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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Minios-devel] [UNIKRAFT PATCH v4 6/7] plat/xen: Add Xenbus device probing
Reviewed-by: Yuri Volchkov <yuri.volchkov@xxxxxxxxx>
Costin Lupu <costin.lupu@xxxxxxxxx> writes:
> Extend the Xenbus bus driver with support for probing Xenbus
> devices.
>
> Signed-off-by: Costin Lupu <costin.lupu@xxxxxxxxx>
> ---
> plat/xen/include/xenbus/client.h | 12 ++++
> plat/xen/include/xenbus/xenbus.h | 17 ++++-
> plat/xen/xenbus/client.c | 12 ++++
> plat/xen/xenbus/exportsyms.uk | 1 +
> plat/xen/xenbus/xenbus.c | 131
> ++++++++++++++++++++++++++++++++++++++-
> 5 files changed, 171 insertions(+), 2 deletions(-)
>
> diff --git a/plat/xen/include/xenbus/client.h
> b/plat/xen/include/xenbus/client.h
> index f3540b7..8b7e8c1 100644
> --- a/plat/xen/include/xenbus/client.h
> +++ b/plat/xen/include/xenbus/client.h
> @@ -86,4 +86,16 @@ int xenbus_watch_wait_event(struct xenbus_watch *watch);
> */
> int xenbus_watch_notify_event(struct xenbus_watch *watch);
>
> +/*
> + * Driver states
> + */
> +
> +/*
> + * Returns the driver state found at the given Xenstore path.
> + *
> + * @param path Xenstore path
> + * @return The Xenbus driver state
> + */
> +XenbusState xenbus_read_driver_state(const char *path);
> +
> #endif /* __XENBUS_CLIENT_H__ */
> diff --git a/plat/xen/include/xenbus/xenbus.h
> b/plat/xen/include/xenbus/xenbus.h
> index 230dcd4..3d3b540 100644
> --- a/plat/xen/include/xenbus/xenbus.h
> +++ b/plat/xen/include/xenbus/xenbus.h
> @@ -110,7 +110,22 @@ UK_TAILQ_HEAD(xenbus_watch_list, struct xenbus_watch);
> */
>
> struct xenbus_device {
> -
> + /**< in use by Xenbus handler */
> + UK_TAILQ_ENTRY(struct xenbus_device) next;
> + /**< Device state */
> + XenbusState state;
> + /**< Device type */
> + enum xenbus_dev_type devtype;
> + /**< Xenstore path of the device */
> + char *nodename;
> + /**< Xenstore path of the device peer (e.g. backend for frontend) */
> + char *otherend;
> + /**< Domain id of the other end */
> + domid_t otherend_id;
> + /**< Watch for monitoring changes on other end */
> + struct xenbus_watch *otherend_watch;
> + /**< Xenbus driver */
> + struct xenbus_driver *drv;
> };
> UK_TAILQ_HEAD(xenbus_device_list, struct xenbus_device);
>
> diff --git a/plat/xen/xenbus/client.c b/plat/xen/xenbus/client.c
> index 3dbca0f..274e6e7 100644
> --- a/plat/xen/xenbus/client.c
> +++ b/plat/xen/xenbus/client.c
> @@ -44,6 +44,7 @@
> #include <string.h>
> #include <uk/errptr.h>
> #include <uk/wait.h>
> +#include <xenbus/xs.h>
> #include <xenbus/client.h>
>
>
> @@ -130,3 +131,14 @@ int xenbus_watch_notify_event(struct xenbus_watch *watch)
>
> return 0;
> }
> +
> +XenbusState xenbus_read_driver_state(const char *path)
> +{
> + char state_path[strlen(path) + sizeof("/state")];
> + XenbusState state = XenbusStateUnknown;
> +
> + sprintf(state_path, "%s/state", path);
> + xs_read_integer(XBT_NIL, state_path, (int *) &state);
> +
> + return state;
> +}
> diff --git a/plat/xen/xenbus/exportsyms.uk b/plat/xen/xenbus/exportsyms.uk
> index a424fd9..d57a2a5 100644
> --- a/plat/xen/xenbus/exportsyms.uk
> +++ b/plat/xen/xenbus/exportsyms.uk
> @@ -27,3 +27,4 @@ xenbus_state_to_str
> xenbus_devtype_to_str
> xenbus_str_to_devtype
> xenbus_watch_wait_event
> +xenbus_read_driver_state
> diff --git a/plat/xen/xenbus/xenbus.c b/plat/xen/xenbus/xenbus.c
> index a20546b..28f0cfd 100644
> --- a/plat/xen/xenbus/xenbus.c
> +++ b/plat/xen/xenbus/xenbus.c
> @@ -43,8 +43,12 @@
> #include <uk/errptr.h>
> #include <uk/assert.h>
> #include <xenbus/xenbus.h>
> +#include <xenbus/xs.h>
> +#include <xenbus/client.h>
> #include "xs_comms.h"
>
> +#define XS_DEV_PATH "device"
> +
> static struct xenbus_handler xbh;
>
>
> @@ -67,13 +71,138 @@ void uk_xb_free(void *ptr)
> uk_free(xbh.a, ptr);
> }
>
> +
> +static struct xenbus_driver *xenbus_find_driver(xenbus_dev_type_t devtype)
> +{
> + struct xenbus_driver *drv;
> + const xenbus_dev_type_t *pdevtype;
> +
> + UK_TAILQ_FOREACH(drv, &xbh.drv_list, next) {
> + for (pdevtype = drv->device_types;
> + *pdevtype != xenbus_dev_none; pdevtype++) {
> + if (*pdevtype == devtype)
> + return drv;
> + }
> + }
> +
> + return NULL; /* no driver found */
> +}
> +
> +static int xenbus_probe_device(struct xenbus_driver *drv,
> + xenbus_dev_type_t type, const char *name)
> +{
> + int err;
> + struct xenbus_device *dev;
> + char *nodename = NULL;
> + XenbusState state;
> +
> + /* device/type/name */
> + err = asprintf(&nodename, "%s/%s/%s",
> + XS_DEV_PATH, xenbus_devtype_to_str(type), name);
> + if (err < 0)
> + goto out;
> +
> + state = xenbus_read_driver_state(nodename);
> + if (state != XenbusStateInitialising)
> + return 0;
> +
> + uk_printd(DLVL_INFO, "Xenbus device: %s\n", nodename);
> +
> + dev = uk_xb_calloc(1, sizeof(*dev) + strlen(nodename) + 1);
> + if (!dev) {
> + uk_printd(DLVL_ERR, "Failed to initialize: Out of memory!\n");
> + err = -ENOMEM;
> + goto out;
> + }
> +
> + dev->state = XenbusStateInitialising;
> + dev->devtype = type;
> + dev->nodename = (char *) (dev + 1);
> + strcpy(dev->nodename, nodename);
> +
> + err = drv->add_dev(dev);
> + if (err) {
> + uk_printd(DLVL_ERR, "Failed to add device.\n");
> + uk_xb_free(dev);
> + }
> +
> +out:
> + if (nodename)
> + free(nodename);
> +
> + return err;
> +}
> +
> +static int xenbus_probe_device_type(const char *devtype_str)
> +{
> + struct xenbus_driver *drv;
> + xenbus_dev_type_t devtype;
> + char dirname[sizeof(XS_DEV_PATH) + strlen(devtype_str)];
> + char **devices = NULL;
> + int err = 0;
> +
> + devtype = xenbus_str_to_devtype(devtype_str);
> + if (!devtype) {
> + uk_printd(DLVL_WARN,
> + "Unsupported device type: %s\n", devtype_str);
> + goto out;
> + }
> +
> + drv = xenbus_find_driver(devtype);
> + if (!drv) {
> + uk_printd(DLVL_WARN,
> + "No driver for device type: %s\n", devtype_str);
> + goto out;
> + }
> +
> + sprintf(dirname, "%s/%s", XS_DEV_PATH, devtype_str);
> +
> + /* Get device list */
> + devices = xs_ls(XBT_NIL, dirname);
> + if (PTRISERR(devices)) {
> + err = PTR2ERR(devices);
> + uk_printd(DLVL_ERR,
> + "Error reading %s devices: %d\n", devtype_str, err);
> + goto out;
> + }
> +
> + for (int i = 0; devices[i] != NULL; i++) {
> + /* Probe only if no prior error */
> + if (err == 0)
> + err = xenbus_probe_device(drv, devtype, devices[i]);
> + }
> +
> +out:
> + if (!PTRISERR(devices))
> + free(devices);
> +
> + return err;
> +}
> +
> static int xenbus_probe(void)
> {
> + char **devtypes;
> int err = 0;
>
> uk_printd(DLVL_INFO, "Probe Xenbus\n");
>
> - /* TODO */
> + /* Get device types list */
> + devtypes = xs_ls(XBT_NIL, XS_DEV_PATH);
> + if (PTRISERR(devtypes)) {
> + err = PTR2ERR(devtypes);
> + uk_printd(DLVL_ERR, "Error reading device types: %d\n", err);
> + goto out;
> + }
> +
> + for (int i = 0; devtypes[i] != NULL; i++) {
> + /* Probe only if no previous error */
> + if (err == 0)
> + err = xenbus_probe_device_type(devtypes[i]);
> + }
> +
> +out:
> + if (!PTRISERR(devtypes))
> + free(devtypes);
>
> return err;
> }
> --
> 2.11.0
>
--
Yuri Volchkov
Software Specialist
NEC Europe Ltd
Kurfürsten-Anlage 36
D-69115 Heidelberg
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