>>> On 03.11.18 at 00:45, <sstabell...@kernel.org> wrote:
> Today Ctrl-AAA is used to switch between Xen and Dom0. Extend the
> mechanism to allow for switching between Xen, Dom0, and any of the
> initial DomU created from Xen alongside Dom0 out of information provided
> via device tree.
>
> Rename xen_rx to console_rx to match the new behavior.
>
> Clarify existing comment about "notify the guest", making it clear that
> it is only about the hardware domain.
>
> Switching the console input to domUs started from Xen at boot is
> #ifdef'ed to 0 in this patch. The code will be enabled when
> vpl011_rx_char_xen is introduced. For now it is disabled for
> bisectability.
>
> Signed-off-by: Stefano Stabellini <stefa...@xilinx.com>
Acked-by: Jan Beulich <jbeul...@suse.com>
with two remarks (but the ack applies with or without either
taken care of):
> @@ -391,31 +394,82 @@ static void dump_console_ring_key(unsigned char key)
> free_xenheap_pages(buf, order);
> }
>
> -/* CTRL-<switch_char> switches input direction between Xen and DOM0. */
> +/*
> + * CTRL-<switch_char> changes input direction, rotating among Xen, Dom0,
> + * and the DomUs started from Xen at boot.
> + */
> #define switch_code (opt_conswitch[0]-'a'+1)
> -static int __read_mostly xen_rx = 1; /* FALSE => input passed to domain 0. */
> +/*
> + * console_rx=0 => input to xen
> + * console_rx=1 => input to dom0
> + * console_rx=N => input to dom(N-1)
> + */
> +static unsigned int __read_mostly console_rx = 0;
>
> static void switch_serial_input(void)
> {
> - static char *input_str[2] = { "DOM0", "Xen" };
> - xen_rx = !xen_rx;
> - printk("*** Serial input -> %s", input_str[xen_rx]);
> + if ( console_rx == max_init_domid + 1 )
I generally consider it better to use >= in cases like this.
> static void __serial_rx(char c, struct cpu_user_regs *regs)
> {
> - if ( xen_rx )
> + switch ( console_rx )
> + {
> + case 0:
> return handle_keypress(c, regs);
>
> - /* Deliver input to guest buffer, unless it is already full. */
> - if ( (serial_rx_prod-serial_rx_cons) != SERIAL_RX_SIZE )
> - serial_rx_ring[SERIAL_RX_MASK(serial_rx_prod++)] = c;
> - /* Always notify the guest: prevents receive path from getting stuck. */
> - send_global_virq(VIRQ_CONSOLE);
> + case 1:
> + /*
> + * Deliver input to the hardware domain buffer, unless it is
> + * already full.
> + */
> + if ( (serial_rx_prod - serial_rx_cons) != SERIAL_RX_SIZE )
> + serial_rx_ring[SERIAL_RX_MASK(serial_rx_prod++)] = c;
> +
> + /*
> + * Always notify the hardware domain: prevents receive path from
> + * getting stuck.
> + */
> + send_global_virq(VIRQ_CONSOLE);
> + break;
> +
> +#if 0
> + default:
> + {
> + struct domain *d = rcu_lock_domain_by_any_id(console_rx - 1);
> +
> + /*
> + * If we have a properly initialized vpl011 console for the
> + * domain, without a full PV ring to Dom0 (in that case input
> + * comes from the PV ring), then send the character to it.
> + */
> + if ( d != NULL &&
> + !d->arch.vpl011.backend_in_domain &&
> + d->arch.vpl011.backend.xen != NULL )
> + vpl011_rx_char_xen(d, c);
> + else
> + printk("Cannot send chars to Dom%d: no UART available\n",
> + console_rx - 1);
> +
> + if ( d != NULL )
> + rcu_unlock_domain(d);
> + }
> +#endif
As said before, I would have preferred if this code block was
introduced only with the patch making it usable, rather than
with the #if 0 here.
Jan
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