From mboxrd@z Thu Jan 1 00:00:00 1970 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 lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (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 920FFC43458 for ; Tue, 7 Jul 2026 13:01:04 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wh5OE-0006KU-Jy; Tue, 07 Jul 2026 08:59:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wh5OD-0006I1-G2 for qemu-devel@nongnu.org; Tue, 07 Jul 2026 08:59:05 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wh5OB-0006gk-AW for qemu-devel@nongnu.org; Tue, 07 Jul 2026 08:59:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1783429142; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2FbkIW98jZ/SwSpR+1vhOb0Wiwd4C0+IxGrgo7niNvM=; b=QMtFYNujhWZ1BlrB0V1FXnrN+JLTRMV/bx8RLEzwr82CopuB2QsuPSINmNBkopY6eiQ4MM aqDwmcjIVv4RjJ2QMBs4LsW9IWXA90yvAzqZawQLaI787rC6M8CDNLAZm5d9xp3uYohfAK fSzv81QcB4tDgV65Awf1c+JBgiMsWVw= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-488-C34TqVcbMfqn-7r8Jlm_Tg-1; Tue, 07 Jul 2026 08:58:57 -0400 X-MC-Unique: C34TqVcbMfqn-7r8Jlm_Tg-1 X-Mimecast-MFC-AGG-ID: C34TqVcbMfqn-7r8Jlm_Tg_1783429135 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 7B31A1954198; Tue, 7 Jul 2026 12:58:55 +0000 (UTC) Received: from gondolin.fritz.box (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 8E7901956040; Tue, 7 Jul 2026 12:58:53 +0000 (UTC) From: Cornelia Huck To: qemu-devel@nongnu.org Cc: qemu-s390x@nongnu.org, Zhuoying Cai , Eric Farman , Jared Rossi , Matthew Rosato , Cornelia Huck Subject: [PULL 01/15] pc-bios/s390-ccw: Refactor byte swapping Date: Tue, 7 Jul 2026 14:58:33 +0200 Message-ID: <20260707125847.1785168-2-cohuck@redhat.com> In-Reply-To: <20260707125847.1785168-1-cohuck@redhat.com> References: <20260707125847.1785168-1-cohuck@redhat.com> MIME-Version: 1.0 Content-type: text/plain Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.133.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: 8 X-Spam_score: 0.8 X-Spam_bar: / X-Spam_report: (0.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.445, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_SBL_CSS=3.335, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org From: Zhuoying Cai Introduce local variables to cache the byte-swapped values eliminating some redundant byte swap operations. Additionally, do byte swap when polling to avoid a special case where endianness is preserved. Reviewed-by: Eric Farman Signed-off-by: Zhuoying Cai Signed-off-by: Jared Rossi Tested-by: Matthew Rosato Message-ID: <20260630141917.673995-2-jrossi@linux.ibm.com> Signed-off-by: Cornelia Huck --- pc-bios/s390-ccw/virtio.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/pc-bios/s390-ccw/virtio.c b/pc-bios/s390-ccw/virtio.c index 390b55c7b924..a448dc96e269 100644 --- a/pc-bios/s390-ccw/virtio.c +++ b/pc-bios/s390-ccw/virtio.c @@ -153,14 +153,14 @@ static void vr_bswap_descriptor(VRingDesc *desc) void vring_send_buf(VRing *vr, void *p, int len, int flags) { - if (!be_ipl()) { - vr->avail->idx = bswap16(vr->avail->idx); - } + uint16_t avail_idx; + + avail_idx = be_ipl() ? vr->avail->idx : bswap16(vr->avail->idx); /* For follow-up chains we need to keep the first entry point */ if (!(flags & VRING_HIDDEN_IS_CHAIN)) { - vr->avail->ring[vr->avail->idx % vr->num] = be_ipl() ? vr->next_idx : - bswap16(vr->next_idx); + vr->avail->ring[avail_idx % vr->num] = be_ipl() ? vr->next_idx : + bswap16(vr->next_idx); } vr->desc[vr->next_idx].addr = (unsigned long)p; @@ -177,23 +177,23 @@ void vring_send_buf(VRing *vr, void *p, int len, int flags) /* Chains only have a single ID */ if (!(flags & VRING_DESC_F_NEXT)) { - vr->avail->idx++; - } - - if (!be_ipl()) { - vr->avail->idx = bswap16(vr->avail->idx); + avail_idx++; + vr->avail->idx = be_ipl() ? avail_idx : bswap16(avail_idx); } } int vr_poll(VRing *vr) { - if (vr->used->idx == vr->used_idx) { + uint16_t used_idx; + + used_idx = be_ipl() ? vr->used->idx : bswap16(vr->used->idx); + if (used_idx == vr->used_idx) { vring_notify(vr); yield(); return 0; } - vr->used_idx = vr->used->idx; /* Endianness is preserved */ + vr->used_idx = used_idx; vr->next_idx = 0; vr->desc[0].len = 0; vr->desc[0].flags = 0; -- 2.54.0