[libvirt] [PATCH V2] libxl: add default controllers for USB devices

[Jim Fehlig]

On 05/23/2017 01:11 AM, Cedric Bosdonnat wrote:
> On Fri, 2017-05-05 at 15:48 -0600, Jim Fehlig wrote:
>> Attempting to start a domain with USB hostdevs but no USB controllers
>> fails with the rather cryptic error
>>
>> libxl: error: libxl_qmp.c:287:qmp_handle_error_response: received an
>> error message from QMP server: Bus 'xenusb-0.0' not found
>>
>> This can be fixed by creating default USB controllers. When no USB
>> controllers are defined, create the number of 8 port controllers
>> necessary to accommodate the number of defined USB devices.
>>
>> Note that USB controllers are already created as needed in the
>> domainAttachDevice code path. E.g. a USB controller will be created,
>> if necessary, when attaching a USB device with
>> 'virsh attach-device dom usbdev.xml'.
>>
>> Signed-off-by: Jim Fehlig <jfehlig at suse.com>
>> ---
>>
>> V1 here
>>
>> https://www.redhat.com/archives/libvir-list/2017-April/msg00965.html
>>
>> While further testing of V1 found a libvirtd segfault due to
>> incorrectly using virDomainControllerInsertPreAlloced instead of
>> virDomainControllerInsert.
>>
>>   src/libxl/libxl_conf.c | 82 +++++++++++++++++++++++++++++++++++++++++++-------
>>   1 file changed, 71 insertions(+), 11 deletions(-)
>>
>> diff --git a/src/libxl/libxl_conf.c b/src/libxl/libxl_conf.c
>> index 56bc09719..cdf6ec9f3 100644
>> --- a/src/libxl/libxl_conf.c
>> +++ b/src/libxl/libxl_conf.c
>> @@ -1822,34 +1822,94 @@ libxlMakeUSBController(virDomainControllerDefPtr controller,
>>   }
>>   
>>   static int
>> +libxlMakeDefaultUSBControllers(virDomainDefPtr def,
>> +                               libxl_domain_config *d_config)
>> +{
>> +    virDomainControllerDefPtr l_controller = NULL;
>> +    libxl_device_usbctrl *x_controllers = NULL;
>> +    size_t nusbdevs = 0;
>> +    size_t ncontrollers;
>> +    size_t i;
>> +
>> +    for (i = 0; i < def->nhostdevs; i++) {
>> +        if (def->hostdevs[i]->mode == VIR_DOMAIN_HOSTDEV_MODE_SUBSYS &&
>> +            def->hostdevs[i]->source.subsys.type == VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_USB)
>> +            nusbdevs++;
>> +    }
>> +
>> +    /* No controllers needed if there are no USB devs */
>> +    if (nusbdevs == 0)
>> +        return 0;
>> +
>> +    /* Create USB controllers with 8 ports */
>> +    ncontrollers = VIR_DIV_UP(nusbdevs, 8);
>> +    if (VIR_ALLOC_N(x_controllers, ncontrollers) < 0)
>> +        return -1;
>> +
>> +    for (i = 0; i < ncontrollers; i++) {
>> +        if (!(l_controller = virDomainControllerDefNew(VIR_DOMAIN_CONTROLLER_TYPE_USB)))
>> +            goto error;
>> +
>> +        l_controller->model = VIR_DOMAIN_CONTROLLER_MODEL_USB_QUSB2;
>> +        l_controller->idx = i;
>> +        l_controller->opts.usbopts.ports = 8;
>> +
>> +        libxl_device_usbctrl_init(&x_controllers[i]);
>> +
>> +        if (libxlMakeUSBController(l_controller, &x_controllers[i]) < 0)
>> +            goto error;
>> +
>> +        if (virDomainControllerInsert(def, l_controller) < 0)
>> +            goto error;
>> +
>> +        l_controller = NULL;
>> +    }
>> +
>> +    d_config->usbctrls = x_controllers;
>> +    d_config->num_usbctrls = ncontrollers;
>> +    return 0;
>> +
>> + error:
>> +     virDomainControllerDefFree(l_controller);
>> +     for (i = 0; i < ncontrollers; i++)
>> +         libxl_device_usbctrl_dispose(&x_controllers[i]);
>> +     VIR_FREE(x_controllers);
>> +     return -1;
>> +}
>> +
>> +static int
>>   libxlMakeUSBControllerList(virDomainDefPtr def, libxl_domain_config *d_config)
>>   {
>>       virDomainControllerDefPtr *l_controllers = def->controllers;
>>       size_t ncontrollers = def->ncontrollers;
>>       size_t nusbctrls = 0;
>>       libxl_device_usbctrl *x_usbctrls;
>> -    size_t i;
>> -
>> -    if (ncontrollers == 0)
>> -        return 0;
>> -
>> -    if (VIR_ALLOC_N(x_usbctrls, ncontrollers) < 0)
>> -        return -1;
>> +    size_t i, j;
>>   
>>       for (i = 0; i < ncontrollers; i++) {
>> +        if (l_controllers[i]->type == VIR_DOMAIN_CONTROLLER_TYPE_USB)
>> +            nusbctrls++;
>> +    }
>> +
>> +    if (nusbctrls == 0)
>> +        return libxlMakeDefaultUSBControllers(def, d_config);
>> +
>> +    if (VIR_ALLOC_N(x_usbctrls, nusbctrls) < 0)
>> +        return -1;
>> +
>> +    for (i = 0, j = 0; i < ncontrollers && j < nusbctrls; i++) {
>>           if (l_controllers[i]->type != VIR_DOMAIN_CONTROLLER_TYPE_USB)
>>               continue;
>>   
>> -        libxl_device_usbctrl_init(&x_usbctrls[nusbctrls]);
>> +        libxl_device_usbctrl_init(&x_usbctrls[j]);
>>   
>>           if (libxlMakeUSBController(l_controllers[i],
>> -                                   &x_usbctrls[nusbctrls]) < 0)
>> +                                   &x_usbctrls[j]) < 0)
>>               goto error;
>>   
>> -        nusbctrls++;
>> +        j++;
>>       }
>>   
>> -    VIR_SHRINK_N(x_usbctrls, ncontrollers, ncontrollers - nusbctrls);
>>       d_config->usbctrls = x_usbctrls;
>>       d_config->num_usbctrls = nusbctrls;
>>   
> 
> ACK

Cool, thanks for taking a look! Pushed now.

Regards,
Jim