[Qemu-devel] [PATCH 0/4] 9pfs: clean-up for multiple transports

[Qemu-devel] [PATCH 0/4] 9pfs: clean-up for multiple transports

[Stefano Stabellini]

Hi all,

this small patch series provides a few fixes and clean-ups in
preparation for the introduction of a 9pfs Xen transport.


Stefano Stabellini (4):
      9pfs: move pdus to V9fsState
      9pfs: introduce transport specific callbacks
      9pfs: use v9fs_init_qiov_from_pdu instead of v9fs_pack
      9pfs: add a size parameter to init_iov_from_pdu

 hw/9pfs/9p.c               | 71 +++++++++++++++++++++++-----------------------
 hw/9pfs/9p.h               | 19 +++++++++++++
 hw/9pfs/virtio-9p-device.c | 20 +++++++++----
 hw/9pfs/virtio-9p.h        | 10 -------
 4 files changed, 69 insertions(+), 51 deletions(-)

[Qemu-devel] [PATCH 1/4] 9pfs: move pdus to V9fsState

[Stefano Stabellini]

pdus are initialized and used in 9pfs common code. Move the array from
V9fsVirtioState to V9fsState.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/9pfs/9p.c        | 7 +++----
 hw/9pfs/9p.h        | 1 +
 hw/9pfs/virtio-9p.h | 1 -
 3 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index aea7e9d..05e950f 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -3440,7 +3440,6 @@ void pdu_submit(V9fsPDU *pdu)
 /* Returns 0 on success, 1 on failure. */
 int v9fs_device_realize_common(V9fsState *s, Error **errp)
 {
-    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
     int i, len;
     struct stat stat;
     FsDriverEntry *fse;
@@ -3451,9 +3450,9 @@ int v9fs_device_realize_common(V9fsState *s, Error **errp)
     QLIST_INIT(&s->free_list);
     QLIST_INIT(&s->active_list);
     for (i = 0; i < (MAX_REQ - 1); i++) {
-        QLIST_INSERT_HEAD(&s->free_list, &v->pdus[i], next);
-        v->pdus[i].s = s;
-        v->pdus[i].idx = i;
+        QLIST_INSERT_HEAD(&s->free_list, &s->pdus[i], next);
+        s->pdus[i].s = s;
+        s->pdus[i].idx = i;
     }
 
     v9fs_path_init(&path);
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index 3976b7f..07cee01 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -229,6 +229,7 @@ typedef struct V9fsState
     char *tag;
     enum p9_proto_version proto_version;
     int32_t msize;
+    V9fsPDU pdus[MAX_REQ];
     /*
      * lock ensuring atomic path update
      * on rename.
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index 25c47c7..52c4b9d 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -10,7 +10,6 @@ typedef struct V9fsVirtioState
     VirtIODevice parent_obj;
     VirtQueue *vq;
     size_t config_size;
-    V9fsPDU pdus[MAX_REQ];
     VirtQueueElement *elems[MAX_REQ];
     V9fsState state;
 } V9fsVirtioState;
-- 
1.9.1

[Qemu-devel] [PATCH 2/4] 9pfs: introduce transport specific callbacks

[Stefano Stabellini]

Don't call virtio functions from 9pfs generic code, use generic function
callbacks instead.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/9pfs/9p.c               |  8 ++++----
 hw/9pfs/9p.h               | 18 ++++++++++++++++++
 hw/9pfs/virtio-9p-device.c | 18 ++++++++++++++----
 hw/9pfs/virtio-9p.h        |  9 ---------
 4 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 05e950f..5a20a13 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -47,7 +47,7 @@ ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
     va_list ap;
 
     va_start(ap, fmt);
-    ret = virtio_pdu_vmarshal(pdu, offset, fmt, ap);
+    ret = pdu->s->transport->pdu_vmarshal(pdu, offset, fmt, ap);
     va_end(ap);
 
     return ret;
@@ -59,7 +59,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
     va_list ap;
 
     va_start(ap, fmt);
-    ret = virtio_pdu_vunmarshal(pdu, offset, fmt, ap);
+    ret = pdu->s->transport->pdu_vunmarshal(pdu, offset, fmt, ap);
     va_end(ap);
 
     return ret;
@@ -67,7 +67,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
 
 static void pdu_push_and_notify(V9fsPDU *pdu)
 {
-    virtio_9p_push_and_notify(pdu);
+    pdu->s->transport->push_and_notify(pdu);
 }
 
 static int omode_to_uflags(int8_t mode)
@@ -1751,7 +1751,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
     struct iovec *iov;
     unsigned int niov;
 
-    virtio_init_iov_from_pdu(pdu, &iov, &niov, is_write);
+    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
 
     qemu_iovec_init_external(&elem, iov, niov);
     qemu_iovec_init(qiov, niov);
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index 07cee01..ab398d0 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -230,6 +230,7 @@ typedef struct V9fsState
     enum p9_proto_version proto_version;
     int32_t msize;
     V9fsPDU pdus[MAX_REQ];
+    struct V9fsTransport *transport;
     /*
      * lock ensuring atomic path update
      * on rename.
@@ -343,4 +344,21 @@ void pdu_free(V9fsPDU *pdu);
 void pdu_submit(V9fsPDU *pdu);
 void v9fs_reset(V9fsState *s);
 
+struct V9fsTransport {
+    ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
+    ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
+    void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
+                              unsigned int *pniov, bool is_write);
+    void        (*push_and_notify)(V9fsPDU *pdu);
+};
+
+static inline int v9fs_register_transport(V9fsState *s, struct V9fsTransport *t)
+{
+    if (s->transport) {
+        return -EINVAL;
+    }
+    s->transport = t;
+    return 0;
+}
+
 #endif
diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index 1782e4a..e1a37a4 100644
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -20,7 +20,9 @@
 #include "hw/virtio/virtio-access.h"
 #include "qemu/iov.h"
 
-void virtio_9p_push_and_notify(V9fsPDU *pdu)
+static struct V9fsTransport virtio_9p_transport;
+
+static void virtio_9p_push_and_notify(V9fsPDU *pdu)
 {
     V9fsState *s = pdu->s;
     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
@@ -126,6 +128,7 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
     v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
     virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
     v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
+    v9fs_register_transport(s, &virtio_9p_transport);
 
 out:
     return;
@@ -148,7 +151,7 @@ static void virtio_9p_reset(VirtIODevice *vdev)
     v9fs_reset(&v->state);
 }
 
-ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
+static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
                             const char *fmt, va_list ap)
 {
     V9fsState *s = pdu->s;
@@ -158,7 +161,7 @@ ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
     return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
 }
 
-ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
+static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
                               const char *fmt, va_list ap)
 {
     V9fsState *s = pdu->s;
@@ -168,7 +171,7 @@ ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
     return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
 }
 
-void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
+static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
                               unsigned int *pniov, bool is_write)
 {
     V9fsState *s = pdu->s;
@@ -184,6 +187,13 @@ void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
     }
 }
 
+static struct V9fsTransport virtio_9p_transport = {
+    .pdu_vmarshal = virtio_pdu_vmarshal,
+    .pdu_vunmarshal = virtio_pdu_vunmarshal,
+    .init_iov_from_pdu = virtio_init_iov_from_pdu,
+    .push_and_notify = virtio_9p_push_and_notify,
+};
+
 /* virtio-9p device */
 
 static const VMStateDescription vmstate_virtio_9p = {
diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
index 52c4b9d..e763da2c 100644
--- a/hw/9pfs/virtio-9p.h
+++ b/hw/9pfs/virtio-9p.h
@@ -14,15 +14,6 @@ typedef struct V9fsVirtioState
     V9fsState state;
 } V9fsVirtioState;
 
-void virtio_9p_push_and_notify(V9fsPDU *pdu);
-
-ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
-                            const char *fmt, va_list ap);
-ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
-                              const char *fmt, va_list ap);
-void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
-                              unsigned int *pniov, bool is_write);
-
 #define TYPE_VIRTIO_9P "virtio-9p-device"
 #define VIRTIO_9P(obj) \
         OBJECT_CHECK(V9fsVirtioState, (obj), TYPE_VIRTIO_9P)
-- 
1.9.1

[Qemu-devel] [PATCH 3/4] 9pfs: use v9fs_init_qiov_from_pdu instead of v9fs_pack

[Stefano Stabellini]

v9fs_xattr_read should not access VirtQueueElement elems directly.
Move v9fs_init_qiov_from_pdu up in the file and call
v9fs_init_qiov_from_pdu instead of v9fs_pack.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/9pfs/9p.c | 58 +++++++++++++++++++++++++++++-----------------------------
 1 file changed, 29 insertions(+), 29 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index 5a20a13..b6ec042 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1633,14 +1633,39 @@ out_nofid:
     pdu_complete(pdu, err);
 }
 
+/*
+ * Create a QEMUIOVector for a sub-region of PDU iovecs
+ *
+ * @qiov:       uninitialized QEMUIOVector
+ * @skip:       number of bytes to skip from beginning of PDU
+ * @size:       number of bytes to include
+ * @is_write:   true - write, false - read
+ *
+ * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
+ * with qemu_iovec_destroy().
+ */
+static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
+                                    size_t skip, size_t size,
+                                    bool is_write)
+{
+    QEMUIOVector elem;
+    struct iovec *iov;
+    unsigned int niov;
+
+    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
+
+    qemu_iovec_init_external(&elem, iov, niov);
+    qemu_iovec_init(qiov, niov);
+    qemu_iovec_concat(qiov, &elem, skip, size);
+}
+
 static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
                            uint64_t off, uint32_t max_count)
 {
     ssize_t err;
     size_t offset = 7;
     uint64_t read_count;
-    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
-    VirtQueueElement *elem = v->elems[pdu->idx];
+    QEMUIOVector qiov_full;
 
     if (fidp->fs.xattr.len < off) {
         read_count = 0;
@@ -1656,7 +1681,8 @@ static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
     }
     offset += err;
 
-    err = v9fs_pack(elem->in_sg, elem->in_num, offset,
+    v9fs_init_qiov_from_pdu(&qiov_full, pdu, 0, read_count, false);
+    err = v9fs_pack(qiov_full.iov, qiov_full.niov, offset,
                     ((char *)fidp->fs.xattr.value) + off,
                     read_count);
     if (err < 0) {
@@ -1732,32 +1758,6 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
     return count;
 }
 
-/*
- * Create a QEMUIOVector for a sub-region of PDU iovecs
- *
- * @qiov:       uninitialized QEMUIOVector
- * @skip:       number of bytes to skip from beginning of PDU
- * @size:       number of bytes to include
- * @is_write:   true - write, false - read
- *
- * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
- * with qemu_iovec_destroy().
- */
-static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
-                                    size_t skip, size_t size,
-                                    bool is_write)
-{
-    QEMUIOVector elem;
-    struct iovec *iov;
-    unsigned int niov;
-
-    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
-
-    qemu_iovec_init_external(&elem, iov, niov);
-    qemu_iovec_init(qiov, niov);
-    qemu_iovec_concat(qiov, &elem, skip, size);
-}
-
 static void coroutine_fn v9fs_read(void *opaque)
 {
     int32_t fid;
-- 
1.9.1

[Qemu-devel] [PATCH 4/4] 9pfs: add a size parameter to init_iov_from_pdu

[Stefano Stabellini]

Not all 9pfs transports share memory between request and response. For
those who don't, it is necessary to know how much memory is required in
the response.

Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
---
 hw/9pfs/9p.c               | 2 +-
 hw/9pfs/9p.h               | 2 +-
 hw/9pfs/virtio-9p-device.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
index b6ec042..b82212b 100644
--- a/hw/9pfs/9p.c
+++ b/hw/9pfs/9p.c
@@ -1652,7 +1652,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
     struct iovec *iov;
     unsigned int niov;
 
-    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
+    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write, skip + size);
 
     qemu_iovec_init_external(&elem, iov, niov);
     qemu_iovec_init(qiov, niov);
diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
index ab398d0..c830188 100644
--- a/hw/9pfs/9p.h
+++ b/hw/9pfs/9p.h
@@ -348,7 +348,7 @@ struct V9fsTransport {
     ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
     ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
     void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
-                              unsigned int *pniov, bool is_write);
+                              unsigned int *pniov, bool is_write, size_t size);
     void        (*push_and_notify)(V9fsPDU *pdu);
 };
 
diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
index e1a37a4..e2b27e8 100644
--- a/hw/9pfs/virtio-9p-device.c
+++ b/hw/9pfs/virtio-9p-device.c
@@ -172,7 +172,7 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
 }
 
 static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
-                              unsigned int *pniov, bool is_write)
+                              unsigned int *pniov, bool is_write, size_t size)
 {
     V9fsState *s = pdu->s;
     V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
-- 
1.9.1

Re: [Qemu-devel] [PATCH 1/4] 9pfs: move pdus to V9fsState

[Greg Kurz]

On Mon, 21 Nov 2016 13:39:29 -0800
Stefano Stabellini <sstabellini@kernel.org> wrote:

> pdus are initialized and used in 9pfs common code. Move the array from
> V9fsVirtioState to V9fsState.
> 
> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> ---

Reviewed-by: Greg Kurz <groug@kaod.org>

>  hw/9pfs/9p.c        | 7 +++----
>  hw/9pfs/9p.h        | 1 +
>  hw/9pfs/virtio-9p.h | 1 -
>  3 files changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index aea7e9d..05e950f 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -3440,7 +3440,6 @@ void pdu_submit(V9fsPDU *pdu)
>  /* Returns 0 on success, 1 on failure. */
>  int v9fs_device_realize_common(V9fsState *s, Error **errp)
>  {
> -    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
>      int i, len;
>      struct stat stat;
>      FsDriverEntry *fse;
> @@ -3451,9 +3450,9 @@ int v9fs_device_realize_common(V9fsState *s, Error **errp)
>      QLIST_INIT(&s->free_list);
>      QLIST_INIT(&s->active_list);
>      for (i = 0; i < (MAX_REQ - 1); i++) {
> -        QLIST_INSERT_HEAD(&s->free_list, &v->pdus[i], next);
> -        v->pdus[i].s = s;
> -        v->pdus[i].idx = i;
> +        QLIST_INSERT_HEAD(&s->free_list, &s->pdus[i], next);
> +        s->pdus[i].s = s;
> +        s->pdus[i].idx = i;
>      }
>  
>      v9fs_path_init(&path);
> diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> index 3976b7f..07cee01 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -229,6 +229,7 @@ typedef struct V9fsState
>      char *tag;
>      enum p9_proto_version proto_version;
>      int32_t msize;
> +    V9fsPDU pdus[MAX_REQ];
>      /*
>       * lock ensuring atomic path update
>       * on rename.
> diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> index 25c47c7..52c4b9d 100644
> --- a/hw/9pfs/virtio-9p.h
> +++ b/hw/9pfs/virtio-9p.h
> @@ -10,7 +10,6 @@ typedef struct V9fsVirtioState
>      VirtIODevice parent_obj;
>      VirtQueue *vq;
>      size_t config_size;
> -    V9fsPDU pdus[MAX_REQ];
>      VirtQueueElement *elems[MAX_REQ];
>      V9fsState state;
>  } V9fsVirtioState;

Re: [Qemu-devel] [PATCH 2/4] 9pfs: introduce transport specific callbacks

[Greg Kurz]

On Mon, 21 Nov 2016 13:39:30 -0800
Stefano Stabellini <sstabellini@kernel.org> wrote:

> Don't call virtio functions from 9pfs generic code, use generic function
> callbacks instead.
> 
> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> ---

Just a couple of indentation and line over 80 characters nits. I'll fix them
before pushing to 9p-next.

Reviewed-by: Greg Kurz <groug@kaod.org>

>  hw/9pfs/9p.c               |  8 ++++----
>  hw/9pfs/9p.h               | 18 ++++++++++++++++++
>  hw/9pfs/virtio-9p-device.c | 18 ++++++++++++++----
>  hw/9pfs/virtio-9p.h        |  9 ---------
>  4 files changed, 36 insertions(+), 17 deletions(-)
> 
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 05e950f..5a20a13 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -47,7 +47,7 @@ ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>      va_list ap;
>  
>      va_start(ap, fmt);
> -    ret = virtio_pdu_vmarshal(pdu, offset, fmt, ap);
> +    ret = pdu->s->transport->pdu_vmarshal(pdu, offset, fmt, ap);
>      va_end(ap);
>  
>      return ret;
> @@ -59,7 +59,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>      va_list ap;
>  
>      va_start(ap, fmt);
> -    ret = virtio_pdu_vunmarshal(pdu, offset, fmt, ap);
> +    ret = pdu->s->transport->pdu_vunmarshal(pdu, offset, fmt, ap);
>      va_end(ap);
>  
>      return ret;
> @@ -67,7 +67,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
>  
>  static void pdu_push_and_notify(V9fsPDU *pdu)
>  {
> -    virtio_9p_push_and_notify(pdu);
> +    pdu->s->transport->push_and_notify(pdu);
>  }
>  
>  static int omode_to_uflags(int8_t mode)
> @@ -1751,7 +1751,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
>      struct iovec *iov;
>      unsigned int niov;
>  
> -    virtio_init_iov_from_pdu(pdu, &iov, &niov, is_write);
> +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
>  
>      qemu_iovec_init_external(&elem, iov, niov);
>      qemu_iovec_init(qiov, niov);
> diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> index 07cee01..ab398d0 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -230,6 +230,7 @@ typedef struct V9fsState
>      enum p9_proto_version proto_version;
>      int32_t msize;
>      V9fsPDU pdus[MAX_REQ];
> +    struct V9fsTransport *transport;
>      /*
>       * lock ensuring atomic path update
>       * on rename.
> @@ -343,4 +344,21 @@ void pdu_free(V9fsPDU *pdu);
>  void pdu_submit(V9fsPDU *pdu);
>  void v9fs_reset(V9fsState *s);
>  
> +struct V9fsTransport {
> +    ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);

over 80 characters

> +    ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);

ditto

> +    void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> +                              unsigned int *pniov, bool is_write);

indent

> +    void        (*push_and_notify)(V9fsPDU *pdu);
> +};
> +
> +static inline int v9fs_register_transport(V9fsState *s, struct V9fsTransport *t)
> +{
> +    if (s->transport) {
> +        return -EINVAL;
> +    }
> +    s->transport = t;
> +    return 0;
> +}
> +
>  #endif
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index 1782e4a..e1a37a4 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -20,7 +20,9 @@
>  #include "hw/virtio/virtio-access.h"
>  #include "qemu/iov.h"
>  
> -void virtio_9p_push_and_notify(V9fsPDU *pdu)
> +static struct V9fsTransport virtio_9p_transport;
> +
> +static void virtio_9p_push_and_notify(V9fsPDU *pdu)
>  {
>      V9fsState *s = pdu->s;
>      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> @@ -126,6 +128,7 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
>      v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
>      virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
>      v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
> +    v9fs_register_transport(s, &virtio_9p_transport);
>  
>  out:
>      return;
> @@ -148,7 +151,7 @@ static void virtio_9p_reset(VirtIODevice *vdev)
>      v9fs_reset(&v->state);
>  }
>  
> -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> +static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
>                              const char *fmt, va_list ap)

indent

>  {
>      V9fsState *s = pdu->s;
> @@ -158,7 +161,7 @@ ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
>      return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
>  }
>  
> -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> +static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
>                                const char *fmt, va_list ap)

indent

>  {
>      V9fsState *s = pdu->s;
> @@ -168,7 +171,7 @@ ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
>      return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
>  }
>  
> -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> +static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
>                                unsigned int *pniov, bool is_write)

indent

>  {
>      V9fsState *s = pdu->s;
> @@ -184,6 +187,13 @@ void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
>      }
>  }
>  
> +static struct V9fsTransport virtio_9p_transport = {
> +    .pdu_vmarshal = virtio_pdu_vmarshal,
> +    .pdu_vunmarshal = virtio_pdu_vunmarshal,
> +    .init_iov_from_pdu = virtio_init_iov_from_pdu,
> +    .push_and_notify = virtio_9p_push_and_notify,
> +};
> +
>  /* virtio-9p device */
>  
>  static const VMStateDescription vmstate_virtio_9p = {
> diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> index 52c4b9d..e763da2c 100644
> --- a/hw/9pfs/virtio-9p.h
> +++ b/hw/9pfs/virtio-9p.h
> @@ -14,15 +14,6 @@ typedef struct V9fsVirtioState
>      V9fsState state;
>  } V9fsVirtioState;
>  
> -void virtio_9p_push_and_notify(V9fsPDU *pdu);
> -
> -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> -                            const char *fmt, va_list ap);
> -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> -                              const char *fmt, va_list ap);
> -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> -                              unsigned int *pniov, bool is_write);
> -
>  #define TYPE_VIRTIO_9P "virtio-9p-device"
>  #define VIRTIO_9P(obj) \
>          OBJECT_CHECK(V9fsVirtioState, (obj), TYPE_VIRTIO_9P)

Re: [Qemu-devel] [PATCH 2/4] 9pfs: introduce transport specific callbacks

[Greg Kurz]

On Thu, 24 Nov 2016 09:31:52 +0100
Greg Kurz <groug@kaod.org> wrote:

> On Mon, 21 Nov 2016 13:39:30 -0800
> Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> > Don't call virtio functions from 9pfs generic code, use generic function
> > callbacks instead.
> > 
> > Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> > ---  
> 
> Just a couple of indentation and line over 80 characters nits. I'll fix them
> before pushing to 9p-next.
> 
> Reviewed-by: Greg Kurz <groug@kaod.org>
> 

Hmm... second thought...

> >  hw/9pfs/9p.c               |  8 ++++----
> >  hw/9pfs/9p.h               | 18 ++++++++++++++++++
> >  hw/9pfs/virtio-9p-device.c | 18 ++++++++++++++----
> >  hw/9pfs/virtio-9p.h        |  9 ---------
> >  4 files changed, 36 insertions(+), 17 deletions(-)
> > 
> > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> > index 05e950f..5a20a13 100644
> > --- a/hw/9pfs/9p.c
> > +++ b/hw/9pfs/9p.c
> > @@ -47,7 +47,7 @@ ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
> >      va_list ap;
> >  
> >      va_start(ap, fmt);
> > -    ret = virtio_pdu_vmarshal(pdu, offset, fmt, ap);
> > +    ret = pdu->s->transport->pdu_vmarshal(pdu, offset, fmt, ap);
> >      va_end(ap);
> >  
> >      return ret;
> > @@ -59,7 +59,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
> >      va_list ap;
> >  
> >      va_start(ap, fmt);
> > -    ret = virtio_pdu_vunmarshal(pdu, offset, fmt, ap);
> > +    ret = pdu->s->transport->pdu_vunmarshal(pdu, offset, fmt, ap);
> >      va_end(ap);
> >  
> >      return ret;
> > @@ -67,7 +67,7 @@ ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...)
> >  
> >  static void pdu_push_and_notify(V9fsPDU *pdu)
> >  {
> > -    virtio_9p_push_and_notify(pdu);
> > +    pdu->s->transport->push_and_notify(pdu);
> >  }
> >  
> >  static int omode_to_uflags(int8_t mode)
> > @@ -1751,7 +1751,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
> >      struct iovec *iov;
> >      unsigned int niov;
> >  
> > -    virtio_init_iov_from_pdu(pdu, &iov, &niov, is_write);
> > +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> >  
> >      qemu_iovec_init_external(&elem, iov, niov);
> >      qemu_iovec_init(qiov, niov);
> > diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> > index 07cee01..ab398d0 100644
> > --- a/hw/9pfs/9p.h
> > +++ b/hw/9pfs/9p.h
> > @@ -230,6 +230,7 @@ typedef struct V9fsState
> >      enum p9_proto_version proto_version;
> >      int32_t msize;
> >      V9fsPDU pdus[MAX_REQ];
> > +    struct V9fsTransport *transport;
> >      /*
> >       * lock ensuring atomic path update
> >       * on rename.
> > @@ -343,4 +344,21 @@ void pdu_free(V9fsPDU *pdu);
> >  void pdu_submit(V9fsPDU *pdu);
> >  void v9fs_reset(V9fsState *s);
> >  
> > +struct V9fsTransport {
> > +    ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);  
> 
> over 80 characters
> 
> > +    ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);  
> 
> ditto
> 
> > +    void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> > +                              unsigned int *pniov, bool is_write);  
> 
> indent
> 
> > +    void        (*push_and_notify)(V9fsPDU *pdu);
> > +};
> > +
> > +static inline int v9fs_register_transport(V9fsState *s, struct V9fsTransport *t)
> > +{
> > +    if (s->transport) {
> > +        return -EINVAL;
> > +    }
> > +    s->transport = t;
> > +    return 0;
> > +}
> > +
> >  #endif
> > diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> > index 1782e4a..e1a37a4 100644
> > --- a/hw/9pfs/virtio-9p-device.c
> > +++ b/hw/9pfs/virtio-9p-device.c
> > @@ -20,7 +20,9 @@
> >  #include "hw/virtio/virtio-access.h"
> >  #include "qemu/iov.h"
> >  
> > -void virtio_9p_push_and_notify(V9fsPDU *pdu)
> > +static struct V9fsTransport virtio_9p_transport;

... shouldn't this be const ?

> > +
> > +static void virtio_9p_push_and_notify(V9fsPDU *pdu)
> >  {
> >      V9fsState *s = pdu->s;
> >      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> > @@ -126,6 +128,7 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
> >      v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
> >      virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
> >      v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
> > +    v9fs_register_transport(s, &virtio_9p_transport);
> >  
> >  out:
> >      return;
> > @@ -148,7 +151,7 @@ static void virtio_9p_reset(VirtIODevice *vdev)
> >      v9fs_reset(&v->state);
> >  }
> >  
> > -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> > +static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> >                              const char *fmt, va_list ap)  
> 
> indent
> 
> >  {
> >      V9fsState *s = pdu->s;
> > @@ -158,7 +161,7 @@ ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> >      return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
> >  }
> >  
> > -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> > +static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> >                                const char *fmt, va_list ap)  
> 
> indent
> 
> >  {
> >      V9fsState *s = pdu->s;
> > @@ -168,7 +171,7 @@ ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> >      return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
> >  }
> >  
> > -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > +static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> >                                unsigned int *pniov, bool is_write)  
> 
> indent
> 
> >  {
> >      V9fsState *s = pdu->s;
> > @@ -184,6 +187,13 @@ void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> >      }
> >  }
> >  
> > +static struct V9fsTransport virtio_9p_transport = {
> > +    .pdu_vmarshal = virtio_pdu_vmarshal,
> > +    .pdu_vunmarshal = virtio_pdu_vunmarshal,
> > +    .init_iov_from_pdu = virtio_init_iov_from_pdu,
> > +    .push_and_notify = virtio_9p_push_and_notify,
> > +};
> > +
> >  /* virtio-9p device */
> >  
> >  static const VMStateDescription vmstate_virtio_9p = {
> > diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> > index 52c4b9d..e763da2c 100644
> > --- a/hw/9pfs/virtio-9p.h
> > +++ b/hw/9pfs/virtio-9p.h
> > @@ -14,15 +14,6 @@ typedef struct V9fsVirtioState
> >      V9fsState state;
> >  } V9fsVirtioState;
> >  
> > -void virtio_9p_push_and_notify(V9fsPDU *pdu);
> > -
> > -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> > -                            const char *fmt, va_list ap);
> > -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> > -                              const char *fmt, va_list ap);
> > -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > -                              unsigned int *pniov, bool is_write);
> > -
> >  #define TYPE_VIRTIO_9P "virtio-9p-device"
> >  #define VIRTIO_9P(obj) \
> >          OBJECT_CHECK(V9fsVirtioState, (obj), TYPE_VIRTIO_9P)  
> 
> 

Re: [Qemu-devel] [PATCH 2/4] 9pfs: introduce transport specific callbacks

[Greg Kurz]

On Thu, 24 Nov 2016 15:23:10 +0100
Greg Kurz <groug@kaod.org> wrote:

> On Thu, 24 Nov 2016 09:31:52 +0100
> Greg Kurz <groug@kaod.org> wrote:
> 
> > On Mon, 21 Nov 2016 13:39:30 -0800
> > Stefano Stabellini <sstabellini@kernel.org> wrote:
> >   
> > > Don't call virtio functions from 9pfs generic code, use generic function
> > > callbacks instead.
> > > 
> > > Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> > > ---    
> > 
> > Just a couple of indentation and line over 80 characters nits. I'll fix them
> > before pushing to 9p-next.
> > 
> > Reviewed-by: Greg Kurz <groug@kaod.org>
> >   
> 
> Hmm... second thought...
> 

[...]

> > > +
> > > +static inline int v9fs_register_transport(V9fsState *s, struct V9fsTransport *t)
> > > +{
> > > +    if (s->transport) {
> > > +        return -EINVAL;
> > > +    }

Calling v9fs_register_transport() several times for the same V9fsState looks
more like a bug than an error... also, is it possible to have several 9pfs
shares with different transports ?

> > > +    s->transport = t;
> > > +    return 0;
> > > +}
> > > +
> > >  #endif
> > > diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> > > index 1782e4a..e1a37a4 100644
> > > --- a/hw/9pfs/virtio-9p-device.c
> > > +++ b/hw/9pfs/virtio-9p-device.c
> > > @@ -20,7 +20,9 @@
> > >  #include "hw/virtio/virtio-access.h"
> > >  #include "qemu/iov.h"
> > >  
> > > -void virtio_9p_push_and_notify(V9fsPDU *pdu)
> > > +static struct V9fsTransport virtio_9p_transport;  
> 
> ... shouldn't this be const ?
> 
> > > +
> > > +static void virtio_9p_push_and_notify(V9fsPDU *pdu)
> > >  {
> > >      V9fsState *s = pdu->s;
> > >      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> > > @@ -126,6 +128,7 @@ static void virtio_9p_device_realize(DeviceState *dev, Error **errp)
> > >      v->config_size = sizeof(struct virtio_9p_config) + strlen(s->fsconf.tag);
> > >      virtio_init(vdev, "virtio-9p", VIRTIO_ID_9P, v->config_size);
> > >      v->vq = virtio_add_queue(vdev, MAX_REQ, handle_9p_output);
> > > +    v9fs_register_transport(s, &virtio_9p_transport);
> > >  
> > >  out:
> > >      return;
> > > @@ -148,7 +151,7 @@ static void virtio_9p_reset(VirtIODevice *vdev)
> > >      v9fs_reset(&v->state);
> > >  }
> > >  
> > > -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> > > +static ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> > >                              const char *fmt, va_list ap)    
> > 
> > indent
> >   
> > >  {
> > >      V9fsState *s = pdu->s;
> > > @@ -158,7 +161,7 @@ ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> > >      return v9fs_iov_vmarshal(elem->in_sg, elem->in_num, offset, 1, fmt, ap);
> > >  }
> > >  
> > > -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> > > +static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> > >                                const char *fmt, va_list ap)    
> > 
> > indent
> >   
> > >  {
> > >      V9fsState *s = pdu->s;
> > > @@ -168,7 +171,7 @@ ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> > >      return v9fs_iov_vunmarshal(elem->out_sg, elem->out_num, offset, 1, fmt, ap);
> > >  }
> > >  
> > > -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > > +static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > >                                unsigned int *pniov, bool is_write)    
> > 
> > indent
> >   
> > >  {
> > >      V9fsState *s = pdu->s;
> > > @@ -184,6 +187,13 @@ void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > >      }
> > >  }
> > >  
> > > +static struct V9fsTransport virtio_9p_transport = {
> > > +    .pdu_vmarshal = virtio_pdu_vmarshal,
> > > +    .pdu_vunmarshal = virtio_pdu_vunmarshal,
> > > +    .init_iov_from_pdu = virtio_init_iov_from_pdu,
> > > +    .push_and_notify = virtio_9p_push_and_notify,
> > > +};
> > > +
> > >  /* virtio-9p device */
> > >  
> > >  static const VMStateDescription vmstate_virtio_9p = {
> > > diff --git a/hw/9pfs/virtio-9p.h b/hw/9pfs/virtio-9p.h
> > > index 52c4b9d..e763da2c 100644
> > > --- a/hw/9pfs/virtio-9p.h
> > > +++ b/hw/9pfs/virtio-9p.h
> > > @@ -14,15 +14,6 @@ typedef struct V9fsVirtioState
> > >      V9fsState state;
> > >  } V9fsVirtioState;
> > >  
> > > -void virtio_9p_push_and_notify(V9fsPDU *pdu);
> > > -
> > > -ssize_t virtio_pdu_vmarshal(V9fsPDU *pdu, size_t offset,
> > > -                            const char *fmt, va_list ap);
> > > -ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> > > -                              const char *fmt, va_list ap);
> > > -void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > > -                              unsigned int *pniov, bool is_write);
> > > -
> > >  #define TYPE_VIRTIO_9P "virtio-9p-device"
> > >  #define VIRTIO_9P(obj) \
> > >          OBJECT_CHECK(V9fsVirtioState, (obj), TYPE_VIRTIO_9P)    
> > 
> >   
> 
> 

Re: [Qemu-devel] [PATCH 3/4] 9pfs: use v9fs_init_qiov_from_pdu instead of v9fs_pack

[Greg Kurz]

On Mon, 21 Nov 2016 13:39:31 -0800
Stefano Stabellini <sstabellini@kernel.org> wrote:

> v9fs_xattr_read should not access VirtQueueElement elems directly.
> Move v9fs_init_qiov_from_pdu up in the file and call
> v9fs_init_qiov_from_pdu instead of v9fs_pack.
> 

instead of ? I see v9fs_init_qiov_from_pdu() gets called before calling v9fs_pack().
Also, I don't see the corresponding call to qemu_iovec_destroy() to free the
allocated iovec.

> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> ---
>  hw/9pfs/9p.c | 58 +++++++++++++++++++++++++++++-----------------------------
>  1 file changed, 29 insertions(+), 29 deletions(-)
> 
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index 5a20a13..b6ec042 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -1633,14 +1633,39 @@ out_nofid:
>      pdu_complete(pdu, err);
>  }
>  
> +/*
> + * Create a QEMUIOVector for a sub-region of PDU iovecs
> + *
> + * @qiov:       uninitialized QEMUIOVector
> + * @skip:       number of bytes to skip from beginning of PDU
> + * @size:       number of bytes to include
> + * @is_write:   true - write, false - read
> + *
> + * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
> + * with qemu_iovec_destroy().
> + */
> +static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
> +                                    size_t skip, size_t size,
> +                                    bool is_write)
> +{
> +    QEMUIOVector elem;
> +    struct iovec *iov;
> +    unsigned int niov;
> +
> +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> +
> +    qemu_iovec_init_external(&elem, iov, niov);
> +    qemu_iovec_init(qiov, niov);
> +    qemu_iovec_concat(qiov, &elem, skip, size);
> +}
> +
>  static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
>                             uint64_t off, uint32_t max_count)
>  {
>      ssize_t err;
>      size_t offset = 7;
>      uint64_t read_count;
> -    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> -    VirtQueueElement *elem = v->elems[pdu->idx];
> +    QEMUIOVector qiov_full;
>  
>      if (fidp->fs.xattr.len < off) {
>          read_count = 0;
> @@ -1656,7 +1681,8 @@ static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
>      }
>      offset += err;
>  
> -    err = v9fs_pack(elem->in_sg, elem->in_num, offset,
> +    v9fs_init_qiov_from_pdu(&qiov_full, pdu, 0, read_count, false);
> +    err = v9fs_pack(qiov_full.iov, qiov_full.niov, offset,
>                      ((char *)fidp->fs.xattr.value) + off,
>                      read_count);
>      if (err < 0) {
> @@ -1732,32 +1758,6 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
>      return count;
>  }
>  
> -/*
> - * Create a QEMUIOVector for a sub-region of PDU iovecs
> - *
> - * @qiov:       uninitialized QEMUIOVector
> - * @skip:       number of bytes to skip from beginning of PDU
> - * @size:       number of bytes to include
> - * @is_write:   true - write, false - read
> - *
> - * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
> - * with qemu_iovec_destroy().
> - */
> -static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
> -                                    size_t skip, size_t size,
> -                                    bool is_write)
> -{
> -    QEMUIOVector elem;
> -    struct iovec *iov;
> -    unsigned int niov;
> -
> -    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> -
> -    qemu_iovec_init_external(&elem, iov, niov);
> -    qemu_iovec_init(qiov, niov);
> -    qemu_iovec_concat(qiov, &elem, skip, size);
> -}
> -
>  static void coroutine_fn v9fs_read(void *opaque)
>  {
>      int32_t fid;

Re: [Qemu-devel] [PATCH 4/4] 9pfs: add a size parameter to init_iov_from_pdu

[Greg Kurz]

On Mon, 21 Nov 2016 13:39:32 -0800
Stefano Stabellini <sstabellini@kernel.org> wrote:

> Not all 9pfs transports share memory between request and response. For
> those who don't, it is necessary to know how much memory is required in
> the response.
> 
> Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> ---

IIUC the transport used in Xen requires you pass the size when sending a
P9_RREAD message back to the guest, i.e. only in the case when is_write is
false, correct ?

If so, for better clarity, what about having two distinct init_in_iov_from_pdu
and init_out_iov_from_pdu ops, with an explicit comment in the virtio-9p
implementation of init_in_iov_from_pdu so that someone isn't tempted to drop
the apparently unused size argument ? Would this be ok for you on the Xen
side ?

Cheers.

--
Greg

>  hw/9pfs/9p.c               | 2 +-
>  hw/9pfs/9p.h               | 2 +-
>  hw/9pfs/virtio-9p-device.c | 2 +-
>  3 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> index b6ec042..b82212b 100644
> --- a/hw/9pfs/9p.c
> +++ b/hw/9pfs/9p.c
> @@ -1652,7 +1652,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
>      struct iovec *iov;
>      unsigned int niov;
>  
> -    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write, skip + size);
>  
>      qemu_iovec_init_external(&elem, iov, niov);
>      qemu_iovec_init(qiov, niov);
> diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> index ab398d0..c830188 100644
> --- a/hw/9pfs/9p.h
> +++ b/hw/9pfs/9p.h
> @@ -348,7 +348,7 @@ struct V9fsTransport {
>      ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
>      ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
>      void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> -                              unsigned int *pniov, bool is_write);
> +                              unsigned int *pniov, bool is_write, size_t size);
>      void        (*push_and_notify)(V9fsPDU *pdu);
>  };
>  
> diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> index e1a37a4..e2b27e8 100644
> --- a/hw/9pfs/virtio-9p-device.c
> +++ b/hw/9pfs/virtio-9p-device.c
> @@ -172,7 +172,7 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
>  }
>  
>  static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> -                              unsigned int *pniov, bool is_write)
> +                              unsigned int *pniov, bool is_write, size_t size)
>  {
>      V9fsState *s = pdu->s;
>      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);

Re: [Qemu-devel] [Xen-devel] [PATCH 2/4] 9pfs: introduce transport specific callbacks

[Stefano Stabellini]

On Thu, 24 Nov 2016, Greg Kurz wrote:
> > > diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> > > index 1782e4a..e1a37a4 100644
> > > --- a/hw/9pfs/virtio-9p-device.c
> > > +++ b/hw/9pfs/virtio-9p-device.c
> > > @@ -20,7 +20,9 @@
> > >  #include "hw/virtio/virtio-access.h"
> > >  #include "qemu/iov.h"
> > >  
> > > -void virtio_9p_push_and_notify(V9fsPDU *pdu)
> > > +static struct V9fsTransport virtio_9p_transport;
> 
> ... shouldn't this be const ?

Yes, makes sense.

Re: [Qemu-devel] [Xen-devel] [PATCH 2/4] 9pfs: introduce transport specific callbacks

[Stefano Stabellini]

On Thu, 24 Nov 2016, Greg Kurz wrote:
> On Thu, 24 Nov 2016 15:23:10 +0100
> Greg Kurz <groug@kaod.org> wrote:
> 
> > On Thu, 24 Nov 2016 09:31:52 +0100
> > Greg Kurz <groug@kaod.org> wrote:
> > 
> > > On Mon, 21 Nov 2016 13:39:30 -0800
> > > Stefano Stabellini <sstabellini@kernel.org> wrote:
> > >   
> > > > Don't call virtio functions from 9pfs generic code, use generic function
> > > > callbacks instead.
> > > > 
> > > > Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> > > > ---    
> > > 
> > > Just a couple of indentation and line over 80 characters nits. I'll fix them
> > > before pushing to 9p-next.
> > > 
> > > Reviewed-by: Greg Kurz <groug@kaod.org>
> > >   
> > 
> > Hmm... second thought...
> > 
> 
> [...]
> 
> > > > +
> > > > +static inline int v9fs_register_transport(V9fsState *s, struct V9fsTransport *t)
> > > > +{
> > > > +    if (s->transport) {
> > > > +        return -EINVAL;
> > > > +    }
> 
> Calling v9fs_register_transport() several times for the same V9fsState looks
> more like a bug than an error...

Yes, you are right. I can turn this into an assert.


> also, is it possible to have several 9pfs
> shares with different transports ?

I think, at least theoretically, is possible. For example Xen HVM
guests, the ones most similar to KVM guests, already support virtio as a
transport. Additionally they will be able to support the Xen based
transport too. (Xen PV guests will only support
the Xen based transport as they don't support virtio in general.)

Re: [Qemu-devel] [PATCH 3/4] 9pfs: use v9fs_init_qiov_from_pdu instead of v9fs_pack

[Stefano Stabellini]

On Thu, 24 Nov 2016, Greg Kurz wrote:
> On Mon, 21 Nov 2016 13:39:31 -0800
> Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> > v9fs_xattr_read should not access VirtQueueElement elems directly.
> > Move v9fs_init_qiov_from_pdu up in the file and call
> > v9fs_init_qiov_from_pdu instead of v9fs_pack.
> > 
> 
> instead of ? I see v9fs_init_qiov_from_pdu() gets called before calling v9fs_pack().

Sorry wrong description. I'll fix it.


> Also, I don't see the corresponding call to qemu_iovec_destroy() to free the
> allocated iovec.

Good point! I'll add a call.


> > Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> > ---
> >  hw/9pfs/9p.c | 58 +++++++++++++++++++++++++++++-----------------------------
> >  1 file changed, 29 insertions(+), 29 deletions(-)
> > 
> > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> > index 5a20a13..b6ec042 100644
> > --- a/hw/9pfs/9p.c
> > +++ b/hw/9pfs/9p.c
> > @@ -1633,14 +1633,39 @@ out_nofid:
> >      pdu_complete(pdu, err);
> >  }
> >  
> > +/*
> > + * Create a QEMUIOVector for a sub-region of PDU iovecs
> > + *
> > + * @qiov:       uninitialized QEMUIOVector
> > + * @skip:       number of bytes to skip from beginning of PDU
> > + * @size:       number of bytes to include
> > + * @is_write:   true - write, false - read
> > + *
> > + * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
> > + * with qemu_iovec_destroy().
> > + */
> > +static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
> > +                                    size_t skip, size_t size,
> > +                                    bool is_write)
> > +{
> > +    QEMUIOVector elem;
> > +    struct iovec *iov;
> > +    unsigned int niov;
> > +
> > +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> > +
> > +    qemu_iovec_init_external(&elem, iov, niov);
> > +    qemu_iovec_init(qiov, niov);
> > +    qemu_iovec_concat(qiov, &elem, skip, size);
> > +}
> > +
> >  static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
> >                             uint64_t off, uint32_t max_count)
> >  {
> >      ssize_t err;
> >      size_t offset = 7;
> >      uint64_t read_count;
> > -    V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
> > -    VirtQueueElement *elem = v->elems[pdu->idx];
> > +    QEMUIOVector qiov_full;
> >  
> >      if (fidp->fs.xattr.len < off) {
> >          read_count = 0;
> > @@ -1656,7 +1681,8 @@ static int v9fs_xattr_read(V9fsState *s, V9fsPDU *pdu, V9fsFidState *fidp,
> >      }
> >      offset += err;
> >  
> > -    err = v9fs_pack(elem->in_sg, elem->in_num, offset,
> > +    v9fs_init_qiov_from_pdu(&qiov_full, pdu, 0, read_count, false);
> > +    err = v9fs_pack(qiov_full.iov, qiov_full.niov, offset,
> >                      ((char *)fidp->fs.xattr.value) + off,
> >                      read_count);
> >      if (err < 0) {
> > @@ -1732,32 +1758,6 @@ static int coroutine_fn v9fs_do_readdir_with_stat(V9fsPDU *pdu,
> >      return count;
> >  }
> >  
> > -/*
> > - * Create a QEMUIOVector for a sub-region of PDU iovecs
> > - *
> > - * @qiov:       uninitialized QEMUIOVector
> > - * @skip:       number of bytes to skip from beginning of PDU
> > - * @size:       number of bytes to include
> > - * @is_write:   true - write, false - read
> > - *
> > - * The resulting QEMUIOVector has heap-allocated iovecs and must be cleaned up
> > - * with qemu_iovec_destroy().
> > - */
> > -static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
> > -                                    size_t skip, size_t size,
> > -                                    bool is_write)
> > -{
> > -    QEMUIOVector elem;
> > -    struct iovec *iov;
> > -    unsigned int niov;
> > -
> > -    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> > -
> > -    qemu_iovec_init_external(&elem, iov, niov);
> > -    qemu_iovec_init(qiov, niov);
> > -    qemu_iovec_concat(qiov, &elem, skip, size);
> > -}
> > -
> >  static void coroutine_fn v9fs_read(void *opaque)
> >  {
> >      int32_t fid;
> 

Re: [Qemu-devel] [PATCH 4/4] 9pfs: add a size parameter to init_iov_from_pdu

[Stefano Stabellini]

On Thu, 24 Nov 2016, Greg Kurz wrote:

> On Mon, 21 Nov 2016 13:39:32 -0800
> Stefano Stabellini <sstabellini@kernel.org> wrote:
> 
> > Not all 9pfs transports share memory between request and response. For
> > those who don't, it is necessary to know how much memory is required in
> > the response.
> > 
> > Signed-off-by: Stefano Stabellini <sstabellini@kernel.org>
> > ---
> 
> IIUC the transport used in Xen requires you pass the size when sending a
> P9_RREAD message back to the guest, i.e. only in the case when is_write is
> false, correct ?

That's right


> If so, for better clarity, what about having two distinct init_in_iov_from_pdu
> and init_out_iov_from_pdu ops, with an explicit comment in the virtio-9p
> implementation of init_in_iov_from_pdu so that someone isn't tempted to drop
> the apparently unused size argument ? Would this be ok for you on the Xen
> side ?

Sure, that's fine by me. I'll do that.


> Cheers.
> 
> --
> Greg
> 
> >  hw/9pfs/9p.c               | 2 +-
> >  hw/9pfs/9p.h               | 2 +-
> >  hw/9pfs/virtio-9p-device.c | 2 +-
> >  3 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/hw/9pfs/9p.c b/hw/9pfs/9p.c
> > index b6ec042..b82212b 100644
> > --- a/hw/9pfs/9p.c
> > +++ b/hw/9pfs/9p.c
> > @@ -1652,7 +1652,7 @@ static void v9fs_init_qiov_from_pdu(QEMUIOVector *qiov, V9fsPDU *pdu,
> >      struct iovec *iov;
> >      unsigned int niov;
> >  
> > -    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write);
> > +    pdu->s->transport->init_iov_from_pdu(pdu, &iov, &niov, is_write, skip + size);
> >  
> >      qemu_iovec_init_external(&elem, iov, niov);
> >      qemu_iovec_init(qiov, niov);
> > diff --git a/hw/9pfs/9p.h b/hw/9pfs/9p.h
> > index ab398d0..c830188 100644
> > --- a/hw/9pfs/9p.h
> > +++ b/hw/9pfs/9p.h
> > @@ -348,7 +348,7 @@ struct V9fsTransport {
> >      ssize_t     (*pdu_vmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
> >      ssize_t     (*pdu_vunmarshal)(V9fsPDU *pdu, size_t offset, const char *fmt, va_list ap);
> >      void        (*init_iov_from_pdu)(V9fsPDU *pdu, struct iovec **piov,
> > -                              unsigned int *pniov, bool is_write);
> > +                              unsigned int *pniov, bool is_write, size_t size);
> >      void        (*push_and_notify)(V9fsPDU *pdu);
> >  };
> >  
> > diff --git a/hw/9pfs/virtio-9p-device.c b/hw/9pfs/virtio-9p-device.c
> > index e1a37a4..e2b27e8 100644
> > --- a/hw/9pfs/virtio-9p-device.c
> > +++ b/hw/9pfs/virtio-9p-device.c
> > @@ -172,7 +172,7 @@ static ssize_t virtio_pdu_vunmarshal(V9fsPDU *pdu, size_t offset,
> >  }
> >  
> >  static void virtio_init_iov_from_pdu(V9fsPDU *pdu, struct iovec **piov,
> > -                              unsigned int *pniov, bool is_write)
> > +                              unsigned int *pniov, bool is_write, size_t size)
> >  {
> >      V9fsState *s = pdu->s;
> >      V9fsVirtioState *v = container_of(s, V9fsVirtioState, state);
>