From: Manuel Bouyer <bou...@antioche.eu.org> The use of rcu_lock_domain_by_id() right in switch_serial_input() makes assumptions about domain IDs which don't hold when in shim mode: The sole (initial) domain there has a non-zero ID. Obtain the real domain ID in that case (generalized as get_initial_domain_id() returns zero when not in shim mode).
Note that console_input_domain() isn't altered, for not being used when in shim mode (or more generally on x86). Fixes: c2581c58bec9 ("xen/console: skip switching serial input to non existing domains") Signed-off-by: Manuel Bouyer <bou...@antioche.eu.org> Signed-off-by: Jan Beulich <jbeul...@suse.com> --- a/xen/drivers/char/console.c +++ b/xen/drivers/char/console.c @@ -468,7 +468,7 @@ static void cf_check dump_console_ring_k #define switch_code (opt_conswitch[0]-'a'+1) /* * console_rx=0 => input to xen - * console_rx=1 => input to dom0 + * console_rx=1 => input to dom0 (or the sole shim domain) * console_rx=N => input to dom(N-1) */ static unsigned int __read_mostly console_rx = 0; @@ -493,6 +493,7 @@ static void switch_serial_input(void) */ for ( ; ; ) { + domid_t domid; struct domain *d; if ( next_rx++ >= max_console_rx ) @@ -502,12 +503,18 @@ static void switch_serial_input(void) break; } - d = rcu_lock_domain_by_id(next_rx - 1); +#ifdef CONFIG_PV_SHIM + if ( next_rx == 1 ) + domid = get_initial_domain_id(); + else +#endif + domid = next_rx - 1; + d = rcu_lock_domain_by_id(domid); if ( d ) { rcu_unlock_domain(d); console_rx = next_rx; - printk("*** Serial input to DOM%u", next_rx - 1); + printk("*** Serial input to DOM%u", domid); break; } }