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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9B419C433DF for ; Wed, 1 Jul 2020 17:10:37 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6725D206A1 for ; Wed, 1 Jul 2020 17:10:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="dtUFmpk0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6725D206A1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:46974 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqgFo-0003IV-N1 for qemu-devel@archiver.kernel.org; Wed, 01 Jul 2020 13:10:36 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55272) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqgFB-0002s3-Mf for qemu-devel@nongnu.org; Wed, 01 Jul 2020 13:09:57 -0400 Received: from mail-wm1-x343.google.com ([2a00:1450:4864:20::343]:37511) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jqgF9-0008Hx-9T for qemu-devel@nongnu.org; Wed, 01 Jul 2020 13:09:57 -0400 Received: by mail-wm1-x343.google.com with SMTP id o2so24039197wmh.2 for ; Wed, 01 Jul 2020 10:09:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=references:user-agent:from:to:cc:subject:in-reply-to:date :message-id:mime-version:content-transfer-encoding; bh=ZcsS3ZbExayhJN2YCVmmtE7bQcPjE7CPGpQkO/j5ARs=; b=dtUFmpk0eKODYMr3JGRG8GDtr7qp72YhhqvObNrCeWX3mYMRJPqopOOwULhlOSXIbm g350zsCJGwBIO7tJplcpiStgkI1B6pwTmmKfAIlOIye5HgX9VLd8d2EvECD5YyMhKddD udf7Ubii/Ybz8XLTEv64CD1ClNZ/GTqSgShCEZPnwMMktNB6z8IHbygY/BzMDzzX+RBQ 6rpyjtzyQY2uenumpuEhDGB05nsfNdIsyw1jiRlaVWJNB4peKkV/g0K4qRvhklC3jmJO QVWZXxbtcZ5rheyY2E7Xakvft/TvmGInn9vuXPj/VWebM+t+yuKGasjT5rd7zcIoVzM2 RFoQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:references:user-agent:from:to:cc:subject :in-reply-to:date:message-id:mime-version:content-transfer-encoding; bh=ZcsS3ZbExayhJN2YCVmmtE7bQcPjE7CPGpQkO/j5ARs=; b=O46G8jWSy9gI/QKQccFHmmHjAYHotXZ/FtLeTwVW4km2ic9Pb7iKnBBZpppcX0JbUF Le83itG4pDwg6g5u1HcmS08Q3H8sIehPZc0MdI4GwSBkH6/0J0SbV3laIEcaFiRqo+pO C5tGiOWytK82FS9UW/+WUWzXlC35SXis6gS8+tLFoG03lMklPDA7A4HC5MRfzeeYTVD1 RylVHHnCsZdBhRrfCMFOaZpfy5sr+I0vaSWF0iquEy5FAQFprzBRXMdQqs00L8mdQqij uwzvamTYuAHkg+2bNQnLQIDvG8GLbcy1qxjAGKoZBHDaA50Q8aqk3BwdLwxN6UACfedj YrpQ== X-Gm-Message-State: AOAM5328nrCiwearD86EDE287+iDTNdsd1ofsqfk28QhToVovc5CxV+m /UCm7RM+GyLr1gTaPEVkLzRPqw== X-Google-Smtp-Source: ABdhPJz+/fT3uzi+NtKmdNpmV1NhoRiOAxkhAHwakzDj3o9kZB8cJLxydfjWfByTTybkKAXS7UrqmQ== X-Received: by 2002:a7b:c18f:: with SMTP id y15mr28144202wmi.85.1593623392566; Wed, 01 Jul 2020 10:09:52 -0700 (PDT) Received: from zen.linaroharston ([51.148.130.216]) by smtp.gmail.com with ESMTPSA id b10sm7382244wmj.30.2020.07.01.10.09.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 01 Jul 2020 10:09:51 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 281D91FF7E; Wed, 1 Jul 2020 18:09:48 +0100 (BST) References: <20200701135652.1366-1-alex.bennee@linaro.org> <20200701135652.1366-2-alex.bennee@linaro.org> <85314d31-813a-8c20-7522-5186d5f31884@redhat.com> <87pn9fqjcd.fsf@linaro.org> <838d4d01-cd9e-d74a-5cd2-b23644172c9f@redhat.com> User-agent: mu4e 1.5.3; emacs 28.0.50 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v4 01/40] hw/isa: check for current_cpu before generating IRQ In-reply-to: <838d4d01-cd9e-d74a-5cd2-b23644172c9f@redhat.com> Date: Wed, 01 Jul 2020 18:09:48 +0100 Message-ID: <87k0znqi03.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=2a00:1450:4864:20::343; envelope-from=alex.bennee@linaro.org; helo=mail-wm1-x343.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. 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, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: fam@euphon.net, berrange@redhat.com, "Michael S. Tsirkin" , Bug 1878645 <1878645@bugs.launchpad.net>, richard.henderson@linaro.org, qemu-devel@nongnu.org, cota@braap.org, aurelien@aurel32.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Philippe Mathieu-Daud=C3=A9 writes: > On 7/1/20 6:40 PM, Alex Benn=C3=A9e wrote: >>=20 >> Philippe Mathieu-Daud=C3=A9 writes: >>=20 >>> On 7/1/20 3:56 PM, Alex Benn=C3=A9e wrote: >>>> It's possible to trigger this function from qtest/monitor at which >>>> point current_cpu won't point at the right place. Check it and >>>> fall back to first_cpu if it's NULL. >>>> >>>> Signed-off-by: Alex Benn=C3=A9e >>>> Cc: Bug 1878645 <1878645@bugs.launchpad.net> >>>> --- >>>> hw/isa/lpc_ich9.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c >>>> index cd6e169d47a..791c878eb0b 100644 >>>> --- a/hw/isa/lpc_ich9.c >>>> +++ b/hw/isa/lpc_ich9.c >>>> @@ -439,7 +439,7 @@ static void ich9_apm_ctrl_changed(uint32_t val, vo= id *arg) >>>> cpu_interrupt(cs, CPU_INTERRUPT_SMI); >>>> } >>>> } else { >>>> - cpu_interrupt(current_cpu, CPU_INTERRUPT_SMI); >>>> + cpu_interrupt(current_cpu ? current_cpu : first_cpu, CPU_= INTERRUPT_SMI); >>> >>> I'm not sure this change anything, as first_cpu is NULL when using >>> qtest accelerator or none-machine, see 508b4ecc39 ("gdbstub.c: fix >>> GDB connection segfault caused by empty machines"). >>=20 >> Good point - anyway feel free to ignore - it shouldn't have been in this >> series. It was just some random experimentation I was doing when looking >> at that bug. > > See commit c781a2cc42 ("hw/i386/vmport: Allow QTest use without > crashing") for a similar approach, but here I was thinking about > a more generic fix, not very intrusive: > > -- >8 -- > diff --git a/hw/isa/apm.c b/hw/isa/apm.c > index bce266b957..809afeb3e4 100644 > --- a/hw/isa/apm.c > +++ b/hw/isa/apm.c > @@ -40,7 +40,7 @@ static void apm_ioport_writeb(void *opaque, hwaddr > addr, uint64_t val, > if (addr =3D=3D 0) { > apm->apmc =3D val; > > - if (apm->callback) { > + if (apm->callback && !qtest_enabled()) { > (apm->callback)(val, apm->arg); > } But the other failure mode reported on the bug thread was via the monitor - so I'm not sure just checking for qtest catches that. > } else { > --- --=20 Alex Benn=C3=A9e 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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D78D9C433E0 for ; Wed, 1 Jul 2020 17:16:53 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id A974A20747 for ; Wed, 1 Jul 2020 17:16:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A974A20747 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bugs.launchpad.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:56574 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqgLs-0001Ii-Uv for qemu-devel@archiver.kernel.org; Wed, 01 Jul 2020 13:16:52 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56434) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqgKt-0000fI-KB for qemu-devel@nongnu.org; Wed, 01 Jul 2020 13:15:51 -0400 Received: from indium.canonical.com ([91.189.90.7]:60940) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jqgKr-0000o7-53 for qemu-devel@nongnu.org; Wed, 01 Jul 2020 13:15:51 -0400 Received: from loganberry.canonical.com ([91.189.90.37]) by indium.canonical.com with esmtp (Exim 4.86_2 #2 (Debian)) id 1jqgKn-0006hZ-JK for ; Wed, 01 Jul 2020 17:15:45 +0000 Received: from loganberry.canonical.com (localhost [127.0.0.1]) by loganberry.canonical.com (Postfix) with ESMTP id 316EE2E810C for ; Wed, 1 Jul 2020 17:15:45 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Date: Wed, 01 Jul 2020 17:09:48 -0000 From: =?utf-8?q?Alex_Benn=C3=A9e?= <1878645@bugs.launchpad.net> To: qemu-devel@nongnu.org X-Launchpad-Notification-Type: bug X-Launchpad-Bug: product=qemu; status=New; importance=Undecided; assignee=None; X-Launchpad-Bug-Information-Type: Public X-Launchpad-Bug-Private: no X-Launchpad-Bug-Security-Vulnerability: no X-Launchpad-Bug-Commenters: a1xndr ajbennee philmd X-Launchpad-Bug-Reporter: Alexander Bulekov (a1xndr) X-Launchpad-Bug-Modifier: =?utf-8?q?Alex_Benn=C3=A9e_=28ajbennee=29?= References: <158947246472.30762.752698283456022174.malonedeb@chaenomeles.canonical.com> <20200701135652.1366-2-alex.bennee@linaro.org> <85314d31-813a-8c20-7522-5186d5f31884@redhat.com> <87pn9fqjcd.fsf@linaro.org> <838d4d01-cd9e-d74a-5cd2-b23644172c9f@redhat.com> Message-ID: <87k0znqi03.fsf@linaro.org> Subject: [Bug 1878645] Re: [PATCH v4 01/40] hw/isa: check for current_cpu before generating IRQ X-Launchpad-Message-Rationale: Subscriber (QEMU) @qemu-devel-ml X-Launchpad-Message-For: qemu-devel-ml Precedence: bulk X-Generated-By: Launchpad (canonical.com); Revision="1cbd0aa39df153c901321817f9b57cf3f232b507"; Instance="production-secrets-lazr.conf" X-Launchpad-Hash: 600cf9813e7d5d84894a113652dbd1508f2400f0 Received-SPF: none client-ip=91.189.90.7; envelope-from=bounces@canonical.com; helo=indium.canonical.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/01 10:05:42 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -58 X-Spam_score: -5.9 X-Spam_bar: ----- X-Spam_report: (-5.9 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_NONE=0.001 autolearn=_AUTOLEARN X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Bug 1878645 <1878645@bugs.launchpad.net> Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20200701170948.ZlMtFKcvykjjNQisrIjMV3MtA4GNy6HvkoNGABF0Bgk@z> Philippe Mathieu-Daud=C3=A9 writes: > On 7/1/20 6:40 PM, Alex Benn=C3=A9e wrote: >> = >> Philippe Mathieu-Daud=C3=A9 writes: >> = >>> On 7/1/20 3:56 PM, Alex Benn=C3=A9e wrote: >>>> It's possible to trigger this function from qtest/monitor at which >>>> point current_cpu won't point at the right place. Check it and >>>> fall back to first_cpu if it's NULL. >>>> >>>> Signed-off-by: Alex Benn=C3=A9e >>>> Cc: Bug 1878645 <1878645@bugs.launchpad.net> >>>> --- >>>> hw/isa/lpc_ich9.c | 2 +- >>>> 1 file changed, 1 insertion(+), 1 deletion(-) >>>> >>>> diff --git a/hw/isa/lpc_ich9.c b/hw/isa/lpc_ich9.c >>>> index cd6e169d47a..791c878eb0b 100644 >>>> --- a/hw/isa/lpc_ich9.c >>>> +++ b/hw/isa/lpc_ich9.c >>>> @@ -439,7 +439,7 @@ static void ich9_apm_ctrl_changed(uint32_t val, vo= id *arg) >>>> cpu_interrupt(cs, CPU_INTERRUPT_SMI); >>>> } >>>> } else { >>>> - cpu_interrupt(current_cpu, CPU_INTERRUPT_SMI); >>>> + cpu_interrupt(current_cpu ? current_cpu : first_cpu, CPU_= INTERRUPT_SMI); >>> >>> I'm not sure this change anything, as first_cpu is NULL when using >>> qtest accelerator or none-machine, see 508b4ecc39 ("gdbstub.c: fix >>> GDB connection segfault caused by empty machines"). >> = >> Good point - anyway feel free to ignore - it shouldn't have been in this >> series. It was just some random experimentation I was doing when looking >> at that bug. > > See commit c781a2cc42 ("hw/i386/vmport: Allow QTest use without > crashing") for a similar approach, but here I was thinking about > a more generic fix, not very intrusive: > > -- >8 -- > diff --git a/hw/isa/apm.c b/hw/isa/apm.c > index bce266b957..809afeb3e4 100644 > --- a/hw/isa/apm.c > +++ b/hw/isa/apm.c > @@ -40,7 +40,7 @@ static void apm_ioport_writeb(void *opaque, hwaddr > addr, uint64_t val, > if (addr =3D=3D 0) { > apm->apmc =3D val; > > - if (apm->callback) { > + if (apm->callback && !qtest_enabled()) { > (apm->callback)(val, apm->arg); > } But the other failure mode reported on the bug thread was via the monitor - so I'm not sure just checking for qtest catches that. > } else { > --- -- = Alex Benn=C3=A9e -- = You received this bug notification because you are a member of qemu- devel-ml, which is subscribed to QEMU. https://bugs.launchpad.net/bugs/1878645 Title: null-ptr dereference in ich9_apm_ctrl_changed Status in QEMU: New Bug description: Hello, While fuzzing, I found an input which triggers a NULL pointer dereference= in tcg_handle_interrupt. It seems the culprint is a "cpu" pointer - maybe th= is bug is specific to QTest? =3D=3D23862=3D=3DERROR: AddressSanitizer: SEGV on unknown address 0x00000= 00000b4 (pc 0x55b9dc7c9dce bp 0x7ffc346a0900 sp 0x7ffc346a0880 T0) =3D=3D23862=3D=3DThe signal is caused by a READ memory access. =3D=3D23862=3D=3DHint: address points to the zero page. #0 0x55b9dc7c9dce in tcg_handle_interrupt /home/alxndr/Development/qe= mu/accel/tcg/tcg-all.c:57:21 #1 0x55b9dc904799 in cpu_interrupt /home/alxndr/Development/qemu/incl= ude/hw/core/cpu.h:872:5 #2 0x55b9dc9085e8 in ich9_apm_ctrl_changed /home/alxndr/Development/q= emu/hw/isa/lpc_ich9.c:442:13 #3 0x55b9dd19cdc8 in apm_ioport_writeb /home/alxndr/Development/qemu/= hw/isa/apm.c:50:13 #4 0x55b9dc73f8b4 in memory_region_write_accessor /home/alxndr/Develo= pment/qemu/memory.c:483:5 #5 0x55b9dc73f289 in access_with_adjusted_size /home/alxndr/Developme= nt/qemu/memory.c:544:18 #6 0x55b9dc73ddf5 in memory_region_dispatch_write /home/alxndr/Develo= pment/qemu/memory.c:1476:16 #7 0x55b9dc577bf3 in flatview_write_continue /home/alxndr/Development= /qemu/exec.c:3137:23 #8 0x55b9dc567ad8 in flatview_write /home/alxndr/Development/qemu/exe= c.c:3177:14 #9 0x55b9dc567608 in address_space_write /home/alxndr/Development/qem= u/exec.c:3268:18 #10 0x55b9dc723fe7 in cpu_outb /home/alxndr/Development/qemu/ioport.c= :60:5 #11 0x55b9dc72d3c0 in qtest_process_command /home/alxndr/Development/= qemu/qtest.c:392:13 #12 0x55b9dc72b186 in qtest_process_inbuf /home/alxndr/Development/qe= mu/qtest.c:710:9 #13 0x55b9dc72a8b3 in qtest_read /home/alxndr/Development/qemu/qtest.= c:722:5 #14 0x55b9ddc6e60b in qemu_chr_be_write_impl /home/alxndr/Development= /qemu/chardev/char.c:183:9 #15 0x55b9ddc6e75a in qemu_chr_be_write /home/alxndr/Development/qemu= /chardev/char.c:195:9 #16 0x55b9ddc77979 in fd_chr_read /home/alxndr/Development/qemu/chard= ev/char-fd.c:68:9 #17 0x55b9ddcff0e9 in qio_channel_fd_source_dispatch /home/alxndr/Dev= elopment/qemu/io/channel-watch.c:84:12 #18 0x7f7161eac897 in g_main_context_dispatch (/usr/lib/x86_64-linux-= gnu/libglib-2.0.so.0+0x4e897) #19 0x55b9ddebcb84 in glib_pollfds_poll /home/alxndr/Development/qemu= /util/main-loop.c:219:9 #20 0x55b9ddebb57d in os_host_main_loop_wait /home/alxndr/Development= /qemu/util/main-loop.c:242:5 #21 0x55b9ddebb176 in main_loop_wait /home/alxndr/Development/qemu/ut= il/main-loop.c:518:11 #22 0x55b9dcb4bd1d in qemu_main_loop /home/alxndr/Development/qemu/so= ftmmu/vl.c:1664:9 #23 0x55b9ddd1629c in main /home/alxndr/Development/qemu/softmmu/main= .c:49:5 #24 0x7f7160a5ce0a in __libc_start_main /build/glibc-GwnBeO/glibc-2.3= 0/csu/../csu/libc-start.c:308:16 #25 0x55b9dc49c819 in _start (/home/alxndr/Development/qemu/build/i38= 6-softmmu/qemu-system-i386+0xc9c819) = I can reproduce this in qemu 5.0 built with AddressSanitizer using these = qtest commands: cat << EOF | ./qemu-system-i386 \ -qtest stdio -nographic -monitor none -serial none \ -M pc-q35-5.0 outl 0xcf8 0x8400f841 outl 0xcfc 0xaa215d6d outl 0x6d30 0x2ef8ffbe outb 0xb2 0x20 EOF Please let me know if I can provide any further info. -Alex To manage notifications about this bug go to: https://bugs.launchpad.net/qemu/+bug/1878645/+subscriptions