = { 0 };
-    int err;
 
     assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
 
@@ -605,8 +624,7 @@ static int vhost_user_migration_done(struct vhost_dev *dev, char* mac_addr)
         memcpy((char *)&msg.payload.u64, mac_addr, 6);
         msg.size = sizeof(msg.payload.u64);
 
-        err = vhost_user_write(dev, &msg, NULL, 0);
-        return err;
+        return vhost_user_write(dev, &msg, NULL, 0);
     }
     return -1;
 }
-- 
2.9.0

[Qemu-devel] [PATCH v4 16/29] vhost-user: keep vhost_net after a disconnection

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Many code paths assume get_vhost_net() returns non-null.

Keep VhostUserState.vhost_net after a successful vhost_net_init(),
instead of freeing it in vhost_net_cleanup().

VhostUserState.vhost_net is thus freed before after being recreated or
on final vhost_user_cleanup() and there is no need to save the acked
features.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c |  1 -
 net/tap.c          |  1 +
 net/vhost-user.c   | 37 +++++++++++++++++--------------------
 3 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 1da05d0..08c7d1e 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -378,7 +378,6 @@ void vhost_net_stop(VirtIODevice *dev, NetClientState *ncs,
 void vhost_net_cleanup(struct vhost_net *net)
 {
     vhost_dev_cleanup(&net->dev);
-    g_free(net);
 }
 
 int vhost_net_notify_migration_done(struct vhost_net *net, char* mac_addr)
diff --git a/net/tap.c b/net/tap.c
index 49817c7..31726e7 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -299,6 +299,7 @@ static void tap_cleanup(NetClientState *nc)
 
     if (s->vhost_net) {
         vhost_net_cleanup(s->vhost_net);
+        g_free(s->vhost_net);
         s->vhost_net = NULL;
     }
 
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 18bd170..a80f008 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -23,7 +23,6 @@ typedef struct VhostUserState {
     CharDriverState *chr;
     VHostNetState *vhost_net;
     guint watch;
-    uint64_t acked_features;
 } VhostUserState;
 
 typedef struct VhostUserChardevProps {
@@ -42,12 +41,7 @@ uint64_t vhost_user_get_acked_features(NetClientState *nc)
 {
     VhostUserState *s = DO_UPCAST(VhostUserState, nc, nc);
     assert(nc->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
-    return s->acked_features;
-}
-
-static int vhost_user_running(VhostUserState *s)
-{
-    return (s->vhost_net) ? 1 : 0;
+    return s->vhost_net ? vhost_net_get_acked_features(s->vhost_net) : 0;
 }
 
 static void vhost_user_stop(int queues, NetClientState *ncs[])
@@ -59,15 +53,9 @@ static void vhost_user_stop(int queues, NetClientState *ncs[])
         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
 
         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
-        if (!vhost_user_running(s)) {
-            continue;
-        }
 
         if (s->vhost_net) {
-            /* save acked features */
-            s->acked_features = vhost_net_get_acked_features(s->vhost_net);
             vhost_net_cleanup(s->vhost_net);
-            s->vhost_net = NULL;
         }
     }
 }
@@ -75,6 +63,7 @@ static void vhost_user_stop(int queues, NetClientState *ncs[])
 static int vhost_user_start(int queues, NetClientState *ncs[])
 {
     VhostNetOptions options;
+    struct vhost_net *net = NULL;
     VhostUserState *s;
     int max_queues;
     int i;
@@ -85,32 +74,39 @@ static int vhost_user_start(int queues, NetClientState *ncs[])
         assert (ncs[i]->info->type == NET_CLIENT_OPTIONS_KIND_VHOST_USER);
 
         s = DO_UPCAST(VhostUserState, nc, ncs[i]);
-        if (vhost_user_running(s)) {
-            continue;
-        }
 
         options.net_backend = ncs[i];
         options.opaque      = s->chr;
-        s->vhost_net = vhost_net_init(&options);
-        if (!s->vhost_net) {
+
+        net = vhost_net_init(&options);
+        if (!net) {
             error_report("failed to init vhost_net for queue %d", i);
             goto err;
         }
 
         if (i == 0) {
-            max_queues = vhost_net_get_max_queues(s->vhost_net);
+            max_queues = vhost_net_get_max_queues(net);
             if (queues > max_queues) {
                 error_report("you are asking more queues than supported: %d",
                              max_queues);
                 goto err;
             }
         }
+
+        if (s->vhost_net) {
+            vhost_net_cleanup(s->vhost_net);
+            g_free(s->vhost_net);
+        }
+        s->vhost_net = net;
     }
 
     return 0;
 
 err:
-    vhost_user_stop(i + 1, ncs);
+    if (net) {
+        vhost_net_cleanup(net);
+    }
+    vhost_user_stop(i, ncs);
     return -1;
 }
 
@@ -149,6 +145,7 @@ static void vhost_user_cleanup(NetClientState *nc)
 
     if (s->vhost_net) {
         vhost_net_cleanup(s->vhost_net);
+        g_free(s->vhost_net);
         s->vhost_net = NULL;
     }
     if (s->chr) {
-- 
2.9.0

[Qemu-devel] [PATCH v4 17/29] vhost-user: add get_vhost_net() assertions

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Add a few assertions to be more explicit about the runtime behaviour
after the previous patch: get_vhost_net() is non-null after
net_vhost_user_init().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c | 1 +
 net/vhost-user.c   | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 08c7d1e..473e6e5 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -417,6 +417,7 @@ VHostNetState *get_vhost_net(NetClientState *nc)
         break;
     case NET_CLIENT_OPTIONS_KIND_VHOST_USER:
         vhost_net = vhost_user_get_vhost_net(nc);
+        assert(vhost_net != NULL);
         break;
     default:
         break;
diff --git a/net/vhost-user.c b/net/vhost-user.c
index a80f008..2442925 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -257,6 +257,8 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
 
     qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
 
+    assert(s->vhost_net != NULL);
+
     return 0;
 }
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 18/29] Revert "vhost-net: do not crash if backend is not present"

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Now that get_vhost_net() returns non-null after a successful
vhost_net_init(), we no longer need to check this case.

This reverts commit ecd34898596c60f79886061618dd7e01001113ad.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 473e6e5..22ea653 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -429,15 +429,10 @@ VHostNetState *get_vhost_net(NetClientState *nc)
 int vhost_set_vring_enable(NetClientState *nc, int enable)
 {
     VHostNetState *net = get_vhost_net(nc);
-    const VhostOps *vhost_ops;
+    const VhostOps *vhost_ops = net->dev.vhost_ops;
 
     nc->vring_enable = enable;
 
-    if (!net) {
-        return 0;
-    }
-
-    vhost_ops = net->dev.vhost_ops;
     if (vhost_ops->vhost_set_vring_enable) {
         return vhost_ops->vhost_set_vring_enable(&net->dev, enable);
     }
-- 
2.9.0

[Qemu-devel] [PATCH v4 19/29] vhost-net: vhost_migration_done is vhost-user specific

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Either the callback is mandatory to implement, in which case an assert()
is more appropriate, or it's not and we can't tell much whether the
function should fail or not (given it's name, I guess it should silently
success by default). Instead, make the implementation mandatory and
vhost-user specific to be more clear about its usage.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 22ea653..a8ffcb2 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -383,13 +383,11 @@ void vhost_net_cleanup(struct vhost_net *net)
 int vhost_net_notify_migration_done(struct vhost_net *net, char* mac_addr)
 {
     const VhostOps *vhost_ops = net->dev.vhost_ops;
-    int r = -1;
 
-    if (vhost_ops->vhost_migration_done) {
-        r = vhost_ops->vhost_migration_done(&net->dev, mac_addr);
-    }
+    assert(vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+    assert(vhost_ops->vhost_migration_done);
 
-    return r;
+    return vhost_ops->vhost_migration_done(&net->dev, mac_addr);
 }
 
 bool vhost_net_virtqueue_pending(VHostNetState *net, int idx)
-- 
2.9.0

[Qemu-devel] [PATCH v4 20/29] vhost: add assert() to check runtime behaviour

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

All these functions must be called only after the backend is connected.
They are called from virtio-net.c, after either virtio or link status
change.

The check for nc->peer->link_down should ensure vhost_net_{start,stop}()
are always called between vhost_user_{start,stop}().

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 6b4ddef..3688236 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1188,6 +1188,9 @@ void vhost_virtqueue_mask(struct vhost_dev *hdev, VirtIODevice *vdev, int n,
     int r, index = n - hdev->vq_index;
     struct vhost_vring_file file;
 
+    /* should only be called after backend is connected */
+    assert(hdev->vhost_ops != NULL);
+
     if (mask) {
         assert(vdev->use_guest_notifier_mask);
         file.fd = event_notifier_get_fd(&hdev->vqs[index].masked_notifier);
@@ -1234,6 +1237,9 @@ int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev)
 {
     int i, r;
 
+    /* should only be called after backend is connected */
+    assert(hdev->vhost_ops != NULL);
+
     hdev->started = true;
 
     r = vhost_dev_set_features(hdev, hdev->log_enabled);
@@ -1294,6 +1300,9 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
 {
     int i;
 
+    /* should only be called after backend is connected */
+    assert(hdev->vhost_ops != NULL);
+
     for (i = 0; i < hdev->nvqs; ++i) {
         vhost_virtqueue_stop(hdev,
                              vdev,
-- 
2.9.0

[Qemu-devel] [PATCH v4 21/29] char: add chr_wait_connected callback

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

A function to wait on the backend to be connected, to be used in the
following patches.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 include/sysemu/char.h | 8 ++++++++
 qemu-char.c           | 9 +++++++++
 2 files changed, 17 insertions(+)

diff --git a/include/sysemu/char.h b/include/sysemu/char.h
index 57df10a..15aa8ee 100644
--- a/include/sysemu/char.h
+++ b/include/sysemu/char.h
@@ -70,6 +70,7 @@ struct CharDriverState {
     int (*get_msgfds)(struct CharDriverState *s, int* fds, int num);
     int (*set_msgfds)(struct CharDriverState *s, int *fds, int num);
     int (*chr_add_client)(struct CharDriverState *chr, int fd);
+    int (*chr_wait_connected)(struct CharDriverState *chr, Error **errp);
     IOEventHandler *chr_event;
     IOCanReadHandler *chr_can_read;
     IOReadHandler *chr_read;
@@ -151,6 +152,13 @@ CharDriverState *qemu_chr_new(const char *label, const char *filename,
  */
 void qemu_chr_disconnect(CharDriverState *chr);
 
+/**
+ * @qemu_chr_wait_connected:
+ *
+ * Wait for characted backend to be connected.
+ */
+int qemu_chr_wait_connected(CharDriverState *chr, Error **errp);
+
 /**
  * @qemu_chr_new_noreplay:
  *
diff --git a/qemu-char.c b/qemu-char.c
index c4fa779..1daadc1 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3139,6 +3139,15 @@ static gboolean tcp_chr_accept(QIOChannel *channel,
     return TRUE;
 }
 
+int qemu_chr_wait_connected(CharDriverState *chr, Error **errp)
+{
+    if (chr->chr_wait_connected) {
+        return chr->chr_wait_connected(chr, errp);
+    }
+
+    return 0;
+}
+
 static void tcp_chr_close(CharDriverState *chr)
 {
     TCPCharDriver *s = chr->opaque;
-- 
2.9.0

[Qemu-devel] [PATCH v4 22/29] char: add and use tcp_chr_wait_connected

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Add a chr_wait_connected for the tcp backend, and use it in the
open_socket() function.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 qemu-char.c | 63 ++++++++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 44 insertions(+), 19 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 1daadc1..da7ea26 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -3139,6 +3139,32 @@ static gboolean tcp_chr_accept(QIOChannel *channel,
     return TRUE;
 }
 
+static int tcp_chr_wait_connected(CharDriverState *chr, Error **errp)
+{
+    TCPCharDriver *s = chr->opaque;
+    QIOChannelSocket *sioc;
+
+    while (!s->connected) {
+        if (s->is_listen) {
+            fprintf(stderr, "QEMU waiting for connection on: %s\n",
+                    chr->filename);
+            qio_channel_set_blocking(QIO_CHANNEL(s->listen_ioc), true, NULL);
+            tcp_chr_accept(QIO_CHANNEL(s->listen_ioc), G_IO_IN, chr);
+            qio_channel_set_blocking(QIO_CHANNEL(s->listen_ioc), false, NULL);
+        } else {
+            sioc = qio_channel_socket_new();
+            if (qio_channel_socket_connect_sync(sioc, s->addr, errp) < 0) {
+                object_unref(OBJECT(sioc));
+                return -1;
+            }
+            tcp_chr_new_client(chr, sioc);
+            object_unref(OBJECT(sioc));
+        }
+    }
+
+    return 0;
+}
+
 int qemu_chr_wait_connected(CharDriverState *chr, Error **errp)
 {
     if (chr->chr_wait_connected) {
@@ -4402,6 +4428,7 @@ static CharDriverState *qmp_chardev_open_socket(const char *id,
     s->addr = QAPI_CLONE(SocketAddress, sock->addr);
 
     chr->opaque = s;
+    chr->chr_wait_connected = tcp_chr_wait_connected;
     chr->chr_write = tcp_chr_write;
     chr->chr_sync_read = tcp_chr_sync_read;
     chr->chr_close = tcp_chr_close;
@@ -4425,32 +4452,30 @@ static CharDriverState *qmp_chardev_open_socket(const char *id,
         s->reconnect_time = reconnect;
     }
 
-    sioc = qio_channel_socket_new();
     if (s->reconnect_time) {
+        sioc = qio_channel_socket_new();
         qio_channel_socket_connect_async(sioc, s->addr,
                                          qemu_chr_socket_connected,
                                          chr, NULL);
-    } else if (s->is_listen) {
-        if (qio_channel_socket_listen_sync(sioc, s->addr, errp) < 0) {
-            goto error;
-        }
-        s->listen_ioc = sioc;
-        if (is_waitconnect) {
-            fprintf(stderr, "QEMU waiting for connection on: %s\n",
-                    chr->filename);
-            tcp_chr_accept(QIO_CHANNEL(s->listen_ioc), G_IO_IN, chr);
-        }
-        qio_channel_set_blocking(QIO_CHANNEL(s->listen_ioc), false, NULL);
-        if (!s->ioc) {
-            s->listen_tag = qio_channel_add_watch(
-                QIO_CHANNEL(s->listen_ioc), G_IO_IN, tcp_chr_accept, chr, NULL);
-        }
     } else {
-        if (qio_channel_socket_connect_sync(sioc, s->addr, errp) < 0) {
+        if (s->is_listen) {
+            sioc = qio_channel_socket_new();
+            if (qio_channel_socket_listen_sync(sioc, s->addr, errp) < 0) {
+                goto error;
+            }
+            s->listen_ioc = sioc;
+            if (is_waitconnect &&
+                qemu_chr_wait_connected(chr, errp) < 0) {
+                goto error;
+            }
+            if (!s->ioc) {
+                s->listen_tag = qio_channel_add_watch(
+                    QIO_CHANNEL(s->listen_ioc), G_IO_IN,
+                    tcp_chr_accept, chr, NULL);
+            }
+        } else if (qemu_chr_wait_connected(chr, errp) < 0) {
             goto error;
         }
-        tcp_chr_new_client(chr, sioc);
-        object_unref(OBJECT(sioc));
     }
 
     return chr;
-- 
2.9.0

[Qemu-devel] [PATCH v4 23/29] vhost-user: wait until backend init is completed

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

The chardev waits for an initial connection before starting qemu, and
vhost-user should wait for the backend negotiation to be completed
before starting qemu too.

vhost-user is started in the net_vhost_user_event callback, which is
synchronously called after the socket is connected. Use a
VhostUserState.started flag to indicate vhost-user init completed
successfully and qemu can be started.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 net/vhost-user.c | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/net/vhost-user.c b/net/vhost-user.c
index 2442925..207da94 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -23,6 +23,7 @@ typedef struct VhostUserState {
     CharDriverState *chr;
     VHostNetState *vhost_net;
     guint watch;
+    bool started;
 } VhostUserState;
 
 typedef struct VhostUserChardevProps {
@@ -218,6 +219,7 @@ static void net_vhost_user_event(void *opaque, int event)
             return;
         }
         qmp_set_link(name, true, &err);
+        s->started = true;
         break;
     case CHR_EVENT_CLOSED:
         qmp_set_link(name, false, &err);
@@ -236,7 +238,7 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
                                const char *name, CharDriverState *chr,
                                int queues)
 {
-    NetClientState *nc;
+    NetClientState *nc, *nc0 = NULL;
     VhostUserState *s;
     int i;
 
@@ -245,6 +247,9 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
 
     for (i = 0; i < queues; i++) {
         nc = qemu_new_net_client(&net_vhost_user_info, peer, device, name);
+        if (!nc0) {
+            nc0 = nc;
+        }
 
         snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
                  i, chr->label);
@@ -255,7 +260,16 @@ static int net_vhost_user_init(NetClientState *peer, const char *device,
         s->chr = chr;
     }
 
-    qemu_chr_add_handlers(chr, NULL, NULL, net_vhost_user_event, nc[0].name);
+    s = DO_UPCAST(VhostUserState, nc, nc0);
+    do {
+        Error *err = NULL;
+        if (qemu_chr_wait_connected(chr, &err) < 0) {
+            error_report_err(err);
+            return -1;
+        }
+        qemu_chr_add_handlers(chr, NULL, NULL,
+                              net_vhost_user_event, nc0->name);
+    } while (!s->started);
 
     assert(s->vhost_net != NULL);
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 24/29] tests: plug some leaks in virtio-net-test

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Found thanks to valgrind.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 tests/virtio-net-test.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/tests/virtio-net-test.c b/tests/virtio-net-test.c
index a34a939..361506f 100644
--- a/tests/virtio-net-test.c
+++ b/tests/virtio-net-test.c
@@ -149,6 +149,7 @@ static void rx_stop_cont_test(const QVirtioBus *bus, QVirtioDevice *dev,
     char test[] = "TEST";
     char buffer[64];
     int len = htonl(sizeof(test));
+    QDict *rsp;
     struct iovec iov[] = {
         {
             .iov_base = &len,
@@ -165,7 +166,8 @@ static void rx_stop_cont_test(const QVirtioBus *bus, QVirtioDevice *dev,
     free_head = qvirtqueue_add(vq, req_addr, 64, true, false);
     qvirtqueue_kick(bus, dev, vq, free_head);
 
-    qmp("{ 'execute' : 'stop'}");
+    rsp = qmp("{ 'execute' : 'stop'}");
+    QDECREF(rsp);
 
     ret = iov_send(socket, iov, 2, 0, sizeof(len) + sizeof(test));
     g_assert_cmpint(ret, ==, sizeof(test) + sizeof(len));
@@ -173,8 +175,10 @@ static void rx_stop_cont_test(const QVirtioBus *bus, QVirtioDevice *dev,
     /* We could check the status, but this command is more importantly to
      * ensure the packet data gets queued in QEMU, before we do 'cont'.
      */
-    qmp("{ 'execute' : 'query-status'}");
-    qmp("{ 'execute' : 'cont'}");
+    rsp = qmp("{ 'execute' : 'query-status'}");
+    QDECREF(rsp);
+    rsp = qmp("{ 'execute' : 'cont'}");
+    QDECREF(rsp);
 
     qvirtio_wait_queue_isr(bus, dev, vq, QVIRTIO_NET_TIMEOUT_US);
     memread(req_addr + VNET_HDR_SIZE, buffer, sizeof(test));
@@ -230,8 +234,10 @@ static void pci_basic(gconstpointer data)
     /* End test */
     close(sv[0]);
     qvirtqueue_cleanup(&qvirtio_pci, &tx->vq, alloc);
+    qvirtqueue_cleanup(&qvirtio_pci, &rx->vq, alloc);
     pc_alloc_uninit(alloc);
     qvirtio_pci_device_disable(dev);
+    g_free(dev->pdev);
     g_free(dev);
     qpci_free_pc(bus);
     test_end();
-- 
2.9.0

[Qemu-devel] [PATCH v4 25/29] tests: fix vhost-user-test leak

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Spotted by valgrind.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 tests/vhost-user-test.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
index 421d432..a0b91ab 100644
--- a/tests/vhost-user-test.c
+++ b/tests/vhost-user-test.c
@@ -683,6 +683,7 @@ static void test_reconnect(void)
                                   qtest_get_arch());
     g_test_trap_subprocess(path, 0, 0);
     g_test_trap_assert_passed();
+    g_free(path);
 }
 #endif
 
-- 
2.9.0

[Qemu-devel] [PATCH v4 26/29] tests: add /vhost-user/connect-fail test

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Check early connection failure and resume.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 tests/vhost-user-test.c | 38 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
index a0b91ab..6595243 100644
--- a/tests/vhost-user-test.c
+++ b/tests/vhost-user-test.c
@@ -131,6 +131,7 @@ typedef struct TestServer {
     CompatGCond data_cond;
     int log_fd;
     uint64_t rings;
+    bool test_fail;
 } TestServer;
 
 static const char *tmpfs;
@@ -221,6 +222,12 @@ static void chr_read(void *opaque, const uint8_t *buf, int size)
     uint8_t *p = (uint8_t *) &msg;
     int fd;
 
+    if (s->test_fail) {
+        qemu_chr_disconnect(chr);
+        /* now switch to non-failure */
+        s->test_fail = false;
+    }
+
     if (size != VHOST_USER_HDR_SIZE) {
         g_test_message("Wrong message size received %d\n", size);
         return;
@@ -685,6 +692,34 @@ static void test_reconnect(void)
     g_test_trap_assert_passed();
     g_free(path);
 }
+
+static void test_connect_fail_subprocess(void)
+{
+    TestServer *s = test_server_new("reconnect");
+    char *cmd;
+
+    s->test_fail = true;
+    g_thread_new("connect", connect_thread, s);
+    cmd = GET_QEMU_CMDE(s, 2, ",server", "");
+    qtest_start(cmd);
+    g_free(cmd);
+
+    wait_for_fds(s);
+    wait_for_rings_started(s, 2);
+
+    qtest_end();
+    test_server_free(s);
+}
+
+static void test_connect_fail(void)
+{
+    gchar *path = g_strdup_printf("/%s/vhost-user/connect-fail/subprocess",
+                                  qtest_get_arch());
+    g_test_trap_subprocess(path, 0, 0);
+    g_test_trap_assert_passed();
+    g_free(path);
+}
+
 #endif
 
 int main(int argc, char **argv)
@@ -735,6 +770,9 @@ int main(int argc, char **argv)
     qtest_add_func("/vhost-user/reconnect/subprocess",
                    test_reconnect_subprocess);
     qtest_add_func("/vhost-user/reconnect", test_reconnect);
+    qtest_add_func("/vhost-user/connect-fail/subprocess",
+                   test_connect_fail_subprocess);
+    qtest_add_func("/vhost-user/connect-fail", test_connect_fail);
 #endif
 
     ret = g_test_run();
-- 
2.9.0

[Qemu-devel] [PATCH v4 27/29] tests: add a simple /vhost-user/multiqueue test

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

This test just checks that 2 virtio-net queues can be setup over
vhost-user and waits for them to be started.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 tests/Makefile.include  |   2 +-
 tests/vhost-user-test.c | 108 +++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 107 insertions(+), 3 deletions(-)

diff --git a/tests/Makefile.include b/tests/Makefile.include
index 2010b11..3cb57b8 100644
--- a/tests/Makefile.include
+++ b/tests/Makefile.include
@@ -611,7 +611,7 @@ tests/usb-hcd-ehci-test$(EXESUF): tests/usb-hcd-ehci-test.o $(libqos-usb-obj-y)
 tests/usb-hcd-xhci-test$(EXESUF): tests/usb-hcd-xhci-test.o $(libqos-usb-obj-y)
 tests/pc-cpu-test$(EXESUF): tests/pc-cpu-test.o
 tests/postcopy-test$(EXESUF): tests/postcopy-test.o
-tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o qemu-char.o qemu-timer.o $(qtest-obj-y) $(test-io-obj-y)
+tests/vhost-user-test$(EXESUF): tests/vhost-user-test.o qemu-char.o qemu-timer.o $(qtest-obj-y) $(test-io-obj-y) $(libqos-pc-obj-y) $(libqos-virtio-obj-y)
 tests/qemu-iotests/socket_scm_helper$(EXESUF): tests/qemu-iotests/socket_scm_helper.o
 tests/test-qemu-opts$(EXESUF): tests/test-qemu-opts.o $(test-util-obj-y)
 tests/test-write-threshold$(EXESUF): tests/test-write-threshold.o $(test-block-obj-y)
diff --git a/tests/vhost-user-test.c b/tests/vhost-user-test.c
index 6595243..aedbea6 100644
--- a/tests/vhost-user-test.c
+++ b/tests/vhost-user-test.c
@@ -16,6 +16,11 @@
 #include "sysemu/char.h"
 #include "sysemu/sysemu.h"
 
+#include "libqos/pci-pc.h"
+#include "libqos/virtio-pci.h"
+#include "libqos/malloc-pc.h"
+#include "hw/virtio/virtio-net.h"
+
 #include <linux/vhost.h>
 #include <sys/vfs.h>
 #include <qemu/sockets.h>
@@ -46,6 +51,7 @@
 #define VHOST_MEMORY_MAX_NREGIONS    8
 
 #define VHOST_USER_F_PROTOCOL_FEATURES 30
+#define VHOST_USER_PROTOCOL_F_MQ 0
 #define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1
 
 #define VHOST_LOG_PAGE 0x1000
@@ -68,6 +74,7 @@ typedef enum VhostUserRequest {
     VHOST_USER_SET_VRING_ERR = 14,
     VHOST_USER_GET_PROTOCOL_FEATURES = 15,
     VHOST_USER_SET_PROTOCOL_FEATURES = 16,
+    VHOST_USER_GET_QUEUE_NUM = 17,
     VHOST_USER_SET_VRING_ENABLE = 18,
     VHOST_USER_MAX
 } VhostUserRequest;
@@ -132,6 +139,7 @@ typedef struct TestServer {
     int log_fd;
     uint64_t rings;
     bool test_fail;
+    int queues;
 } TestServer;
 
 static const char *tmpfs;
@@ -253,6 +261,9 @@ static void chr_read(void *opaque, const uint8_t *buf, int size)
         msg.size = sizeof(m.payload.u64);
         msg.payload.u64 = 0x1ULL << VHOST_F_LOG_ALL |
             0x1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
+        if (s->queues > 1) {
+            msg.payload.u64 |= 0x1ULL << VIRTIO_NET_F_MQ;
+        }
         p = (uint8_t *) &msg;
         qemu_chr_fe_write_all(chr, p, VHOST_USER_HDR_SIZE + msg.size);
         break;
@@ -267,6 +278,9 @@ static void chr_read(void *opaque, const uint8_t *buf, int size)
         msg.flags |= VHOST_USER_REPLY_MASK;
         msg.size = sizeof(m.payload.u64);
         msg.payload.u64 = 1 << VHOST_USER_PROTOCOL_F_LOG_SHMFD;
+        if (s->queues > 1) {
+            msg.payload.u64 |= 1 << VHOST_USER_PROTOCOL_F_MQ;
+        }
         p = (uint8_t *) &msg;
         qemu_chr_fe_write_all(chr, p, VHOST_USER_HDR_SIZE + msg.size);
         break;
@@ -279,7 +293,7 @@ static void chr_read(void *opaque, const uint8_t *buf, int size)
         p = (uint8_t *) &msg;
         qemu_chr_fe_write_all(chr, p, VHOST_USER_HDR_SIZE + msg.size);
 
-        assert(msg.payload.state.index < 2);
+        assert(msg.payload.state.index < s->queues * 2);
         s->rings &= ~(0x1ULL << msg.payload.state.index);
         break;
 
@@ -319,10 +333,18 @@ static void chr_read(void *opaque, const uint8_t *buf, int size)
         break;
 
     case VHOST_USER_SET_VRING_BASE:
-        assert(msg.payload.state.index < 2);
+        assert(msg.payload.state.index < s->queues * 2);
         s->rings |= 0x1ULL << msg.payload.state.index;
         break;
 
+    case VHOST_USER_GET_QUEUE_NUM:
+        msg.flags |= VHOST_USER_REPLY_MASK;
+        msg.size = sizeof(m.payload.u64);
+        msg.payload.u64 = s->queues;
+        p = (uint8_t *) &msg;
+        qemu_chr_fe_write_all(chr, p, VHOST_USER_HDR_SIZE + msg.size);
+        break;
+
     default:
         break;
     }
@@ -369,6 +391,7 @@ static TestServer *test_server_new(const gchar *name)
     g_cond_init(&server->data_cond);
 
     server->log_fd = -1;
+    server->queues = 1;
 
     return server;
 }
@@ -722,6 +745,86 @@ static void test_connect_fail(void)
 
 #endif
 
+static QVirtioPCIDevice *virtio_net_pci_init(QPCIBus *bus, int slot)
+{
+    QVirtioPCIDevice *dev;
+
+    dev = qvirtio_pci_device_find(bus, VIRTIO_ID_NET);
+    g_assert(dev != NULL);
+    g_assert_cmphex(dev->vdev.device_type, ==, VIRTIO_ID_NET);
+
+    qvirtio_pci_device_enable(dev);
+    qvirtio_reset(&qvirtio_pci, &dev->vdev);
+    qvirtio_set_acknowledge(&qvirtio_pci, &dev->vdev);
+    qvirtio_set_driver(&qvirtio_pci, &dev->vdev);
+
+    return dev;
+}
+
+static void driver_init(const QVirtioBus *bus, QVirtioDevice *dev)
+{
+    uint32_t features;
+
+    features = qvirtio_get_features(bus, dev);
+    features = features & ~(QVIRTIO_F_BAD_FEATURE |
+                            (1u << VIRTIO_RING_F_INDIRECT_DESC) |
+                            (1u << VIRTIO_RING_F_EVENT_IDX));
+    qvirtio_set_features(bus, dev, features);
+
+    qvirtio_set_driver_ok(bus, dev);
+}
+
+#define PCI_SLOT                0x04
+
+static void test_multiqueue(void)
+{
+    const int queues = 2;
+    TestServer *s = test_server_new("mq");
+    QVirtioPCIDevice *dev;
+    QPCIBus *bus;
+    QVirtQueuePCI *vq[queues * 2];
+    QGuestAllocator *alloc;
+    char *cmd;
+    int i;
+
+    s->queues = queues;
+    test_server_listen(s);
+
+    cmd = g_strdup_printf(QEMU_CMD_ACCEL QEMU_CMD_MEM QEMU_CMD_CHR
+                          QEMU_CMD_NETDEV ",queues=%d "
+                          "-device virtio-net-pci,netdev=net0,mq=on,vectors=%d",
+                          512, 512, root, s->chr_name,
+                          s->socket_path, "", s->chr_name,
+                          queues, queues * 2 + 2);
+    qtest_start(cmd);
+    g_free(cmd);
+
+    bus = qpci_init_pc();
+    dev = virtio_net_pci_init(bus, PCI_SLOT);
+
+    alloc = pc_alloc_init();
+    for (i = 0; i < queues * 2; i++) {
+        vq[i] = (QVirtQueuePCI *)qvirtqueue_setup(&qvirtio_pci, &dev->vdev,
+                                              alloc, i);
+    }
+
+    driver_init(&qvirtio_pci, &dev->vdev);
+    wait_for_rings_started(s, queues * 2);
+
+    /* End test */
+    for (i = 0; i < queues * 2; i++) {
+        qvirtqueue_cleanup(&qvirtio_pci, &vq[i]->vq, alloc);
+    }
+    pc_alloc_uninit(alloc);
+    qvirtio_pci_device_disable(dev);
+    g_free(dev->pdev);
+    g_free(dev);
+    qpci_free_pc(bus);
+    qtest_end();
+
+    test_server_free(s);
+}
+
 int main(int argc, char **argv)
 {
     QTestState *s = NULL;
@@ -766,6 +869,7 @@ int main(int argc, char **argv)
 
     qtest_add_data_func("/vhost-user/read-guest-mem", server, read_guest_mem);
     qtest_add_func("/vhost-user/migrate", test_migrate);
+    qtest_add_func("/vhost-user/multiqueue", test_multiqueue);
 #ifdef CONFIG_HAS_GLIB_SUBPROCESS_TESTS
     qtest_add_func("/vhost-user/reconnect/subprocess",
                    test_reconnect_subprocess);
-- 
2.9.0

[Qemu-devel] [PATCH v4 28/29] vhost-user: add error report in vhost_user_write()

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Similar to vhost_user_read() error report, it is useful to have early
error report.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/virtio/vhost-user.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index 819481d..1995fd2 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -176,7 +176,7 @@ static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg,
                             int *fds, int fd_num)
 {
     CharDriverState *chr = dev->opaque;
-    int size = VHOST_USER_HDR_SIZE + msg->size;
+    int ret, size = VHOST_USER_HDR_SIZE + msg->size;
 
     /*
      * For non-vring specific requests, like VHOST_USER_SET_MEM_TABLE,
@@ -188,11 +188,18 @@ static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg,
     }
 
     if (qemu_chr_fe_set_msgfds(chr, fds, fd_num) < 0) {
+        error_report("Failed to set msg fds.");
         return -1;
     }
 
-    return qemu_chr_fe_write_all(chr, (const uint8_t *) msg, size) == size ?
-            0 : -1;
+    ret = qemu_chr_fe_write_all(chr, (const uint8_t *) msg, size);
+    if (ret != size) {
+        error_report("Failed to write msg."
+                     " Wrote %d instead of %d.", ret, size);
+        return -1;
+    }
+
+    return 0;
 }
 
 static int vhost_user_set_log_base(struct vhost_dev *dev, uint64_t base,
-- 
2.9.0

[Qemu-devel] [PATCH v4 29/29] vhost: add vhost_net_set_backend()

[marcandre.lureau]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Not all vhost-user backends support ops->vhost_net_set_backend(), it is
a bit nicer to provide an assert/error than to crash trying to call
it. Furthermore, it improves a bit the code by hiding vhost_ops details.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/net/vhost_net.c        |  9 +++------
 hw/virtio/vhost.c         | 10 ++++++++++
 include/hw/virtio/vhost.h |  4 ++++
 3 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index a8ffcb2..b6c4c5a 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -242,8 +242,7 @@ static int vhost_net_start_one(struct vhost_net *net,
         qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
         file.fd = net->backend;
         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
-            const VhostOps *vhost_ops = net->dev.vhost_ops;
-            r = vhost_ops->vhost_net_set_backend(&net->dev, &file);
+            r = vhost_net_set_backend(&net->dev, &file);
             if (r < 0) {
                 r = -errno;
                 goto fail;
@@ -255,8 +254,7 @@ fail:
     file.fd = -1;
     if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP) {
         while (file.index-- > 0) {
-            const VhostOps *vhost_ops = net->dev.vhost_ops;
-            int r = vhost_ops->vhost_net_set_backend(&net->dev, &file);
+            int r = vhost_net_set_backend(&net->dev, &file);
             assert(r >= 0);
         }
     }
@@ -277,8 +275,7 @@ static void vhost_net_stop_one(struct vhost_net *net,
 
     if (net->nc->info->type == NET_CLIENT_OPTIONS_KIND_TAP) {
         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
-            const VhostOps *vhost_ops = net->dev.vhost_ops;
-            int r = vhost_ops->vhost_net_set_backend(&net->dev, &file);
+            int r = vhost_net_set_backend(&net->dev, &file);
             assert(r >= 0);
         }
     }
diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 3688236..96c57aa 100644
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1313,3 +1313,13 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
     vhost_log_put(hdev, true);
     hdev->started = false;
 }
+
+int vhost_net_set_backend(struct vhost_dev *hdev,
+                          struct vhost_vring_file *file)
+{
+    if (hdev->vhost_ops->vhost_net_set_backend) {
+        return hdev->vhost_ops->vhost_net_set_backend(hdev, file);
+    }
+
+    return -1;
+}
diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index b60d758..4bc8ccd 100644
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -85,4 +85,8 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
 void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
                         uint64_t features);
 bool vhost_has_free_slot(void);
+
+int vhost_net_set_backend(struct vhost_dev *hdev,
+                          struct vhost_vring_file *file);
+
 #endif
-- 
2.9.0

Re: [Qemu-devel] [PATCH v4 00/29] vhost-user reconnect fixes

[Marc-André Lureau]

Hi

On Thu, Jul 7, 2016 at 3:00 AM,  <marcandre.lureau@redhat.com> wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> Hi,
>
> Since 'vhost-user: simple reconnection support' was merged, it is
> possible to disconnect and reconnect a vhost-user backend. However,
> many code paths in qemu may trigger assert() when the backend is
> disconnected.
>
> Some assert() could simply be replaced by error_report() or silently
> fail since they are recoverable cases. Some missing error checks can
> also help prevent later issues. In many cases, the code assumes
> get_vhost_net() will be non-NULL after a succesful connection, so I
> changed it to stay after a disconnect until the new connection comes
> (as suggested by Michael). There are also code paths that are wrong,
> see "don't assume opaque is a fd" patch for an example.
>
> Since there is feature checks on reconnection, qemu should wait for
> the initial connection feature negotiation to complete. The test added
> demonstrates this. Additionally, a regression was found during v2,
> which could have been spotted with a multiqueue test, so add a basic
> one that would have exhibited the issue.
>
> For convenience, the series is also available on:
> https://github.com/elmarco/qemu, branch vhost-user-reconnect

The branch has been rebased fixing conflicts after Jason Wang "busy
polling" got merged.

I also tried to improve the commit log in "vhost: fix calling
vhost_dev_cleanup() after vhost_dev_init()" patch.

thanks

-- 
Marc-André Lureau

Re: [Qemu-devel] [PATCH v4 00/29] vhost-user reconnect fixes

[Michael S. Tsirkin]

On Thu, Jul 07, 2016 at 03:00:24AM +0200, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
> 
> Hi,
> 
> Since 'vhost-user: simple reconnection support' was merged, it is
> possible to disconnect and reconnect a vhost-user backend. However,
> many code paths in qemu may trigger assert() when the backend is
> disconnected.
> 
> Some assert() could simply be replaced by error_report() or silently
> fail since they are recoverable cases. Some missing error checks can
> also help prevent later issues. In many cases, the code assumes
> get_vhost_net() will be non-NULL after a succesful connection, so I
> changed it to stay after a disconnect until the new connection comes
> (as suggested by Michael). There are also code paths that are wrong,
> see "don't assume opaque is a fd" patch for an example.
> 
> Since there is feature checks on reconnection, qemu should wait for
> the initial connection feature negotiation to complete. The test added
> demonstrates this. Additionally, a regression was found during v2,
> which could have been spotted with a multiqueue test, so add a basic
> one that would have exhibited the issue.
> 
> For convenience, the series is also available on:
> https://github.com/elmarco/qemu, branch vhost-user-reconnect

So I'm guessing there will be v5 with a rebase. I sent some minor
comments but overall it's in good shape.
Could you add Cc stable to fixes that make sense there like
(I think) the opaque thing?

Thanks!

> v4:
> - change notify_migration_done() patch to be VHOST_BACKEND_TYPE_USER
>   specific, to avoid having to handle the case where the backend
>   doesn't implement the callback
> - change vhost_dev_cleanup() to assert on empty log, instead of
>   adding a call to vhost_log_put()
> - made "keep vhost_net after a disconnection" more robust, got rid of
>   the acked_features field
> - improve commit log, and some patch reorganization for clarity
> 
> v3:
> - add vhost-user multiqueue test, which would have helped to find the
>   following fix
> - fix waiting on vhost-user connection with multiqueue (found by
>   Yuanhan Liu)
> - merge vhost_user_{read,write}() error checking patches
> - add error reporting to vhost_user_read() (similar to
>   vhost_user_write())
> - add a vhost_net_set_backend() wrapper to help with potential crash
> - some leak fixes
> 
> v2:
> - some patch ordering: minor fix, close(fd) fix,
>   assert/fprintf->error_report, check and return error,
>   vhost_dev_cleanup() fixes, keep vhost_net after a disconnect, wait
>   until connection is ready
> - merge read/write error checks
> - do not rely on link state to check vhost-user init completed
> 
> Marc-André Lureau (29):
>   misc: indentation
>   vhost-user: minor simplification
>   vhost: don't assume opaque is a fd, use backend cleanup
>   vhost: make vhost_log_put() idempotent
>   vhost: assert the log was cleaned up
>   vhost: fix cleanup on not fully initialized device
>   vhost: make vhost_dev_cleanup() idempotent
>   vhost-net: always call vhost_dev_cleanup() on failure
>   vhost: fix calling vhost_dev_cleanup() after vhost_dev_init()
>   vhost: do not assert() on vhost_ops failure
>   vhost: use error_report() instead of fprintf(stderr,...)
>   qemu-char: fix qemu_chr_fe_set_msgfds() crash when disconnected
>   vhost-user: call set_msgfds unconditionally
>   vhost-user: check qemu_chr_fe_set_msgfds() return value
>   vhost-user: check vhost_user_{read,write}() return value
>   vhost-user: keep vhost_net after a disconnection
>   vhost-user: add get_vhost_net() assertions
>   Revert "vhost-net: do not crash if backend is not present"
>   vhost-net: vhost_migration_done is vhost-user specific
>   vhost: add assert() to check runtime behaviour
>   char: add chr_wait_connected callback
>   char: add and use tcp_chr_wait_connected
>   vhost-user: wait until backend init is completed
>   tests: plug some leaks in virtio-net-test
>   tests: fix vhost-user-test leak
>   tests: add /vhost-user/connect-fail test
>   tests: add a simple /vhost-user/multiqueue test
>   vhost-user: add error report in vhost_user_write()
>   vhost: add vhost_net_set_backend()
> 
>  hw/net/vhost_net.c        |  34 ++++-------
>  hw/virtio/vhost-user.c    |  67 ++++++++++++++-------
>  hw/virtio/vhost.c         | 123 +++++++++++++++++++++++---------------
>  include/hw/virtio/vhost.h |   4 ++
>  include/sysemu/char.h     |   8 +++
>  net/tap.c                 |   1 +
>  net/vhost-user.c          |  60 +++++++++++--------
>  qemu-char.c               |  82 ++++++++++++++++++--------
>  tests/Makefile.include    |   2 +-
>  tests/vhost-user-test.c   | 147 +++++++++++++++++++++++++++++++++++++++++++++-
>  tests/virtio-net-test.c   |  12 +++-
>  11 files changed, 396 insertions(+), 144 deletions(-)
> 
> -- 
> 2.9.0