On 26.07.2022 05:23, Marek Marczykowski-Górecki wrote:
> --- a/xen/drivers/char/Kconfig
> +++ b/xen/drivers/char/Kconfig
> @@ -85,6 +85,17 @@ config SERIAL_TX_BUFSIZE
>
> Default value is 16384 (16kiB).
>
> +config MAX_SERCONS
> + int "Maximum number of serial consoles active at once"
> + default 4
> + help
> + Controls how many serial consoles can be active at once. Configuring
> more
> + using `console=` parameter will be ignored.
> + When multiple consoles are configured, overhead of `sync_console`
> option
> + is even bigger.
> +
> + Default value is 4.
Indentation (the help text ought to be indented by a tab and two spaces).
> --- a/xen/drivers/char/console.c
> +++ b/xen/drivers/char/console.c
> @@ -113,7 +113,9 @@ static char *__read_mostly conring = _conring;
> static uint32_t __read_mostly conring_size = _CONRING_SIZE;
> static uint32_t conringc, conringp;
>
> -static int __read_mostly sercon_handle = -1;
> +#define MAX_SERCONS CONFIG_MAX_SERCONS
> +static int __read_mostly sercon_handle[MAX_SERCONS];
> +static int __read_mostly nr_sercon_handle = 0;
unsigned int please.
> @@ -393,32 +395,59 @@ long read_console_ring(struct xen_sysctl_readconsole
> *op)
> static char serial_rx_ring[SERIAL_RX_SIZE];
> static unsigned int serial_rx_cons, serial_rx_prod;
>
> -static void (*serial_steal_fn)(const char *, size_t nr) = early_puts;
> +/* The last entry means "steal from all consoles" */
> +static void (*serial_steal_fn[MAX_SERCONS+1])(const char *, size_t nr) = {
Nit: blanks please around + . But with ...
> + [MAX_SERCONS] = early_puts,
... this initializer you could as well omit the dimension.
> +};
>
> +/*
> + * Redirect console *handle* output to *fn*. Use SERHND_STEAL_ALL as
> *handle* to
> + * redirect all the consoles.
> + */
> int console_steal(int handle, void (*fn)(const char *, size_t nr))
> {
> - if ( (handle == -1) || (handle != sercon_handle) )
> - return 0;
> + int i;
While from the use inside the function this would better be unsigned int,
I can see how that would be slightly odd with the return value. But with
overly high a MAX_SERCONS ...
> + if ( handle == -1 )
> + return -ENOENT;
> + if ( serial_steal_fn[MAX_SERCONS] != NULL )
> + return -EBUSY;
> + if ( handle == SERHND_STEAL_ALL )
> + {
> + serial_steal_fn[MAX_SERCONS] = fn;
> + return MAX_SERCONS;
> + }
> + for ( i = 0; i < nr_sercon_handle; i++ )
> + if ( handle == sercon_handle[i] )
... the array access will degenerate when i is "int", but will be okay
when i is "unsigned int" (and of course everything will break if
MAX_SERCONS > UINT_MAX).
> + break;
> + if ( i == nr_sercon_handle )
> + return -ENOENT;
>
> - if ( serial_steal_fn != NULL )
> + if ( serial_steal_fn[i] != NULL )
> return -EBUSY;
>
> - serial_steal_fn = fn;
> - return 1;
> + serial_steal_fn[i] = fn;
> + return i;
> }
>
> void console_giveback(int id)
> {
> - if ( id == 1 )
> - serial_steal_fn = NULL;
> + if ( id >= 0 && id <= MAX_SERCONS )
> + serial_steal_fn[id] = NULL;
> }
>
> void console_serial_puts(const char *s, size_t nr)
> {
> - if ( serial_steal_fn != NULL )
> - serial_steal_fn(s, nr);
> + int i;
unsigned int please, again (yet more further down).
> + if ( serial_steal_fn[MAX_SERCONS] != NULL )
> + serial_steal_fn[MAX_SERCONS](s, nr);
> else
> - serial_puts(sercon_handle, s, nr);
> + for ( i = 0; i < nr_sercon_handle; i++ )
> + if ( serial_steal_fn[i] != NULL )
> + serial_steal_fn[i](s, nr);
> + else
> + serial_puts(sercon_handle[i], s, nr);
This for() would better gain braces.
> @@ -977,8 +1006,12 @@ void __init console_init_preirq(void)
> continue;
> else if ( (sh = serial_parse_handle(p)) >= 0 )
> {
> - sercon_handle = sh;
> - serial_steal_fn = NULL;
> + if ( nr_sercon_handle < MAX_SERCONS )
> + sercon_handle[nr_sercon_handle++] = sh;
> + else
> + printk("Too many consoles (max %d), ignoring '%s'\n",
> + MAX_SERCONS, p);
In order to use p here, I think we want (need?) to make
serial_parse_handle()'s parameter const char *.
> --- a/xen/drivers/char/xhci-dbc.c
> +++ b/xen/drivers/char/xhci-dbc.c
> @@ -1078,8 +1078,12 @@ void __init xhci_dbc_uart_init(void)
>
> e = parse_pci(opt_dbgp + 8, NULL, &bus, &slot, &func);
> if ( !e || *e )
> + {
> + printk(XENLOG_ERR
> + "Invalid dbgp= PCI device spec: '%s'\n",
> + opt_dbgp);
> return;
> -
> + }
> dbc->sbdf = PCI_SBDF(0, bus, slot, func);
> }
Does this change belong elsewhere?
Jan
