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 1F6CCC43334 for ; Tue, 5 Jul 2022 09:53:12 +0000 (UTC) Received: from localhost ([::1]:43934 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o8fF1-0001aS-7q for qemu-devel@archiver.kernel.org; Tue, 05 Jul 2022 05:53:11 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:55252) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o8fDj-0008Ta-UH; Tue, 05 Jul 2022 05:51:51 -0400 Received: from mail-vs1-xe34.google.com ([2607:f8b0:4864:20::e34]:44817) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1o8fDi-0007ei-5Y; Tue, 05 Jul 2022 05:51:51 -0400 Received: by mail-vs1-xe34.google.com with SMTP id h7so11296234vsr.11; Tue, 05 Jul 2022 02:51:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=message-id:date:mime-version:user-agent:subject:content-language:to :cc:references:from:in-reply-to:content-transfer-encoding; bh=g+M3NCUC2bx9WVSMBweHGZXOzVZqpwINudJfJNRFJRw=; b=CsSrVV19czuZBbc4ifWghzDy8VYfu/nooidj8ncGEgFVZGjit950UK1BpT5r1iPFxk /ShQdnkiSbz+hMxeSvQMIY5OXchypYZm/JgHmSHYv63l/drar7CisD4FEcODwNYxLKCs +Y2prM80bnU4ynJMuM0YSAMqYqgM/RB3sVgDTUP3kY4H18MNOKjQCCl2WMU54CVQDDI6 LyBPcDNZzmjnJXPzQbl8YqTIRVQV6npXwaO1S3zl1mbDwriq10G2j3jSrlU9mG2wONhJ k7EsyRk3ymHcA1nasM9XN4k7FmR1q5q4lO4MDN2aMIfcV83Gg6QWfi813rzDXG/nUi+T 8+dA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=g+M3NCUC2bx9WVSMBweHGZXOzVZqpwINudJfJNRFJRw=; b=ziSohGgG0REwYkwQujevt0PrTHgt7Ub0mFl/qZmxHwSPh6qP8avTpPQl1wPi0Cu2ms s5XLvaTNN5ZXYRl2vmQQgwR2l6GdaxtOFfseJ53EWBOoLdb/sOhF7CGQlEbmVgLReIEU z+ZV7nL0HU0V/wnjAs4jC0XQfJ3ZvLoj6b5TmuoL4btPcjy3NU+/OWcmiocwlr34p8ZO FKfZNzs0iDqIXMCg9lxmti9WqaYdA7WE07PVX4c1UL68NpwuH675urKj0zH78yVEOzM+ 2RheEEYtjU1N4DdhJaZ3/obsP9NMLNKuG4cGMNoRD7999fxwX/oOtGtaIt8o5wB0FoYG WQEQ== X-Gm-Message-State: AJIora9H8LD8EpjiTUrzRzTkvXvqtycoRgPGnOuwDGt6IoKiCM/bpR2V XDWBM136JkbcCrUpPJR5hJc= X-Google-Smtp-Source: AGRyM1vactXb2ttlONw0WU4mnfvyLWd/gM2M97OE6aopKozR3kxBcB8IGRTDMd4WtiFHdAZvdoqrcA== X-Received: by 2002:a05:6102:f11:b0:356:fd6c:1334 with SMTP id v17-20020a0561020f1100b00356fd6c1334mr550369vss.60.1657014706948; Tue, 05 Jul 2022 02:51:46 -0700 (PDT) Received: from [192.168.10.102] ([191.193.1.105]) by smtp.gmail.com with ESMTPSA id d73-20020a1f1d4c000000b0036cf73a1e99sm5817311vkd.39.2022.07.05.02.51.45 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Jul 2022 02:51:46 -0700 (PDT) Message-ID: <1b8bf728-aaac-9e44-a40c-f504768713dd@gmail.com> Date: Tue, 5 Jul 2022 06:51:44 -0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH 2/9] target/ppc: add errp to kvmppc_read_int_cpu_dt() Content-Language: en-US To: Mark Cave-Ayland , =?UTF-8?Q?C=c3=a9dric_Le_Goater?= , qemu-devel@nongnu.org Cc: qemu-ppc@nongnu.org References: <20220630194249.886747-1-danielhb413@gmail.com> <20220630194249.886747-3-danielhb413@gmail.com> <55014e2a-a668-4843-8338-850abeb5ff04@kaod.org> <47277f4f-a6a5-85dc-4806-67df8e2fc153@gmail.com> <6d37b1dc-5dfb-2513-f74e-3f58e84e8117@kaod.org> <1d2cd44f-fd61-4693-ecc0-f71c80131005@ilande.co.uk> <38468531-5eb0-a421-f90f-2a3c67222d40@gmail.com> <14dfc11a-bd4c-5d80-4e18-3153a6dced77@ilande.co.uk> From: Daniel Henrique Barboza In-Reply-To: <14dfc11a-bd4c-5d80-4e18-3153a6dced77@ilande.co.uk> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::e34; envelope-from=danielhb413@gmail.com; helo=mail-vs1-xe34.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 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, FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_NONE=-0.0001, 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 7/5/22 06:44, Mark Cave-Ayland wrote: > On 05/07/2022 10:39, Daniel Henrique Barboza wrote: > >> On 7/5/22 03:51, Mark Cave-Ayland wrote: >>> On 04/07/2022 18:34, Cédric Le Goater wrote: >>> >>>> On 7/2/22 15:34, Daniel Henrique Barboza wrote: >>>>> >>>>> >>>>> On 7/2/22 03:24, Cédric Le Goater wrote: >>>>>> On 6/30/22 21:42, Daniel Henrique Barboza wrote: >>>>>>> The function can't just return 0 whether an error happened and call it a >>>>>>> day. We must provide a way of letting callers know if the zero return is >>>>>>> legitimate or due to an error. >>>>>>> >>>>>>> Add an Error pointer to kvmppc_read_int_cpu_dt() that will be filled >>>>>>> with an appropriate error, if one occurs. Callers are then free to pass >>>>>>> an Error pointer and handle it. >>>>>>> >>>>>>> Signed-off-by: Daniel Henrique Barboza >>>>>>> --- >>>>>>>   target/ppc/kvm.c | 16 +++++++++------- >>>>>>>   1 file changed, 9 insertions(+), 7 deletions(-) >>>>>>> >>>>>>> diff --git a/target/ppc/kvm.c b/target/ppc/kvm.c >>>>>>> index 109823136d..bc17437097 100644 >>>>>>> --- a/target/ppc/kvm.c >>>>>>> +++ b/target/ppc/kvm.c >>>>>>> @@ -1925,15 +1925,17 @@ static uint64_t kvmppc_read_int_dt(const char *filename) >>>>>>>   /* >>>>>>>    * Read a CPU node property from the host device tree that's a single >>>>>>> - * integer (32-bit or 64-bit).  Returns 0 if anything goes wrong >>>>>>> - * (can't find or open the property, or doesn't understand the format) >>>>>>> + * integer (32-bit or 64-bit).  Returns 0 and set errp if anything goes >>>>>>> + * wrong (can't find or open the property, or doesn't understand the >>>>>>> + * format) >>>>>>>    */ >>>>>>> -static uint64_t kvmppc_read_int_cpu_dt(const char *propname) >>>>>>> +static uint64_t kvmppc_read_int_cpu_dt(const char *propname, Error **errp) >>>>>>>   { >>>>>>>       char buf[PATH_MAX], *tmp; >>>>>>>       uint64_t val; >>>>>>>       if (kvmppc_find_cpu_dt(buf, sizeof(buf))) { >>>>>>> +        error_setg(errp, "Failed to read CPU property %s", propname); >>>>>>>           return 0; >>>>>>>       } >>>>>>> @@ -1946,12 +1948,12 @@ static uint64_t kvmppc_read_int_cpu_dt(const char *propname) >>>>>>>   uint64_t kvmppc_get_clockfreq(void) >>>>>>>   { >>>>>>> -    return kvmppc_read_int_cpu_dt("clock-frequency"); >>>>>>> +    return kvmppc_read_int_cpu_dt("clock-frequency", NULL); >>>>>> >>>>>> >>>>>> This should be fatal. no ? >>>>> >>>>> >>>>> I'm not sure. I went under the assumption that there might be some weird >>>>> condition where 'clock-frequency' might be missing from the DT, and this >>>>> is why we're not exiting out immediately. >>>>> >>>>> That said, the advantage of turning this into fatal is that we won't need >>>>> all the other patches that handles error on this function. We're going to >>>>> assume that if 'clock-frequency' is missing then we can't boot. I'm okay >>>>> with that. >>>> >>>> I think so. Some machines behave badly when 'clock-frequency' is bogus, >>>> division by zero, no console, etc. We could check easily with pseries >>>> which is the only KVM PPC platform. >>> >>> Well not quite true ;)  I haven't tested it during the last release cycle, but the Mac machines were still working fine to boot OS X with KVM-PR on my G4 Mac Mini last time I checked. >> >> >> We can't just error_fatal by default then. >> >> Each machine should be able to determine how to handle this missing DT >> element. If I want to error_fatal for pseries then I can do so in patch >> 9/9, but other than that I'll keep the existing behavior. > > This wouldn't be a problem for the Mac machines since they pass the clock frequency from QEMU to OpenBIOS using the fw_cfg interface which builds the tree itself rather than using FDT. So I think using error_fatal should still be fine. One less board that would break if we error_fatal in that condition then :) In theory, for boards that doesn't care/doesn't support KVM, this function shouldn't be even called. I guess I'll move the series into this direction instead. Daniel > > > ATB, > > Mark.