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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 6D086D591B2 for ; Mon, 18 Nov 2024 19:59:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1tD7st-0004fn-LY; Mon, 18 Nov 2024 14:58:07 -0500 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 1tD7sr-0004fd-K6 for qemu-devel@nongnu.org; Mon, 18 Nov 2024 14:58:05 -0500 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 1tD7sl-0005Mt-Qe for qemu-devel@nongnu.org; Mon, 18 Nov 2024 14:58:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1731959877; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=I+8+4wQtocpBqccWOBpFJbP0H/jKg+Q7O1ioCwGV6OU=; b=BboQ6Kjx7U8rInlgBjk05QtvIgCGIaPpZOoH8Frrn6Votu4aRkYxn+YXAQPXXuIVfiYff8 eqS04nIlwTLZgg3eUjl3BS8lyyNsT5j/CNjLEsEs44VpD/bTK5V19x2tupWPEgCZVvCJZe 9nOdu/kv6gJoMsQ2G7T2+C++W/lp8VQ= Received: from mx-prod-mc-01.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-191-hmYL05v7NuOFtIiVNGArNw-1; Mon, 18 Nov 2024 14:57:53 -0500 X-MC-Unique: hmYL05v7NuOFtIiVNGArNw-1 X-Mimecast-MFC-AGG-ID: hmYL05v7NuOFtIiVNGArNw Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B65B71955BD2; Mon, 18 Nov 2024 19:57:49 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.133]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 148CF1955F49; Mon, 18 Nov 2024 19:57:47 +0000 (UTC) Date: Mon, 18 Nov 2024 19:57:44 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Song Gao Cc: qemu-devel@nongnu.org, peter.maydell@linaro.org, "Jason A. Donenfeld" Subject: Re: [PULL 6/7] hw/loongarch: virt: pass random seed to fdt Message-ID: References: <20240912125132.268802-1-gaosong@loongson.cn> <20240912125132.268802-7-gaosong@loongson.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20240912125132.268802-7-gaosong@loongson.cn> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.142, 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, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Hi Song / Jason, We're seeing non-deterministic hangs in our functional test suite 'tests/functional/test_loongarch64_virt.py' and my attempt at git bisect is blaming this commit. With this applied, perhaps 1 time in 10, the test case hangs, with zero serial port output from EDK2 emitted https://gitlab.com/qemu-project/qemu/-/issues/2686 I'm not seeing an obvious flaw in this commit's code, so I'm wondering if it has accidentally tickled some other subtle pre-existing bug elsewhere. Some general problem with FDT handling on loongarch64 perhaps ? On Thu, Sep 12, 2024 at 08:51:31PM +0800, Song Gao wrote: > From: "Jason A. Donenfeld" > > If the FDT contains /chosen/rng-seed, then the Linux RNG will use it to > initialize early. Set this using the usual guest random number > generation function. > > This is the same procedure that's done in b91b6b5a2c ("hw/microblaze: > pass random seed to fdt"), e4b4f0b71c ("hw/riscv: virt: pass random seed > to fdt"), c6fe3e6b4c ("hw/openrisc: virt: pass random seed to fdt"), > 67f7e426e5 ("hw/i386: pass RNG seed via setup_data entry"), c287941a4d > ("hw/rx: pass random seed to fdt"), 5e19cc68fb ("hw/mips: boston: pass > random seed to fdt"), 6b23a67916 ("hw/nios2: virt: pass random seed to fdt") > c4b075318e ("hw/ppc: pass random seed to fdt"), and 5242876f37 > ("hw/arm/virt: dt: add rng-seed property"). > > These earlier commits later were amended to rerandomize the RNG seed on > snapshot load, but the LoongArch code somehow already does that, despite > not having this patch here, presumably due to some lucky copy and > pasting. > > Signed-off-by: Jason A. Donenfeld > Reviewed-by: Song Gao > Message-Id: <20240905153316.2038769-1-Jason@zx2c4.com> > Signed-off-by: Song Gao > --- > hw/loongarch/virt.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/hw/loongarch/virt.c b/hw/loongarch/virt.c > index 76dd29a391..81b1f9486f 100644 > --- a/hw/loongarch/virt.c > +++ b/hw/loongarch/virt.c > @@ -48,6 +48,7 @@ > #include "hw/block/flash.h" > #include "hw/virtio/virtio-iommu.h" > #include "qemu/error-report.h" > +#include "qemu/guest-random.h" > > static bool virt_is_veiointc_enabled(LoongArchVirtMachineState *lvms) > { > @@ -303,6 +304,7 @@ static void fdt_add_uart_node(LoongArchVirtMachineState *lvms, > static void create_fdt(LoongArchVirtMachineState *lvms) > { > MachineState *ms = MACHINE(lvms); > + uint8_t rng_seed[32]; > > ms->fdt = create_device_tree(&lvms->fdt_size); > if (!ms->fdt) { > @@ -316,6 +318,10 @@ static void create_fdt(LoongArchVirtMachineState *lvms) > qemu_fdt_setprop_cell(ms->fdt, "/", "#address-cells", 0x2); > qemu_fdt_setprop_cell(ms->fdt, "/", "#size-cells", 0x2); > qemu_fdt_add_subnode(ms->fdt, "/chosen"); > + > + /* Pass seed to RNG */ > + qemu_guest_getrandom_nofail(rng_seed, sizeof(rng_seed)); > + qemu_fdt_setprop(ms->fdt, "/chosen", "rng-seed", rng_seed, sizeof(rng_seed)); > } > > static void fdt_add_cpu_nodes(const LoongArchVirtMachineState *lvms) > -- > 2.34.1 > > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|