[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [qemu-xen master] xen-bus: only set the xen device frontend state if it is missing
commit 933ebad2470a169504799a1d95b8e410bd9847ef Author: Mark Syms <mark.syms@xxxxxxxxxx> AuthorDate: Wed Sep 18 12:57:44 2019 +0100 Commit: Anthony PERARD <anthony.perard@xxxxxxxxxx> CommitDate: Fri Sep 27 11:21:35 2019 +0100 xen-bus: only set the xen device frontend state if it is missing Some toolstack implementations will set the frontend xenstore keys to Initialising which will then trigger the in guest PV drivers to begin initialising and some implementations will then set their state to Closing. If this has occurred then device realize must not overwrite the frontend keys as then the handshake will stall. Signed-off-by: Mark Syms <mark.syms@xxxxxxxxxx> Also avoid creating the frontend area if it already exists. Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx> Reviewed-by: Anthony PERARD <anthony.perard@xxxxxxxxxx> Message-Id: <20190918115745.39006-1-paul.durrant@xxxxxxxxxx> Signed-off-by: Anthony PERARD <anthony.perard@xxxxxxxxxx> (cherry picked from commit 6bd6b955c0b2666263700d39db153ab43c5e0c9e) --- hw/xen/xen-bus.c | 47 +++++++++++++++++++++++++++++++---------------- 1 file changed, 31 insertions(+), 16 deletions(-) diff --git a/hw/xen/xen-bus.c b/hw/xen/xen-bus.c index 32bbd2b541..63469e0cf9 100644 --- a/hw/xen/xen-bus.c +++ b/hw/xen/xen-bus.c @@ -857,6 +857,13 @@ static void xen_device_frontend_changed(void *opaque) } } +static bool xen_device_frontend_exists(XenDevice *xendev) +{ + enum xenbus_state state; + + return (xen_device_frontend_scanf(xendev, "state", "%u", &state) == 1); +} + static void xen_device_frontend_create(XenDevice *xendev, Error **errp) { XenBus *xenbus = XEN_BUS(qdev_get_parent_bus(DEVICE(xendev))); @@ -865,19 +872,25 @@ static void xen_device_frontend_create(XenDevice *xendev, Error **errp) xendev->frontend_path = xen_device_get_frontend_path(xendev); - perms[0].id = xendev->frontend_id; - perms[0].perms = XS_PERM_NONE; - perms[1].id = xenbus->backend_id; - perms[1].perms = XS_PERM_READ | XS_PERM_WRITE; + /* + * The frontend area may have already been created by a legacy + * toolstack. + */ + if (!xen_device_frontend_exists(xendev)) { + perms[0].id = xendev->frontend_id; + perms[0].perms = XS_PERM_NONE; + perms[1].id = xenbus->backend_id; + perms[1].perms = XS_PERM_READ | XS_PERM_WRITE; - g_assert(xenbus->xsh); + g_assert(xenbus->xsh); - xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms, - ARRAY_SIZE(perms), &local_err); - if (local_err) { - error_propagate_prepend(errp, local_err, - "failed to create frontend: "); - return; + xs_node_create(xenbus->xsh, XBT_NULL, xendev->frontend_path, perms, + ARRAY_SIZE(perms), &local_err); + if (local_err) { + error_propagate_prepend(errp, local_err, + "failed to create frontend: "); + return; + } } xendev->frontend_state_watch = @@ -1290,12 +1303,14 @@ static void xen_device_realize(DeviceState *dev, Error **errp) xen_device_backend_set_online(xendev, true); xen_device_backend_set_state(xendev, XenbusStateInitWait); - xen_device_frontend_printf(xendev, "backend", "%s", - xendev->backend_path); - xen_device_frontend_printf(xendev, "backend-id", "%u", - xenbus->backend_id); + if (!xen_device_frontend_exists(xendev)) { + xen_device_frontend_printf(xendev, "backend", "%s", + xendev->backend_path); + xen_device_frontend_printf(xendev, "backend-id", "%u", + xenbus->backend_id); - xen_device_frontend_set_state(xendev, XenbusStateInitialising, true); + xen_device_frontend_set_state(xendev, XenbusStateInitialising, true); + } xendev->exit.notify = xen_device_exit; qemu_add_exit_notifier(&xendev->exit); -- generated by git-patchbot for /home/xen/git/qemu-xen.git#master _______________________________________________ Xen-changelog mailing list Xen-changelog@xxxxxxxxxxxxxxxxxxxx https://lists.xenproject.org/xen-changelog
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