From patchwork Mon Mar 31 23:06:05 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Denis Mukhin X-Patchwork-Id: 14034201 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7FE27C3600C for ; Mon, 31 Mar 2025 23:10:51 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.933159.1335187 (Exim 4.92) (envelope-from ) id 1tzOHA-0007Te-Ss; Mon, 31 Mar 2025 23:10:40 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 933159.1335187; Mon, 31 Mar 2025 23:10:40 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tzOHA-0007TX-OX; Mon, 31 Mar 2025 23:10:40 +0000 Received: by outflank-mailman (input) for mailman id 933159; Mon, 31 Mar 2025 23:10:40 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1tzOCv-0003Id-9M for xen-devel@lists.xenproject.org; Mon, 31 Mar 2025 23:06:17 +0000 Received: from mail-10629.protonmail.ch (mail-10629.protonmail.ch [79.135.106.29]) by se1-gles-flk1.inumbo.com (Halon) with ESMTPS id bf3b71f5-0e84-11f0-9ffb-bf95429c2676; Tue, 01 Apr 2025 01:06:15 +0200 (CEST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: bf3b71f5-0e84-11f0-9ffb-bf95429c2676 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proton.me; s=protonmail; t=1743462374; x=1743721574; bh=nA0e2TwhrmernoJeWCrYjCUgWR7cF87XdlQEarMxjlo=; h=Date:To:From:Cc:Subject:Message-ID:In-Reply-To:References: Feedback-ID:From:To:Cc:Date:Subject:Reply-To:Feedback-ID: Message-ID:BIMI-Selector:List-Unsubscribe:List-Unsubscribe-Post; b=C6nqmLNoL0nngaACQE0eRKjc2s9vhF7zfdMbcxNdvETuI/R0oRSeLe64aXvCDwrD2 BgLS/D3PTGou0OmQiTiNy+IwITGqtVHncvV4+gAQlBk+ReMDJ4S0lKmKjjI19k5AuD IEKZ1VldXSX7+cI8WYC7ZQnB6Civpc+fDs0IgoOwCmWAgdcOK53FkEjNLkSLtea+TR pjPID1RgMXiTv5Mzd2bXewXe0IiLJylQ0rJ4EkiOA6gkc/zwnTeRZAsMvoqWGE3Br2 jW0/aLBr0HBMYjMyeW356e1i/9p7J66NTpdsMBDLXq+3+2LUSTZdqxq01IjNc3Lb2a MBRdli7mNQ4wg== Date: Mon, 31 Mar 2025 23:06:05 +0000 To: xen-devel@lists.xenproject.org From: dmkhn@proton.me Cc: andrew.cooper3@citrix.com, anthony.perard@vates.tech, jbeulich@suse.com, julien@xen.org, michal.orzel@amd.com, roger.pau@citrix.com, sstabellini@kernel.org, dmukhin@ford.com Subject: [PATCH v2 6/7] xen/console: introduce console_set_focus() Message-ID: <20250331230508.440198-7-dmukhin@ford.com> In-Reply-To: <20250331230508.440198-1-dmukhin@ford.com> References: <20250331230508.440198-1-dmukhin@ford.com> Feedback-ID: 123220910:user:proton X-Pm-Message-ID: 9cf4c79d70e4712c1505e0ff6c87326deab81cd4 MIME-Version: 1.0 From: Denis Mukhin Switch console_focus address space from integers mapped to domain IDs to direct domain IDs, simplifying the console input switching code. Introduce console_set_focus() to set the console owner domain identifier. Signed-off-by: Denis Mukhin --- Changes since v1: - update console_focus description --- xen/drivers/char/console.c | 88 ++++++++++++++++---------------------- 1 file changed, 37 insertions(+), 51 deletions(-) diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c index 42974c0af7..9905ffd6b9 100644 --- a/xen/drivers/char/console.c +++ b/xen/drivers/char/console.c @@ -462,17 +462,12 @@ static void cf_check dump_console_ring_key(unsigned char key) /* * CTRL- changes input direction, rotating among Xen, Dom0, - * and the DomUs started from Xen at boot. + * and the DomUs. */ #define switch_code (opt_conswitch[0]-'a'+1) -/* - * console_rx=0 => input to xen - * 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_focus = 0; -#define max_console_rx (domid_top() + 1) +/* Console owner domain identifier. */ +static domid_t __read_mostly console_focus = DOMID_XEN; static struct domain *console_get_domain_by_id(domid_t domid) { @@ -491,9 +486,7 @@ static struct domain *console_get_domain_by_id(domid_t domid) struct domain *console_get_domain(void) { - if ( console_focus == 0 ) - return NULL; - return console_get_domain_by_id(console_focus - 1); + return console_get_domain_by_id(console_focus); } void console_put_domain(struct domain *d) @@ -511,42 +504,43 @@ static bool console_is_input_allowed(domid_t domid) return !!d; } -static void console_switch_input(void) +/* + * Set owner of the physical console input. + */ +static bool cf_check console_set_focus(domid_t domid) { - unsigned int next_rx = console_focus; + if ( domid == DOMID_XEN ) + printk("*** Serial input to Xen"); + else if ( console_is_input_allowed(domid) ) + printk("*** Serial input to DOM%u", domid); + else + return false; - /* - * Rotate among Xen, dom0 and boot-time created domUs while skipping - * switching serial input to non existing domains. - */ - for ( ; ; ) - { - domid_t domid; - - if ( next_rx++ >= max_console_rx ) - { - console_focus = 0; - printk("*** Serial input to Xen"); - break; - } - - if ( consoled_is_enabled() && next_rx == 1 ) - domid = get_initial_domain_id(); - else - domid = next_rx - 1; - - if ( console_is_input_allowed(domid) ) - { - console_focus = next_rx; - printk("*** Serial input to DOM%u", domid); - break; - } - } + console_focus = domid; if ( switch_code ) printk(" (type 'CTRL-%c' three times to switch input)", opt_conswitch[0]); printk("\n"); + + return true; +} + +/* + * Switch console focus. + * Rotates input focus among Xen and domains with console input permission. + */ +static void console_switch_input(void) +{ + const domid_t n = domid_top() + 1; + domid_t i = ( console_focus == DOMID_XEN ) + ? get_initial_domain_id() : console_focus + 1; + + for ( ; i < n; i++ ) + if ( console_set_focus(i) ) + return; + + ASSERT(console_set_focus(DOMID_XEN)); } static void __serial_rx(char c) @@ -554,7 +548,7 @@ static void __serial_rx(char c) struct domain *d; int rc = 0; - if ( console_focus == 0 ) + if ( console_focus == DOMID_XEN ) return handle_keypress(c, false); d = console_get_domain(); @@ -1129,14 +1123,6 @@ void __init console_endboot(void) video_endboot(); - /* - * If user specifies so, we fool the switch routine to redirect input - * straight back to Xen. I use this convoluted method so we still print - * a useful 'how to switch' message. - */ - if ( opt_conswitch[1] == 'x' ) - console_focus = max_console_rx; - register_keyhandler('w', dump_console_ring_key, "synchronously dump console ring buffer (dmesg)", 0); register_irq_keyhandler('+', &do_inc_thresh, @@ -1146,8 +1132,8 @@ void __init console_endboot(void) register_irq_keyhandler('G', &do_toggle_guest, "toggle host/guest log level adjustment", 0); - /* Serial input is directed to DOM0 by default. */ - console_switch_input(); + if ( opt_conswitch[1] != 'x' ) + (void)console_set_focus(get_initial_domain_id()); } int __init console_has(const char *device)