Commit 637c53ff authored by Juergen Gross's avatar Juergen Gross Committed by Gerd Hoffmann
Browse files

xen: write information about supported backends 



Add a Xenstore directory for each supported pv backend. This will allow
Xen tools to decide which backend type to use in case there are
multiple possibilities.

The information is added under
/local/domain/<backend-domid>/device-model/<domid>/backends
before the "running" state is written to Xenstore. Using a directory
for each backend enables us to add parameters for specific backends
in the future.

This interface is documented in the Xen source repository in the file
docs/misc/qemu-backends.txt

In order to reuse the Xenstore directory creation already present in
hw/xen/xen_devconfig.c move the related functions to
hw/xen/xen_backend.c where they fit better.

Signed-off-by: default avatarJuergen Gross <jgross@suse.com>
Acked-by: default avatarAnthony PERARD <anthony.perard@citrix.com>
Reviewed-by: default avatarWei Liu <wei.liu2@citrix.com>
Message-id: 1463062421-613-3-git-send-email-jgross@suse.com
Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent 9432e53a

hw/xen/xen_backend.c

+63 −0
Original line number Diff line number Diff line
@@ -42,11 +42,36 @@ struct xs_handle *xenstore = NULL; 
const char *xen_protocol;



/* private */

struct xs_dirs {

    char *xs_dir;

    QTAILQ_ENTRY(xs_dirs) list;

};

static QTAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup =

    QTAILQ_HEAD_INITIALIZER(xs_cleanup);



static QTAILQ_HEAD(XenDeviceHead, XenDevice) xendevs = QTAILQ_HEAD_INITIALIZER(xendevs);

static int debug = 0;



/* ------------------------------------------------------------- */



static void xenstore_cleanup_dir(char *dir)

{

    struct xs_dirs *d;



    d = g_malloc(sizeof(*d));

    d->xs_dir = dir;

    QTAILQ_INSERT_TAIL(&xs_cleanup, d, list);

}



void xen_config_cleanup(void)

{

    struct xs_dirs *d;



    QTAILQ_FOREACH(d, &xs_cleanup, list) {

        xs_rm(xenstore, 0, d->xs_dir);

    }

}



int xenstore_write_str(const char *base, const char *node, const char *val)

{

    char abspath[XEN_BUFSIZE];
@@ -75,6 +100,30 @@ char *xenstore_read_str(const char *base, const char *node) 
    return ret;

}



int xenstore_mkdir(char *path, int p)

{

    struct xs_permissions perms[2] = {

        {

            .id    = 0, /* set owner: dom0 */

        }, {

            .id    = xen_domid,

            .perms = p,

        }

    };



    if (!xs_mkdir(xenstore, 0, path)) {

        xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", path);

        return -1;

    }

    xenstore_cleanup_dir(g_strdup(path));



    if (!xs_set_permissions(xenstore, 0, path, perms, 2)) {

        xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", path);

        return -1;

    }

    return 0;

}



int xenstore_write_int(const char *base, const char *node, int ival)

{

    char val[12];
@@ -726,6 +775,20 @@ err: 


int xen_be_register(const char *type, struct XenDevOps *ops)

{

    char path[50];

    int rc;



    if (ops->backend_register) {

        rc = ops->backend_register();

        if (rc) {

            return rc;

        }

    }



    snprintf(path, sizeof(path), "device-model/%u/backends/%s", xen_domid,

             type);

    xenstore_mkdir(path, XS_PERM_NONE);



    return xenstore_scan(type, xen_domid, ops);

}

hw/xen/xen_devconfig.c

+2 −50
Original line number Diff line number Diff line
@@ -5,54 +5,6 @@ 


/* ------------------------------------------------------------- */



struct xs_dirs {

    char *xs_dir;

    QTAILQ_ENTRY(xs_dirs) list;

};

static QTAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup = QTAILQ_HEAD_INITIALIZER(xs_cleanup);



static void xen_config_cleanup_dir(char *dir)

{

    struct xs_dirs *d;



    d = g_malloc(sizeof(*d));

    d->xs_dir = dir;

    QTAILQ_INSERT_TAIL(&xs_cleanup, d, list);

}



void xen_config_cleanup(void)

{

    struct xs_dirs *d;



    QTAILQ_FOREACH(d, &xs_cleanup, list) {

	xs_rm(xenstore, 0, d->xs_dir);

    }

}



/* ------------------------------------------------------------- */



static int xen_config_dev_mkdir(char *dev, int p)

{

    struct xs_permissions perms[2] = {{

            .id    = 0, /* set owner: dom0 */

        },{

            .id    = xen_domid,

            .perms = p,

        }};



    if (!xs_mkdir(xenstore, 0, dev)) {

	xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", dev);

	return -1;

    }

    xen_config_cleanup_dir(g_strdup(dev));



    if (!xs_set_permissions(xenstore, 0, dev, perms, 2)) {

	xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", dev);

	return -1;

    }

    return 0;

}



static int xen_config_dev_dirs(const char *ftype, const char *btype, int vdev,

			       char *fe, char *be, int len)

{
@@ -66,8 +18,8 @@ static int xen_config_dev_dirs(const char *ftype, const char *btype, int vdev, 
    snprintf(be, len, "%s/backend/%s/%d/%d", dom, btype, xen_domid, vdev);

    free(dom);



    xen_config_dev_mkdir(fe, XS_PERM_READ | XS_PERM_WRITE);

    xen_config_dev_mkdir(be, XS_PERM_READ);

    xenstore_mkdir(fe, XS_PERM_READ | XS_PERM_WRITE);

    xenstore_mkdir(be, XS_PERM_READ);

    return 0;

}

include/hw/xen/xen_backend.h

+2 −0
Original line number Diff line number Diff line
@@ -28,6 +28,7 @@ struct XenDevOps { 
    int       (*free)(struct XenDevice *xendev);

    void      (*backend_changed)(struct XenDevice *xendev, const char *node);

    void      (*frontend_changed)(struct XenDevice *xendev, const char *node);

    int       (*backend_register)(void);

};



struct XenDevice {
@@ -63,6 +64,7 @@ extern const char *xen_protocol; 
extern DeviceState *xen_sysdev;



/* xenstore helper functions */

int xenstore_mkdir(char *path, int p);

int xenstore_write_str(const char *base, const char *node, const char *val);

int xenstore_write_int(const char *base, const char *node, int ival);

int xenstore_write_int64(const char *base, const char *node, int64_t ival);