From patchwork Thu Apr 20 10:11:58 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Huth X-Patchwork-Id: 675615 Delivered-To: patch@linaro.org Received: by 2002:a5d:4a41:0:0:0:0:0 with SMTP id v1csp224458wrs; Thu, 20 Apr 2023 03:14:44 -0700 (PDT) X-Google-Smtp-Source: AKy350Z3AcNwWt/WQ4tivVqRcNKkTQorc+OX4c5hShU0Yuqj622FSwVGMb5EbiHUmSIiT2ODA0xR X-Received: by 2002:a05:6214:1c48:b0:5e0:7ecb:8ffa with SMTP id if8-20020a0562141c4800b005e07ecb8ffamr1081652qvb.1.1681985684434; Thu, 20 Apr 2023 03:14:44 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681985684; cv=none; d=google.com; s=arc-20160816; b=Mhv0BRSN4Dft2W2qckb+LDaSje4d3Jd6VO2A6W0hD5qPCFCTBEs8wohOXwvoyjFlKs Yi5+ePVpJbKMSVstsVL3ADHDhnAXvxFYZztVt7Qa57uJywHgggZW2tHAel44rNh2TeFG x+GGThNvHzWsAKdbX40Tz1Bmmv3AbaoXTb2jMk8hY4xrSMQEdql6ruiaYTGGNxVxPqTW EfmehfXNaeBGBu4kyp/RiKUG80oKSt8raXZs9MOW6kSbS5T+5TRg8x8vVBsH0PbeiReX k+9jeaeh0dYVliKlhuyzBbM4JuTaZ5MXJBblpLUUyC9h0PO3t2f8GgkxigFVWrVdRJXO wd/g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:content-transfer-encoding :mime-version:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=2QLrZjn/OknsMQll+23B6jfxbvFU3SjWJOMn7h956Ys=; b=Ss4ZB7Meawr4b6Ft5j52+bWfDcGga+MQKl214123A/hNF7QprtDeBRZOAwCnjKN93b dF6UBPwdQz8oMs9+RlWeidAH1Q+DhfdQLBb4i0USyvFr8wfav8l92+os08gclizNbB9t eEULlsgSfMkXhUfOU4LrrXVycANLkHovDubKojwKRfpAxiTev3X4nQHChu9SgM8FOVaq TbMs6HQmkljyqvieb4phjLyydAMxNO0GMl2XODlz/iE2k11s5kUKkC4Cfh1wAHuvmBKC 4M5jqK1hlbE+ueclKFakPqijeDOXSjRJywK9MnmZftghqPf9tthOPcwh6NvMDug8V2Cq OKHA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=CIshjdPP; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org. [209.51.188.17]) by mx.google.com with ESMTPS id m9-20020a0562141bc900b005ef58580b82si1053405qvc.115.2023.04.20.03.14.44 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 20 Apr 2023 03:14:44 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=CIshjdPP; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ppRHZ-0000ot-BU; Thu, 20 Apr 2023 06:12:53 -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 1ppRHP-0000cp-JO for qemu-devel@nongnu.org; Thu, 20 Apr 2023 06:12:43 -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 1ppRHE-0007zz-NW for qemu-devel@nongnu.org; Thu, 20 Apr 2023 06:12:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681985549; 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=2QLrZjn/OknsMQll+23B6jfxbvFU3SjWJOMn7h956Ys=; b=CIshjdPPD4JQjlUY8dlANi3HCq8lvbYhWAaDzkIQndj1AxrYLi6wkEX8U1dV5VYWwfL2JE S42d1H6cjdx93OlPqSqLA8V7IV9+WIqIFGq9Y8Up13mFwcO0td2p1YB0YyRGxO7f8NtP4c opwB3Scu3d8Ozee3CSNPRyS8IpoUT7A= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-241-yig7hIAZPbiTg-W80kWzkg-1; Thu, 20 Apr 2023 06:12:27 -0400 X-MC-Unique: yig7hIAZPbiTg-W80kWzkg-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 7774B85A588; Thu, 20 Apr 2023 10:12:27 +0000 (UTC) Received: from thuth.com (unknown [10.39.194.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id 87EA7440BC; Thu, 20 Apr 2023 10:12:26 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org Cc: Peter Maydell , Richard Henderson , =?utf-8?q?Marc-Andr=C3=A9?= =?utf-8?q?_Lureau?= Subject: [PULL 05/23] qtest: Don't assert on "-qtest chardev:myid" Date: Thu, 20 Apr 2023 12:11:58 +0200 Message-Id: <20230420101216.786304-6-thuth@redhat.com> In-Reply-To: <20230420101216.786304-1-thuth@redhat.com> References: <20230420101216.786304-1-thuth@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.129.124; envelope-from=thuth@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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org From: Peter Maydell If the -qtest command line argument is passed a string that says "use this chardev for I/O", then it will assert: $ ./build/clang/qemu-system-i386 -chardev file,path=/dev/null,id=myid -qtest chardev:myid Unexpected error in qtest_set_chardev() at ../../softmmu/qtest.c:1011: qemu-system-i386: Cannot find character device 'qtest' Aborted (core dumped) This is because in qtest_server_init() we assume that when we create the chardev with qemu_chr_new() it will always have the name "qtest". This is true if qemu_chr_new() had to create a new chardev, but not true if one already existed and is being referred to with "chardev:myid". Use the name of the chardev we get back from qemu_chr_new() as the string to set the qtest 'chardev' property to, instead of hardcoding it to "qtest". Signed-off-by: Peter Maydell Message-Id: <20230413150724.404304-2-peter.maydell@linaro.org> Reviewed-by: Marc-André Lureau Reviewed-by: Thomas Huth Signed-off-by: Thomas Huth --- softmmu/qtest.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/softmmu/qtest.c b/softmmu/qtest.c index 34bd2a33a7..26852996b5 100644 --- a/softmmu/qtest.c +++ b/softmmu/qtest.c @@ -867,7 +867,7 @@ void qtest_server_init(const char *qtest_chrdev, const char *qtest_log, Error ** } qtest = object_new(TYPE_QTEST); - object_property_set_str(qtest, "chardev", "qtest", &error_abort); + object_property_set_str(qtest, "chardev", chr->label, &error_abort); if (qtest_log) { object_property_set_str(qtest, "log", qtest_log, &error_abort); } From patchwork Thu Apr 20 10:11:59 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Thomas Huth X-Patchwork-Id: 675614 Delivered-To: patch@linaro.org Received: by 2002:a5d:4a41:0:0:0:0:0 with SMTP id v1csp224012wrs; Thu, 20 Apr 2023 03:13:42 -0700 (PDT) X-Google-Smtp-Source: AKy350YUkwF/NbvVjH+rMhQnDPfE5v/8ISLM520ooXwvDxgPz+EbtNwnPPP7dA7hyZKCM9xamdYV X-Received: by 2002:a05:622a:149:b0:3ef:42f7:6f with SMTP id v9-20020a05622a014900b003ef42f7006fmr2566765qtw.19.1681985622340; Thu, 20 Apr 2023 03:13:42 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1681985622; cv=none; d=google.com; s=arc-20160816; b=GQ0qPxbNaV9/RFVLtng4VL2tuyU/DpGqArzX6WSOEagZjUTuQETqLOofOdwNCBaxj+ 5ogIDNowtUHbvHu1Ba3NIyahMVbiapjkuksCTwEt+YGuG+pTqCZ/02L6gT/roiujN7uQ UeQHe4HR1vI/B1IInHC7Q0qq9B2QvofvpOy8SclZpQR+00D6gpm+FIzdti2Hm6w4syLi qyEMyA570gL8SUAS9Qsp6uMDTGUzdhKipmHORErT8pqaRZUqDXwMNinwQc9iTZXr23Jq 3hnm1RAtHpl4O69ItFVhLz2WD5o2eCH648NB249pI6KtbeaNdxcucs5ZsvblgpKnRNWE ND7g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=sender:errors-to:list-subscribe:list-help:list-post:list-archive :list-unsubscribe:list-id:precedence:content-transfer-encoding :mime-version:references:in-reply-to:message-id:date:subject:cc:to :from:dkim-signature; bh=eCqBRJcCY9i3GrrdVn/uo/h4OMts4OWbIQoJsVCbAe0=; b=lNuT9pYGYMy5NMOuD2XO035V8WK4xMd6B2RrpamAqUKZ5mxWFoZ9F1unmIIJylvtWn DJwYNAxhTm2v827og0SVU+KWLJKbxg0ubyLCp02bZWiNZGMWugzFGznfSr8Y/Y9Try5p Jv5h2mlHijvMu0IuIAAUCuhsDK1LIH/LjMNiBCU6ko3PDRnApZGqg2d7JXptjB9K9dpa vx8vGDHUuPfF2gfLib5XADZV2b1uyoZW8DtUiw4xYUxocrWi1jDYLZmqHjDT2BN4RhzR 3tD+6xGS5jk2sBKj3bpNeoonBTI/h+FMoMJmKRCo5emNdUICtJDbCblrPgcfjp+Nppj5 whMA== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Qb0GmH+P; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org. [209.51.188.17]) by mx.google.com with ESMTPS id d3-20020a05620a240300b007456fa51212si936746qkn.250.2023.04.20.03.13.42 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Thu, 20 Apr 2023 03:13:42 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=pass header.i=@redhat.com header.s=mimecast20190719 header.b=Qb0GmH+P; spf=pass (google.com: domain of qemu-devel-bounces+patch=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-devel-bounces+patch=linaro.org@nongnu.org"; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ppRHa-0000s4-9Z; Thu, 20 Apr 2023 06:12:54 -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 1ppRHP-0000e5-JO for qemu-devel@nongnu.org; Thu, 20 Apr 2023 06:12:43 -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 1ppRHF-00080J-K1 for qemu-devel@nongnu.org; Thu, 20 Apr 2023 06:12:36 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1681985552; 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=eCqBRJcCY9i3GrrdVn/uo/h4OMts4OWbIQoJsVCbAe0=; b=Qb0GmH+P1NSeVhFQT+ntwSJIBxvUfhPXzxiw3I4YDUgSaGtHdd6nbkajrxFFQVvQGT+/RO pp/cqWBRBJ70y3e0HM50pJLBJXbiwrtzfJbjr2CNTGUkvzBzc9/6EVn3qbMwmP7YAZrorn j2DhFEw5mOAwnd/FPj3rfI57PwQqAz0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-478--nnOqrTqO12eQiSO4NfDfw-1; Thu, 20 Apr 2023 06:12:29 -0400 X-MC-Unique: -nnOqrTqO12eQiSO4NfDfw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id BCBEF1C17423; Thu, 20 Apr 2023 10:12:28 +0000 (UTC) Received: from thuth.com (unknown [10.39.194.14]) by smtp.corp.redhat.com (Postfix) with ESMTP id BAE64440BC; Thu, 20 Apr 2023 10:12:27 +0000 (UTC) From: Thomas Huth To: qemu-devel@nongnu.org Cc: Peter Maydell , Richard Henderson , =?utf-8?q?Philippe_Mathie?= =?utf-8?q?u-Daud=C3=A9?= , =?utf-8?q?Marc-Andr=C3=A9_Lur?= =?utf-8?q?eau?= Subject: [PULL 06/23] chardev: Allow setting file chardev input file on the command line Date: Thu, 20 Apr 2023 12:11:59 +0200 Message-Id: <20230420101216.786304-7-thuth@redhat.com> In-Reply-To: <20230420101216.786304-1-thuth@redhat.com> References: <20230420101216.786304-1-thuth@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass client-ip=170.10.133.124; envelope-from=thuth@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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham 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+patch=linaro.org@nongnu.org Sender: qemu-devel-bounces+patch=linaro.org@nongnu.org From: Peter Maydell Our 'file' chardev backend supports both "output from this chardev is written to a file" and "input from this chardev should be read from a file" (except on Windows). However, you can only set up the input file if you're using the QMP interface -- there is no command line syntax to do it. Add command line syntax to allow specifying an input file as well as an output file, using a new 'input-path' suboption. The specific use case I have is that I'd like to be able to feed fuzzer reproducer input into qtest without having to use '-qtest stdio' and put the input onto stdin. Being able to use a file chardev like this: -chardev file,id=repro,path=/dev/null,input-path=repro.txt -qtest chardev:repro means that stdio is free for use by gdb. Signed-off-by: Peter Maydell Message-Id: <20230413150724.404304-3-peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Marc-André Lureau [thuth: Replace "input-file=" typo with "input-path="] Signed-off-by: Thomas Huth --- chardev/char-file.c | 8 ++++++++ chardev/char.c | 3 +++ qemu-options.hx | 10 ++++++++-- 3 files changed, 19 insertions(+), 2 deletions(-) diff --git a/chardev/char-file.c b/chardev/char-file.c index 3a7b9caf6f..263e6da563 100644 --- a/chardev/char-file.c +++ b/chardev/char-file.c @@ -100,6 +100,7 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, ChardevBackend *backend, Error **errp) { const char *path = qemu_opt_get(opts, "path"); + const char *inpath = qemu_opt_get(opts, "input-path"); ChardevFile *file; backend->type = CHARDEV_BACKEND_KIND_FILE; @@ -107,9 +108,16 @@ static void qemu_chr_parse_file_out(QemuOpts *opts, ChardevBackend *backend, error_setg(errp, "chardev: file: no filename given"); return; } +#ifdef _WIN32 + if (inpath) { + error_setg(errp, "chardev: file: input-path not supported on Windows"); + return; + } +#endif file = backend->u.file.data = g_new0(ChardevFile, 1); qemu_chr_parse_common(opts, qapi_ChardevFile_base(file)); file->out = g_strdup(path); + file->in = g_strdup(inpath); file->has_append = true; file->append = qemu_opt_get_bool(opts, "append", false); diff --git a/chardev/char.c b/chardev/char.c index e69390601f..661ad8176a 100644 --- a/chardev/char.c +++ b/chardev/char.c @@ -805,6 +805,9 @@ QemuOptsList qemu_chardev_opts = { },{ .name = "path", .type = QEMU_OPT_STRING, + },{ + .name = "input-path", + .type = QEMU_OPT_STRING, },{ .name = "host", .type = QEMU_OPT_STRING, diff --git a/qemu-options.hx b/qemu-options.hx index 59bdf67a2c..04c259157a 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -3360,7 +3360,7 @@ DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" - "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" + "-chardev file,id=id,path=path[,input-path=input-file][,mux=on|off][,logfile=PATH][,logappend=on|off]\n" "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" #ifdef _WIN32 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" @@ -3563,13 +3563,19 @@ The available backends are: Create a ring buffer with fixed size ``size``. size must be a power of two and defaults to ``64K``. -``-chardev file,id=id,path=path`` +``-chardev file,id=id,path=path[,input-path=input-path]`` Log all traffic received from the guest to a file. ``path`` specifies the path of the file to be opened. This file will be created if it does not already exist, and overwritten if it does. ``path`` is required. + If ``input-path`` is specified, this is the path of a second file + which will be used for input. If ``input-path`` is not specified, + no input will be available from the chardev. + + Note that ``input-path`` is not supported on Windows hosts. + ``-chardev pipe,id=id,path=path`` Create a two-way connection to the guest. The behaviour differs slightly between Windows hosts and other hosts: