From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 937B4606A32E for ; Wed, 11 Nov 2026 12:45:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=dfGLHpgS Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xR7hW-0001Rw-Bm; Wed, 11 Nov 2026 07:45:18 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xR7hV-0001Oo-5Q for qemu-devel@nongnu.org; Wed, 11 Nov 2026 07:45:17 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xR7hS-0000n4-V6 for qemu-devel@nongnu.org; Wed, 11 Nov 2026 07:45:16 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1794401113; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eCzP4uZCvMCgsSiM9GqgqtzAhNl4j+dxe/yaViCyuD0=; b=dfGLHpgSsAiaXZt2Wtu++vi/3xIWfQ0ohl8Ru3UltNlPM28UafFMoZKMW668lti7xhSb1L jiGQ6uJt0q1TEHUGLXJNdjVQHUxjGJD7+BUM2XnLvP1eqnXNLaul7OMeRTZBnTQR7tbRkj 8JoCG1maKW8gOb0rjBO+peCN5Dcnsxg= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-456-ok_pTUAoM1KOywlcZ0qAiQ-1; Wed, 11 Nov 2026 07:45:10 -0500 X-MC-Unique: ok_pTUAoM1KOywlcZ0qAiQ-1 X-Mimecast-MFC-AGG-ID: ok_pTUAoM1KOywlcZ0qAiQ_1794401109 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D206A1802573; Wed, 11 Nov 2026 12:45:08 +0000 (UTC) Received: from redhat.com (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 767941800545; Wed, 11 Nov 2026 12:45:07 +0000 (UTC) Date: Wed, 11 Nov 2026 12:45:04 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, david@kernel.org, imammedo@redhat.com, peter.maydell@linaro.org Subject: Re: [PATCH 1/7] backends/hostmem: Drop redundant validation of property "size" Message-ID: References: <20261111122342.634370-1-armbru@redhat.com> <20261111122342.634370-2-armbru@redhat.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20261111122342.634370-2-armbru@redhat.com> User-Agent: Mutt/2.4.3 (2026-10-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 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_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-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: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-17.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Wed, Nov 11, 2026 at 01:23:36PM +0100, Markus Armbruster wrote: > Property "size" is mandatory, and its setter > host_memory_backend_set_size() rejects value zero. Delete the > redundant checks for zero in the .alloc() callbacks. > > Signed-off-by: Markus Armbruster > --- > backends/hostmem-epc.c | 5 ----- > backends/hostmem-file.c | 4 ---- > backends/hostmem-memfd.c | 5 ----- > backends/hostmem-ram.c | 5 ----- > backends/hostmem-shm.c | 5 ----- > 5 files changed, 24 deletions(-) Reviewed-by: Daniel P. Berrangé ...it is a shame this was/is dead code, since the actual error message from host_memory_backend_set_size() is (IMHO) worse than that from the unreachable code you're deleting $ ./build/qemu-system-x86_64 -object memory-backend-ram,size=0,id=foo qemu-system-x86_64: property 'size' of memory-backend-ram doesn't take value '0' as a separate patch I might suggest diff --git a/backends/hostmem.c b/backends/hostmem.c index 173d042be35..f523dce6eb0 100644 --- a/backends/hostmem.c +++ b/backends/hostmem.c @@ -77,8 +77,8 @@ host_memory_backend_set_size(Object *obj, Visitor *v, const char *name, } if (!value) { error_setg(errp, - "property '%s' of %s doesn't take value '%" PRIu64 "'", - name, object_get_typename(obj), value); + "cannot create '%s' with a size of 0", + object_get_typename(obj)); return; } backend->size = value; so that we get the nicer message: $ ./build/qemu-system-x86_64 -object memory-backend-ram,size=0,id=foo qemu-system-x86_64: cannot create 'memory-backend-ram' with a size of 0 > > diff --git a/backends/hostmem-epc.c b/backends/hostmem-epc.c > index ab20b182331..e1c784249ff 100644 > --- a/backends/hostmem-epc.c > +++ b/backends/hostmem-epc.c > @@ -24,11 +24,6 @@ sgx_epc_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) > uint32_t ram_flags; > int fd; > > - if (!backend->size) { > - error_setg(errp, "can't create backend with size 0"); > - return false; > - } > - > fd = qemu_open("/dev/sgx_vepc", O_RDWR, errp); > if (fd < 0) { > return false; > diff --git a/backends/hostmem-file.c b/backends/hostmem-file.c > index 6ad9cad0320..08d0382d76f 100644 > --- a/backends/hostmem-file.c > +++ b/backends/hostmem-file.c > @@ -48,10 +48,6 @@ file_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) > g_autofree gchar *name = NULL; > uint32_t ram_flags; > > - if (!backend->size) { > - error_setg(errp, "can't create backend with size 0"); > - return false; > - } > if (!fb->mem_path) { > error_setg(errp, "mem-path property not set"); > return false; > diff --git a/backends/hostmem-memfd.c b/backends/hostmem-memfd.c > index 46489212a23..11d456e3ebd 100644 > --- a/backends/hostmem-memfd.c > +++ b/backends/hostmem-memfd.c > @@ -49,11 +49,6 @@ memfd_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) > int fd = cpr_find_fd(name, 0); > uint32_t ram_flags; > > - if (!backend->size) { > - error_setg(errp, "can't create backend with size 0"); > - return false; > - } > - > if (fd >= 0) { > goto have_fd; > } > diff --git a/backends/hostmem-ram.c b/backends/hostmem-ram.c > index 6a507fad77c..0ae7b4ae759 100644 > --- a/backends/hostmem-ram.c > +++ b/backends/hostmem-ram.c > @@ -22,11 +22,6 @@ ram_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) > g_autofree char *name = NULL; > uint32_t ram_flags; > > - if (!backend->size) { > - error_setg(errp, "can't create backend with size 0"); > - return false; > - } > - > name = host_memory_backend_get_name(backend); > ram_flags = backend->share ? RAM_SHARED : RAM_PRIVATE; > ram_flags |= backend->reserve ? 0 : RAM_NORESERVE; > diff --git a/backends/hostmem-shm.c b/backends/hostmem-shm.c > index adf60957c3c..0a01c760551 100644 > --- a/backends/hostmem-shm.c > +++ b/backends/hostmem-shm.c > @@ -30,11 +30,6 @@ shm_backend_memory_alloc(HostMemoryBackend *backend, Error **errp) > uint32_t ram_flags; > int fd = cpr_find_fd(backend_name, 0); > > - if (!backend->size) { > - error_setg(errp, "can't create shm backend with size 0"); > - return false; > - } > - > if (!backend->share) { > error_setg(errp, "can't create shm backend with `share=off`"); > return false; > -- > 2.55.0 > With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|