From nobody Sat Nov 15 17:07:32 2025 Delivered-To: importer@patchew.org Authentication-Results: mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass(p=quarantine dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1749666631; cv=none; d=zohomail.com; s=zohoarc; b=koUMRUPsBFqwwGh88YKi19yNh/MivpkQzOP0YVZNLk3QMUWYSaEBg/RFx1X4hRCVAf55jPAFPq1Hy6ECuJtmxnujVzvHXkdxMTWB0Cw3NkHh6NvKb4tRrRD3qCG9znm/LYpA1mDaD5QU2NMXbnjB9V2/EaZP2IzoGdWYD/HNkME= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1749666631; h=Content-Type:Content-Transfer-Encoding:Cc:Cc:Date:Date:From:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:Subject:To:To:Message-Id:Reply-To; bh=M9LZ45V6NuLQ3B6KycXNWkn9735EaN4kZUBKCu+5+Lc=; b=Bj3iWmSWMOqOLTWmAKN2aQ6/LWal94lgIcALvUZFSZE4HKzuZZcUzihgwP+518VRhRzD+rqLJ+gwUtCw5tMKYUW4pT2x/Gpby5lT0dB+/yjBiWnenwg8QqqVUUF/HSxOKUwhwEou3XEZ+9j3sMUhZceWj5yUrhnW4kbQdL6EiA8= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=pass header.from= (p=quarantine dis=none) Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1749666631673778.5023132711416; Wed, 11 Jun 2025 11:30:31 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uPQDL-00081c-AM; Wed, 11 Jun 2025 14:30:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uPQAO-00022a-6e for qemu-devel@nongnu.org; Wed, 11 Jun 2025 14:27:21 -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 1uPQAJ-0001b1-Ne for qemu-devel@nongnu.org; Wed, 11 Jun 2025 14:27:15 -0400 Received: from mx-prod-mc-04.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-684-QbkNV5_QN22LFuGxiASsBw-1; Wed, 11 Jun 2025 14:27:00 -0400 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 62C4C19560B2; Wed, 11 Jun 2025 18:26:56 +0000 (UTC) Received: from localhost (unknown [10.2.16.122]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 746E130002C6; Wed, 11 Jun 2025 18:26:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749666424; 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=M9LZ45V6NuLQ3B6KycXNWkn9735EaN4kZUBKCu+5+Lc=; b=Cerm+UYTnrKy2sDtF0KN+wZUZcMkeLJt3qC0x0LXUoBs75pEe5KrPaerQry8ZxOrsl6Uxy 9CBnnmS64SL7wuhI8hokSa7bgYJbMHkzjiTzS9IwOPMbMtoEsp0jtgRoBrmDgDWp+G4QMd PeIveOrCMADPWAiHTpJvfjf7lhf7muo= X-MC-Unique: QbkNV5_QN22LFuGxiASsBw-1 X-Mimecast-MFC-AGG-ID: QbkNV5_QN22LFuGxiASsBw_1749666416 From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org, Daniel Henrique Barboza , qemu-block@nongnu.org, Jesper Devantier , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Peter Maydell , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Harsh Prateek Bora , Troy Lee , Paolo Bonzini , Hanna Reitz , qemu-s390x@nongnu.org, Halil Pasic , Kevin Wolf , "Michael S. Tsirkin" , qemu-trivial@nongnu.org, Dmitry Fleytman , Jason Wang , Keith Busch , Nicholas Piggin , =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20Barrat?= , Fam Zheng , Sven Schnelle , Stefan Hajnoczi , Joel Stanley , Gerd Hoffmann , "Edgar E. Iglesias" , qemu-arm@nongnu.org, Hannes Reinecke , Klaus Jensen , Jeuk Kim , Andrew Jeffery , Alistair Francis , Thomas Huth , Michael Tokarev , Laurent Vivier , Rob Herring , Steven Lee , Jamin Lin , Christian Borntraeger , =?UTF-8?q?C=C3=A9dric=20Le=20Goater?= , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= Subject: [PULL 19/31] hw/net/rtl8139: skip automatic zero-init of large array Date: Wed, 11 Jun 2025 14:25:21 -0400 Message-ID: <20250611182533.200590-20-stefanha@redhat.com> In-Reply-To: <20250611182533.200590-1-stefanha@redhat.com> References: <20250611182533.200590-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1749666632657116600 From: Daniel P. Berrang=C3=A9 The 'rtl8139_transmit_one' method has a 8k byte array used for copying data between guest and host. Skip the automatic zero-init of this array to eliminate the performance overhead in the I/O hot path. The 'txbuffer' will be fully initialized when reading PCI DMA buffers. Signed-off-by: Daniel P. Berrang=C3=A9 Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-20-berrange@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/net/rtl8139.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/net/rtl8139.c b/hw/net/rtl8139.c index 15b8f7501a..654a087d80 100644 --- a/hw/net/rtl8139.c +++ b/hw/net/rtl8139.c @@ -1816,7 +1816,7 @@ static int rtl8139_transmit_one(RTL8139State *s, int = descriptor) =20 PCIDevice *d =3D PCI_DEVICE(s); int txsize =3D s->TxStatus[descriptor] & 0x1fff; - uint8_t txbuffer[0x2000]; + QEMU_UNINITIALIZED uint8_t txbuffer[0x2000]; =20 DPRINTF("+++ transmit reading %d bytes from host memory at 0x%08x\n", txsize, s->TxAddr[descriptor]); --=20 2.49.0