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(p200300cbc70e9200ce93b5e68aa965d4.dip0.t-ipconnect.de. [2003:cb:c70e:9200:ce93:b5e6:8aa9:65d4]) by smtp.gmail.com with ESMTPSA id o10-20020a1c750a000000b003fe29dc0ff2sm1672547wmc.21.2023.08.25.02.13.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 25 Aug 2023 02:13:03 -0700 (PDT) Message-ID: Date: Fri, 25 Aug 2023 11:13:02 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id Content-Language: en-US To: Markus Armbruster Cc: ThinerLogoer , qemu-devel@nongnu.org, qemu-ppc@nongnu.org, Paolo Bonzini , Peter Xu , Igor Mammedov , =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= , =?UTF-8?Q?Daniel_P=2eBerrang=c3=a9?= , Stefan Hajnoczi , Elena Ufimtseva , Jagannathan Raman , "Michael S. Tsirkin" , Ani Sinha , Xiao Guangrong , Daniel Henrique Barboza , Greg Kurz , Eric Blake , Eduardo Habkost References: <20230823153412.832081-1-david@redhat.com> <20230823153412.832081-12-david@redhat.com> <209b4b8c.54bc.18a2b7b6f53.Coremail.logoerthiner1@163.com> <87msyfo5b0.fsf@pond.sub.org> From: David Hildenbrand Organization: Red Hat In-Reply-To: <87msyfo5b0.fsf@pond.sub.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=david@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -49 X-Spam_score: -5.0 X-Spam_bar: ----- X-Spam_report: (-5.0 / 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, NICE_REPLY_A=-2.919, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On 25.08.23 11:10, Markus Armbruster wrote: > David Hildenbrand writes: > >> On 25.08.23 08:57, ThinerLogoer wrote: >>> Hello, >>> >>> At 2023-08-23 23:34:11, "David Hildenbrand" wrote: >>>> For migration purposes, users might want to reuse the default RAM >>>> backend id, but specify a different memory backend. >>>> >>>> For example, to reuse "pc.ram" on q35, one has to set >>>> -machine q35,memory-backend=pc.ram >>>> Only then, can a memory backend with the id "pc.ram" be created >>>> manually. >>>> >>>> Let's improve the error message. >>>> >>>> Unfortuantely, we cannot use error_append_hint(), because the caller >>>> passes &error_fatal. >>>> >>>> Suggested-by: ThinerLogoer >>>> Signed-off-by: David Hildenbrand >>>> --- >>>> hw/core/machine.c | 4 +++- >>>> 1 file changed, 3 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/hw/core/machine.c b/hw/core/machine.c >>>> index f0d35c6401..dbcd124d45 100644 >>>> --- a/hw/core/machine.c >>>> +++ b/hw/core/machine.c >>>> @@ -1382,7 +1382,9 @@ void machine_run_board_init(MachineState *machine, const char *mem_path, Error * >>>> machine_class->default_ram_id)) { >>>> error_setg(errp, "object name '%s' is reserved for the default" >>>> " RAM backend, it can't be used for any other purposes." >>>> - " Change the object's 'id' to something else", >>>> + " Change the object's 'id' to something else or disable" >>>> + " automatic creation of the default RAM backend by setting" >>>> + " the 'memory-backend' machine property", >>>> machine_class->default_ram_id); >>>> return; >>>> } >>> >>> I'd suggest a more explicit version: >>> >>> " Change the object's 'id' to something else or disable" >>> " automatic creation of the default RAM backend by appending" >>> " 'memory-backend={machine_class->default_ram_id}' in '-machine' arguments", >> >> >> Thanks, I'll do: >> >> diff --git a/hw/core/machine.c b/hw/core/machine.c >> index f0d35c6401..cd0fd6cdd1 100644 >> --- a/hw/core/machine.c >> +++ b/hw/core/machine.c >> @@ -1382,8 +1382,10 @@ void machine_run_board_init(MachineState *machine, const char *mem_path, Error * >> machine_class->default_ram_id)) { >> error_setg(errp, "object name '%s' is reserved for the default" >> " RAM backend, it can't be used for any other purposes." >> - " Change the object's 'id' to something else", >> - machine_class->default_ram_id); >> + " Change the object's 'id' to something else or disable" >> + " automatic creation of the default RAM backend by appending" >> + " 'memory-backend=%s' in '-machine' arguments", >> + machine_class->default_ram_id, machine_class->default_ram_id); >> return; >> } >> if (!create_default_memdev(current_machine, mem_path, errp)) { > Hi Markus, > error_setg()'s function comment specifies: > > * The resulting message should be a single phrase, with no newline or > * trailing punctuation. > > Please use error_append_hint(), like so Please see the patch description: "Unfortunately, we cannot use error_append_hint(), because the caller passes &error_fatal." How should I deal with that? > > error_setg(errp, "object name '%s' is reserved for the default" > " RAM backend, it can't be used for any other purposes", > machine_class->default_ram_id); > error_append_hint(errp, > "Change the object's 'id' to something else or disable" > " automatic creation of the default RAM backend by appending" > " 'memory-backend=%s' in '-machine' arguments\n", > machine_class->default_ram_id); > > Moreover: > > * "object name" feels off, we're talking about IDs, aren't we? Yes, I think so. > > * "appending X in Y" should be "appending X to Y". Consider "setting > 'memory-backend=%s' with -machine". > Can do, thanks. -- Cheers, David / dhildenb