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Tsirkin" , Ani Sinha , Xiao Guangrong , Daniel Henrique Barboza , Greg Kurz , Eric Blake , Eduardo Habkost Subject: Re: [PATCH v3 11/11] machine: Improve error message when using default RAM backend id References: <20230823153412.832081-1-david@redhat.com> <20230823153412.832081-12-david@redhat.com> <209b4b8c.54bc.18a2b7b6f53.Coremail.logoerthiner1@163.com> Date: Fri, 25 Aug 2023 11:10:59 +0200 In-Reply-To: (David Hildenbrand's message of "Fri, 25 Aug 2023 09:36:58 +0200") Message-ID: <87msyfo5b0.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@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_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 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)) { 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 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? * "appending X in Y" should be "appending X to Y". Consider "setting 'memory-backend=%s' with -machine".