From nobody Mon Feb 9 06:50:00 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) client-ip=192.237.175.120; envelope-from=xen-devel-bounces@lists.xenproject.org; helo=lists.xenproject.org; Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org ARC-Seal: i=1; a=rsa-sha256; t=1770255400; cv=none; d=zohomail.com; s=zohoarc; b=OvzoGCkqw6Szkv8VKUkIivCKtQfJhY/ayhiV49Wxaw9H4a9CGUytSJ60sh5zdkOdSg2sVxCXFe7XIBxTZDoZD0idOsmcAAghoUbdwNqCwcyeNH2OPi1gHQ8O/o2LIgJyoBx6VY6Cn4HKVKmJNo0wMJ5xsqALW719bQWava17L4A= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1770255400; h=Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=uMEQbYnd5xAAaBu981UD1vQcoXX8eKP0LOT3hk6YJ3Q=; b=PKLT9H1epOTohI+SuUR41wxVGddiggr75u8wlrEanZvIDurfGNJpxnPcxgnc37UujJLm6yJAP/jjG7fcncRmTvIgt0WZ+4A2Z1I2fCSuUepVxFUAyU43h1vGyKV1Qk/AAkQzPcA7SjF+r09/soEO0L4ips5bwxxtROm8kSWk3DQ= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of lists.xenproject.org designates 192.237.175.120 as permitted sender) smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Return-Path: Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) by mx.zohomail.com with SMTPS id 1770255400549970.7441198928673; Wed, 4 Feb 2026 17:36:40 -0800 (PST) Received: from list by lists.xenproject.org with outflank-mailman.1221354.1529648 (Exim 4.92) (envelope-from ) id 1vnoI9-0002d4-0b; Thu, 05 Feb 2026 01:36:21 +0000 Received: by outflank-mailman (output) from mailman id 1221354.1529648; Thu, 05 Feb 2026 01:36:20 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1vnoI8-0002ct-Sj; Thu, 05 Feb 2026 01:36:20 +0000 Received: by outflank-mailman (input) for mailman id 1221354; Thu, 05 Feb 2026 01:36:19 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1vnoI6-0002Qc-Ul for xen-devel@lists.xenproject.org; Thu, 05 Feb 2026 01:36:18 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.96) (envelope-from ) id 1vnoI6-003wQh-01; Thu, 05 Feb 2026 01:36:17 +0000 Received: from [140.209.201.102] (helo=localhost) by xenbits.xenproject.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1vnoI5-00HVXL-1b; Thu, 05 Feb 2026 01:36:17 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version 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" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:MIME-Version:References: In-Reply-To:Message-ID:Date:Subject:Cc:To:From; bh=uMEQbYnd5xAAaBu981UD1vQcoXX8eKP0LOT3hk6YJ3Q=; b=mam4JDzfk/p6OWqgGA5SomxTJ1 kfYr2LSIJttLdq4REByJY0418pIva21EdHEZQIO78b3QA0GPewW29bZ0QHloo0DXgouG4vk2mrXcv mviqLNow7s48GtjqYemVl4uDFo1wfUx6XF4hlmHTfx54LHwxzj9LP/4Aocal7ROGpHfk=; From: dmukhin@xen.org To: xen-devel@lists.xenproject.org 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 v5 4/6] xen/console: use memcpy() in console_init_ring() Date: Wed, 4 Feb 2026 17:36:04 -0800 Message-ID: <20260205013606.3384798-5-dmukhin@ford.com> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260205013606.3384798-1-dmukhin@ford.com> References: <20260205013606.3384798-1-dmukhin@ford.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ZohoMail-DKIM: pass (identity @xen.org) X-ZM-MESSAGEID: 1770255402433154100 Content-Type: text/plain; charset="utf-8" From: Denis Mukhin =20 Make console_init_ring() more efficient by using memcpy()'s, rather than copying the ring a byte at a time. Suggested-by: Andrew Cooper Signed-off-by: Denis Mukhin --- Changes since v4: - new patch --- xen/drivers/char/console.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/xen/drivers/char/console.c b/xen/drivers/char/console.c index ef9131439bba..3ad86fd436e2 100644 --- a/xen/drivers/char/console.c +++ b/xen/drivers/char/console.c @@ -463,7 +463,7 @@ static void cf_check conring_dump_keyhandler(unsigned c= har key) void __init console_init_ring(void) { char *ring; - unsigned int i, order, memflags; + unsigned int start, size, chunk, order, memflags; unsigned long flags; =20 if ( !opt_conring_size ) @@ -479,11 +479,23 @@ void __init console_init_ring(void) opt_conring_size =3D PAGE_SIZE << order; =20 nrspin_lock_irqsave(&console_lock, flags); - for ( i =3D conringc ; i !=3D conringp; i++ ) - ring[i & (opt_conring_size - 1)] =3D conring[i & (conring_size - 1= )]; + + start =3D conringc & (conring_size - 1); + size =3D min(conringp - conringc, conring_size); + chunk =3D min(size, conring_size - start); + + memcpy(&ring[0], &conring[start], chunk); + if ( size > chunk ) + memcpy(&ring[chunk], &conring[0], size - chunk); + + /* Data is moved to [0..size), re-position conring pointers. */ + conringc =3D 0; + conringp =3D size; + conring =3D ring; smp_wmb(); /* Allow users of console_force_unlock() to see larger buff= er. */ conring_size =3D opt_conring_size; + nrspin_unlock_irqrestore(&console_lock, flags); =20 printk("Allocated console ring of %u KiB.\n", opt_conring_size >> 10); --=20 2.52.0