From nobody Sat Nov 15 17:06:26 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=1749666643; cv=none; d=zohomail.com; s=zohoarc; b=bItX3EHrjQV00HdR9KEZiBjAPd6UsVL9wPWWfA0bX05nLyyZvQ90XO5Jwxwvc0vzq053NsrnTpHyha8o0Ug33W3w/SJ9Zb8IMfUjXrrT0QMKomJRi9qyaq81tErXk0Xdgwyr/oyY7ArpDEZNzL1Sz2Aa4NBt97p//P618U6/LU4= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1749666643; 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=98MBMcUSEptGVNIPVLyiue7Ww+HKRSay/z2TDY8nvFw=; b=Q4AK3C76tUokO9bXLcqxGNgacPzGSwW41tKqFkIUPIUrTqnAtyXuH8o7KQVqt+g/WVOcoD633C/vYSJqgAqAgJY/NgEgcvRU9l4ZCHW1ekzDR5YH9uZyt2aXoW1vn/43lP42ZmvXtqZfQtPECkcpm2NESQqbbLwRUjb/CVoI7a4= 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 17496666438211022.6726064413525; Wed, 11 Jun 2025 11:30:43 -0700 (PDT) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1uPQBK-0004Nz-Bm; Wed, 11 Jun 2025 14:28:14 -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 1uPQAJ-0001xl-Rx for qemu-devel@nongnu.org; Wed, 11 Jun 2025 14:27:13 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1uPQAA-0001ZH-Pr for qemu-devel@nongnu.org; Wed, 11 Jun 2025 14:27:08 -0400 Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-317-AELjrSb9N5yl-IVITRhf6w-1; Wed, 11 Jun 2025 14:26:56 -0400 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-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 76D7C18089B5; Wed, 11 Jun 2025 18:26:51 +0000 (UTC) Received: from localhost (unknown [10.2.16.122]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B00EF19560AF; Wed, 11 Jun 2025 18:26:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1749666421; 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=98MBMcUSEptGVNIPVLyiue7Ww+HKRSay/z2TDY8nvFw=; b=Xz2NS2lQhM0ooBA1AyawoB9y8KAO4xQNYB1976k5MK01UpfQ7hmu4jYuq86cM5FZitOK/+ imUXZyy0cNekwP7zLKcNqAWjXsT1+DuM3kceaFIa6+a1LgR7sjIYWhXIkghFlmEpwJscnm LBDRs1tqqK16Y5QxCCpoqutLM0pL6bk= X-MC-Unique: AELjrSb9N5yl-IVITRhf6w-1 X-Mimecast-MFC-AGG-ID: AELjrSb9N5yl-IVITRhf6w_1749666412 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 17/31] hw/hyperv/syndbg: skip automatic zero-init of large array Date: Wed, 11 Jun 2025 14:25:19 -0400 Message-ID: <20250611182533.200590-18-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 3.0 on 10.30.177.12 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=170.10.129.124; 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: 1749666646648116600 From: Daniel P. Berrang=C3=A9 The 'handle_recv_msg' method has a 4k byte array used for copying data between the network socket and guest memory. Skip the automatic zero-init of this array to eliminate the performance overhead in the I/O hot path. The 'data_buf' array will be fully initialized when data is read off the network socket. Signed-off-by: Daniel P. Berrang=C3=A9 Reviewed-by: Stefan Hajnoczi Message-id: 20250610123709.835102-18-berrange@redhat.com Signed-off-by: Stefan Hajnoczi --- hw/hyperv/syndbg.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/hw/hyperv/syndbg.c b/hw/hyperv/syndbg.c index 8b8a14750d..ac7e15f6f1 100644 --- a/hw/hyperv/syndbg.c +++ b/hw/hyperv/syndbg.c @@ -192,7 +192,7 @@ static uint16_t handle_recv_msg(HvSynDbg *syndbg, uint6= 4_t outgpa, { uint16_t ret; g_assert(MSG_BUFSZ >=3D qemu_target_page_size()); - uint8_t data_buf[MSG_BUFSZ]; + QEMU_UNINITIALIZED uint8_t data_buf[MSG_BUFSZ]; hwaddr out_len; void *out_data; ssize_t recv_byte_count; --=20 2.49.0