Re: [Qemu-devel] [RFC PATCH for 2.11] tests: Introduce generic device hot-plug/hot-unplug functions

[Peter Xu]

On Tue, Aug 15, 2017 at 11:22:44AM +0200, Thomas Huth wrote:
> A lot of tests provide code for adding and removing a device via the
> device_add and device_del QMP commands. Maintaining this code in so
> many places is cumbersome and error-prone (some of the code parts
> check the responses in an incorrect way, for example), so let's
> provide some proper generic qtest functions for adding and removing a
> device instead.
> 
> Signed-off-by: Thomas Huth <address@hidden>
> ---
>  I'm planning to use qtest_hot_plug_device() in a bigger patch series
>  that I'm currently preparing. But since this clean-up patch is valid on
>  its own already, I'd like to get some feedback (or even a Reviewed-by)
>  for this patch here already if possible...
> 
>  tests/libqos/pci.c         | 19 ++-------------
>  tests/libqos/usb.c         | 30 +++++------------------
>  tests/libqtest.c           | 60 
> ++++++++++++++++++++++++++++++++++++++++++++++
>  tests/libqtest.h           | 19 +++++++++++++++
>  tests/usb-hcd-uhci-test.c  | 26 ++------------------
>  tests/usb-hcd-xhci-test.c  | 52 ++++------------------------------------
>  tests/virtio-scsi-test.c   | 24 ++-----------------
>  tests/virtio-serial-test.c | 25 +++----------------
>  8 files changed, 98 insertions(+), 157 deletions(-)
> 
> diff --git a/tests/libqos/pci.c b/tests/libqos/pci.c
> index 2dcdead..aada753 100644
> --- a/tests/libqos/pci.c
> +++ b/tests/libqos/pci.c
> @@ -394,21 +394,6 @@ QPCIBar qpci_legacy_iomap(QPCIDevice *dev, uint16_t addr)
>  void qpci_plug_device_test(const char *driver, const char *id,
>                             uint8_t slot, const char *opts)
>  {
> -    QDict *response;
> -    char *cmd;
> -
> -    cmd = g_strdup_printf("{'execute': 'device_add',"
> -                          " 'arguments': {"
> -                          "   'driver': '%s',"
> -                          "   'addr': '%d',"
> -                          "   %s%s"
> -                          "   'id': '%s'"
> -                          "}}", driver, slot,
> -                          opts ? opts : "", opts ? "," : "",
> -                          id);
> -    response = qmp(cmd);
> -    g_free(cmd);
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> +    qtest_hot_plug_device(driver, id, "'addr': '%d'%s%s", slot,
> +                          opts ? ", " : "", opts ? opts : "");
>  }
> diff --git a/tests/libqos/usb.c b/tests/libqos/usb.c
> index 0cdfaec..f8d0190 100644
> --- a/tests/libqos/usb.c
> +++ b/tests/libqos/usb.c
> @@ -40,34 +40,16 @@ void uhci_port_test(struct qhc *hc, int port, uint16_t 
> expect)
>  void usb_test_hotplug(const char *hcd_id, const int port,
>                        void (*port_check)(void))
>  {
> -    QDict *response;
> -    char  *cmd;
> +    char  *id = g_strdup_printf("usbdev%d", port);
>  
> -    cmd = g_strdup_printf("{'execute': 'device_add',"
> -                          " 'arguments': {"
> -                          "   'driver': 'usb-tablet',"
> -                          "   'port': '%d',"
> -                          "   'bus': '%s.0',"
> -                          "   'id': 'usbdev%d'"
> -                          "}}", port, hcd_id, port);
> -    response = qmp(cmd);
> -    g_free(cmd);
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> +    qtest_hot_plug_device("usb-tablet", id, "'port': '%d', 'bus': '%s.0'",
> +                          port, hcd_id);
>  
>      if (port_check) {
>          port_check();
>      }
>  
> -    cmd = g_strdup_printf("{'execute': 'device_del',"
> -                           " 'arguments': {"
> -                           "   'id': 'usbdev%d'"
> -                           "}}", port);
> -    response = qmp(cmd);
> -    g_free(cmd);
> -    g_assert(response);
> -    g_assert(qdict_haskey(response, "event"));
> -    g_assert(!strcmp(qdict_get_str(response, "event"), "DEVICE_DELETED"));
> -    QDECREF(response);
> +    qtest_hot_unplug_device(id);
> +
> +    g_free(id);
>  }
> diff --git a/tests/libqtest.c b/tests/libqtest.c
> index b9a1f18..4339d97 100644
> --- a/tests/libqtest.c
> +++ b/tests/libqtest.c
> @@ -987,3 +987,63 @@ void qtest_cb_for_every_machine(void (*cb)(const char 
> *machine))
>      qtest_end();
>      QDECREF(response);
>  }
> +
> +/**
> + * Generic hot-plugging test via the device_add QMP command
> + */
> +void qtest_hot_plug_device(const char *driver, const char *id,
> +                           const char *fmt, ...)
> +{
> +    QDict *response;
> +    char *cmd, *opts = NULL;
> +    va_list va;
> +
> +    if (fmt) {
> +        va_start(va, fmt);
> +        opts = g_strdup_vprintf(fmt, va);
> +        va_end(va);
> +    }
> +
> +    cmd = g_strdup_printf("{'execute': 'device_add',"
> +                          " 'arguments': { 'driver': '%s', 'id': '%s'%s%s 
> }}",
> +                          driver, id, opts ? ", " : "", opts ? opts : "");
> +    g_free(opts);
> +
> +    response = qmp(cmd);
> +    g_free(cmd);
> +    g_assert(response);
> +    while (qdict_haskey(response, "event")) {
> +        /* We can get DEVICE_DELETED events in case something went wrong */
> +        g_assert_cmpstr(qdict_get_str(response, "event"), !=, 
> "DEVICE_DELETED");
> +        QDECREF(response);
> +        response = qmp("");
> +        g_assert(response);
> +    }

I guess we don't need this block for hot plug? :-)

> +    g_assert(!qdict_haskey(response, "error"));
> +    QDECREF(response);
> +}
> +
> +/**
> + * Generic hot-unplugging test via the device_del QMP command
> + */
> +void qtest_hot_unplug_device(const char *id)
> +{
> +    QDict *response;
> +    char *cmd;
> +
> +    cmd = g_strdup_printf("{'execute': 'device_del',"
> +                          " 'arguments': { 'id': '%s' }}", id);
> +
> +    response = qmp(cmd);
> +    g_free(cmd);
> +    g_assert(response);
> +    while (qdict_haskey(response, "event")) {
> +        /* We should get DEVICE_DELETED event first */

So here is the mis-order thing: could the "return: {}" arrive earlier?
IHMO it can.  If so, we'll leave the event in the buffer without
reading it.

If you see my patch, I do two reads (assuming we will only get exactly
one "return: {}" and a DELETED event), and take care of the ordering.
Would that be better?

> +        g_assert_cmpstr(qdict_get_str(response, "event"), ==, 
> "DEVICE_DELETED");
> +        QDECREF(response);
> +        response = qmp("");
> +        g_assert(response);
> +    }
> +    g_assert(!qdict_haskey(response, "error"));
> +    QDECREF(response);
> +}
> diff --git a/tests/libqtest.h b/tests/libqtest.h
> index 3ae5709..9c1006f 100644
> --- a/tests/libqtest.h
> +++ b/tests/libqtest.h
> @@ -927,4 +927,23 @@ QDict *qmp_fd(int fd, const char *fmt, ...);
>   */
>  void qtest_cb_for_every_machine(void (*cb)(const char *machine));
>  
> +/**
> + * qtest_hot_plug_device:
> + * @driver: Name of the device that should be added
> + * @id: Identification string
> + * @fmt: printf-like format string for further options to device_add
> + *
> + * Generic hot-plugging test via the device_add QMP command.
> + */
> +void qtest_hot_plug_device(const char *driver, const char *id,
> +                           const char *fmt, ...) GCC_FMT_ATTR(3, 4);
> +
> +/**
> + * qtest_hot_unplug_device:
> + * @id: Identification string
> + *
> + * Generic hot-unplugging test via the device_del QMP command.
> + */
> +void qtest_hot_unplug_device(const char *id);
> +
>  #endif
> diff --git a/tests/usb-hcd-uhci-test.c b/tests/usb-hcd-uhci-test.c
> index 5b500fe..7465bfd 100644
> --- a/tests/usb-hcd-uhci-test.c
> +++ b/tests/usb-hcd-uhci-test.c
> @@ -48,31 +48,9 @@ static void test_uhci_hotplug(void)
>  
>  static void test_usb_storage_hotplug(void)
>  {
> -    QDict *response;
> +    qtest_hot_plug_device("usb-storage", "usbdev0", "'drive': 'drive0'");
>  
> -    response = qmp("{'execute': 'device_add',"
> -                   " 'arguments': {"
> -                   "   'driver': 'usb-storage',"
> -                   "   'drive': 'drive0',"
> -                   "   'id': 'usbdev0'"
> -                   "}}");
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("{'execute': 'device_del',"
> -                           " 'arguments': {"
> -                           "   'id': 'usbdev0'"
> -                           "}}");
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("");
> -    g_assert(response);
> -    g_assert(qdict_haskey(response, "event"));
> -    g_assert(!strcmp(qdict_get_str(response, "event"), "DEVICE_DELETED"));
> -    QDECREF(response);
> +    qtest_hot_unplug_device("usbdev0");
>  }
>  
>  int main(int argc, char **argv)
> diff --git a/tests/usb-hcd-xhci-test.c b/tests/usb-hcd-xhci-test.c
> index 031764d..ae89362 100644
> --- a/tests/usb-hcd-xhci-test.c
> +++ b/tests/usb-hcd-xhci-test.c
> @@ -11,7 +11,6 @@
>  #include "libqtest.h"
>  #include "libqos/usb.h"
>  
> -

Nit: useless change

Other than these, it looks quite good to me.  Thanks,

>  static void test_xhci_init(void)
>  {
>  }
> @@ -23,59 +22,16 @@ static void test_xhci_hotplug(void)
>  
>  static void test_usb_uas_hotplug(void)
>  {
> -    QDict *response;
> -
> -    response = qmp("{'execute': 'device_add',"
> -                   " 'arguments': {"
> -                   "   'driver': 'usb-uas',"
> -                   "   'id': 'uas'"
> -                   "}}");
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("{'execute': 'device_add',"
> -                   " 'arguments': {"
> -                   "   'driver': 'scsi-hd',"
> -                   "   'drive': 'drive0',"
> -                   "   'id': 'scsi-hd'"
> -                   "}}");
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> +    qtest_hot_plug_device("usb-uas", "uas", NULL);
> +    qtest_hot_plug_device("scsi-hd", "scsihd", "'drive': 'drive0'");
>  
>      /* TODO:
>          UAS HBA driver in libqos, to check that
>          added disk is visible after BUS rescan
>      */
>  
> -    response = qmp("{'execute': 'device_del',"
> -                           " 'arguments': {"
> -                           "   'id': 'scsi-hd'"
> -                           "}}");
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("");
> -    g_assert(qdict_haskey(response, "event"));
> -    g_assert(!strcmp(qdict_get_str(response, "event"), "DEVICE_DELETED"));
> -    QDECREF(response);
> -
> -
> -    response = qmp("{'execute': 'device_del',"
> -                           " 'arguments': {"
> -                           "   'id': 'uas'"
> -                           "}}");
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("");
> -    g_assert(response);
> -    g_assert(qdict_haskey(response, "event"));
> -    g_assert(!strcmp(qdict_get_str(response, "event"), "DEVICE_DELETED"));
> -    QDECREF(response);
> +    qtest_hot_unplug_device("scsihd");
> +    qtest_hot_unplug_device("uas");
>  }
>  
>  int main(int argc, char **argv)
> diff --git a/tests/virtio-scsi-test.c b/tests/virtio-scsi-test.c
> index 87a3b6e..6e7ba6f 100644
> --- a/tests/virtio-scsi-test.c
> +++ b/tests/virtio-scsi-test.c
> @@ -192,32 +192,12 @@ static void pci_nop(void)
>  
>  static void hotplug(void)
>  {
> -    QDict *response;
>      QOSState *qs;
>  
>      qs = qvirtio_scsi_start(
>              "-drive id=drv1,if=none,file=null-co://,format=raw");
> -    response = qmp("{\"execute\": \"device_add\","
> -                   " \"arguments\": {"
> -                   "   \"driver\": \"scsi-hd\","
> -                   "   \"id\": \"scsi-hd\","
> -                   "   \"drive\": \"drv1\""
> -                   "}}");
> -
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("{\"execute\": \"device_del\","
> -                   " \"arguments\": {"
> -                   "   \"id\": \"scsi-hd\""
> -                   "}}");
> -
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    g_assert(qdict_haskey(response, "event"));
> -    g_assert(!strcmp(qdict_get_str(response, "event"), "DEVICE_DELETED"));
> -    QDECREF(response);
> +    qtest_hot_plug_device("scsi-hd", "scsihd", "'drive': 'drv1'");
> +    qtest_hot_unplug_device("scsihd");
>      qvirtio_scsi_stop(qs);
>  }
>  
> diff --git a/tests/virtio-serial-test.c b/tests/virtio-serial-test.c
> index b14d943..97f8f52 100644
> --- a/tests/virtio-serial-test.c
> +++ b/tests/virtio-serial-test.c
> @@ -17,28 +17,9 @@ static void pci_nop(void)
>  
>  static void hotplug(void)
>  {
> -    QDict *response;
> -
> -    response = qmp("{\"execute\": \"device_add\","
> -                   " \"arguments\": {"
> -                   "   \"driver\": \"virtserialport\","
> -                   "   \"id\": \"hp-port\""
> -                   "}}");
> -
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    QDECREF(response);
> -
> -    response = qmp("{\"execute\": \"device_del\","
> -                   " \"arguments\": {"
> -                   "   \"id\": \"hp-port\""
> -                   "}}");
> -
> -    g_assert(response);
> -    g_assert(!qdict_haskey(response, "error"));
> -    g_assert(qdict_haskey(response, "event"));
> -    g_assert(!strcmp(qdict_get_str(response, "event"), "DEVICE_DELETED"));
> -    QDECREF(response);
> +    qtest_hot_plug_device("virtserialport", "hp-port", NULL);
> +
> +    qtest_hot_unplug_device("hp-port");
>  }
>  
>  int main(int argc, char **argv)
> -- 
> 1.8.3.1
> 
> 

-- 
Peter Xu