On Thu, Dec 24, 2020 at 08:14:31AM -0600, Jonathon Jongsma wrote:
> At startup, query devices that are defined by 'mdevctl' and add them to
> the node device list.
>
> This adds a complication: we now have two potential sources of
> information for a node device:
> - udev for all devices and for activated mediated devices
> - mdevctl for persistent mediated devices
>
> Unfortunately, neither backend returns full information for a mediated
> device. For example, if a persistent mediated device in the list (with
> information provided from mdevctl) is 'started', that same device will
> now be detected by udev. If we simply overwrite the existing device
> definition with the new one provided by the udev backend, we will lose
> extra information that was provided by mdevctl (e.g. attributes, etc).
> To avoid this, make sure to copy the extra information into the new
> device definition.
>
> Signed-off-by: Jonathon Jongsma <jjongsma@xxxxxxxxxx>
> ---
> src/node_device/node_device_driver.c | 76 ++++++++++++++++++++++++++++
> src/node_device/node_device_driver.h | 3 ++
> src/node_device/node_device_udev.c | 48 ++++++++++++++++++
> 3 files changed, 127 insertions(+)
>
> diff --git a/src/node_device/node_device_driver.c b/src/node_device/node_device_driver.c
> index 5309b8abd5..0267005af1 100644
> --- a/src/node_device/node_device_driver.c
> +++ b/src/node_device/node_device_driver.c
> @@ -1144,3 +1144,79 @@ nodeDeviceGenerateName(virNodeDeviceDefPtr def,
> *(def->name + i) = '_';
> }
> }
> +
> +
> +static int
> +virMdevctlListDefined(virNodeDeviceDefPtr **devs)
> +{
> + int status;
> + g_autofree char *output = NULL;
> + g_autoptr(virCommand) cmd = nodeDeviceGetMdevctlListCommand(true, &output);
> +
> + if (virCommandRun(cmd, &status) < 0)
> + return -1;
> +
> + if (!output)
> + return -1;
> +
> + return nodeDeviceParseMdevctlJSON(output, devs);
> +}
> +
> +
> +int
> +nodeDeviceUpdateMediatedDevices(void)
> +{
> + g_autofree virNodeDeviceDefPtr *devs = NULL;
> + int ndevs;
> + size_t i;
> +
> + if ((ndevs = virMdevctlListDefined(&devs)) < 0) {
> + virReportSystemError(errno, "%s",
> + _("failed to query mdevs from mdevctl"));
> + return -1;
> + }
> +
> + for (i = 0; i < ndevs; i++) {
> + virNodeDeviceObjPtr obj;
> + virObjectEventPtr event;
> + virNodeDeviceDefPtr dev = devs[i];
> + bool new_device = true;
> +
> + dev->driver = g_strdup("vfio_mdev");
> +
> + /* If a device defined by mdevctl is already in the list, that means
> + * that it was found via the normal device discovery process and thus
> + * is already activated. Active devices contain some additional
> + * information (e.g. sysfs path) that is not provided by mdevctl, so
> + * preserve that info */
> + if ((obj = virNodeDeviceObjListFindByName(driver->devs, dev->name))) {
> + virNodeDeviceDefPtr olddef = virNodeDeviceObjGetDef(obj);
> +
> + /* Copy any data from the existing device */
> + dev->sysfs_path = g_strdup(olddef->sysfs_path);
> + dev->parent_sysfs_path = g_strdup(olddef->parent_sysfs_path);
> + dev->driver = g_strdup(olddef->driver);
> + dev->devnode = g_strdup(olddef->devnode);
> + dev->caps->data.mdev.iommuGroupNumber = olddef->caps->data.mdev.iommuGroupNumber;
> +
> + virNodeDeviceObjEndAPI(&obj);
> + new_device = false;
> + }
> +
> + if (!(obj = virNodeDeviceObjListAssignDef(driver->devs, dev))) {
> + virNodeDeviceDefFree(dev);
> + return -1;
> + }
> +
> + if (new_device)
> + event = virNodeDeviceEventLifecycleNew(dev->name,
> + VIR_NODE_DEVICE_EVENT_CREATED,
> + 0);
As mentioned in the other patch, we need to have DEFINED/UNDEFINED
events. In fact this method doens't seem to remove existing mdevs
that no longer exist.
> + else
> + event = virNodeDeviceEventUpdateNew(dev->name);
This is triggering events for all devices every time any single device
changes, even if those devices have no changes.
Regards,
Daniel
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