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[83.57.168.62]) by smtp.gmail.com with ESMTPSA id s3sm8957166wmh.30.2021.10.29.09.11.14 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 29 Oct 2021 09:11:15 -0700 (PDT) Message-ID: Date: Fri, 29 Oct 2021 18:11:14 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [PATCH v2 6/9] qapi: Generalize command policy checking To: Eric Blake , Markus Armbruster References: <20211028102520.747396-1-armbru@redhat.com> <20211028102520.747396-7-armbru@redhat.com> <20211029152811.usdi6bp7wsmlwn2d@redhat.com> From: =?UTF-8?Q?Philippe_Mathieu-Daud=c3=a9?= In-Reply-To: <20211029152811.usdi6bp7wsmlwn2d@redhat.com> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=philmd@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=philmd@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -52 X-Spam_score: -5.3 X-Spam_bar: ----- X-Spam_report: (-5.3 / 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=-2.512, RCVD_IN_DNSWL_LOW=-0.7, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, pkrempa@redhat.com, berrange@redhat.com, ehabkost@redhat.com, qemu-block@nongnu.org, quintela@redhat.com, libvir-list@redhat.com, kchamart@redhat.com, qemu-devel@nongnu.org, mdroth@linux.vnet.ibm.com, dgilbert@redhat.com, pbonzini@redhat.com, marcandre.lureau@redhat.com, jsnow@redhat.com, libguestfs@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/29/21 17:28, Eric Blake wrote: > On Thu, Oct 28, 2021 at 12:25:17PM +0200, Markus Armbruster wrote: >> The code to check command policy can see special feature flag >> 'deprecated' as command flag QCO_DEPRECATED. I want to make feature >> flag 'unstable' visible there as well, so I can add policy for it. >> >> To let me make it visible, add member @special_features (a bitset of >> QapiSpecialFeature) to QmpCommand, and adjust the generator to pass it >> through qmp_register_command(). Then replace "QCO_DEPRECATED in >> @flags" by QAPI_DEPRECATED in @special_features", and drop >> QCO_DEPRECATED. >> >> Signed-off-by: Markus Armbruster >> Reviewed-by: Philippe Mathieu-Daudé >> Acked-by: John Snow >> --- > >> +++ b/qapi/qmp-dispatch.c >> @@ -176,7 +176,7 @@ QDict *qmp_dispatch(const QmpCommandList *cmds, QObject *request, >> "The command %s has not been found", command); >> goto out; >> } >> - if (cmd->options & QCO_DEPRECATED) { >> + if (cmd->special_features & 1u << QAPI_DEPRECATED) { > > I admit having to check the C operator precedence table when reading This doesn't seem a good use of (y)our time. Using a pair of parenthesis is simpler. I expect in a not far future that compilers emit a warning for this. > this (<< is higher than &); if writing it myself, I would probably > have used explicit () to avoid reviewer confusion, but what you have > is correct. (After grepping for ' & 1.*<<' and ' & (1.*<<', it looks > like authors using explicit precedence happens more often, but that > there are other instances in the code base relying on implicit > precedence.) $ git grep -E ' & [0-9a-zA-Z_]+ <<' hw/dma/pl330.c:997: if (~ch->parent->inten & ch->parent->ev_status & 1 << ev_id) { hw/dma/xlnx-zynq-devcfg.c:198: if (s->regs[R_LOCK] & 1 << i) { hw/intc/grlib_irqmp.c:144: if (s->broadcast & 1 << irq) { hw/net/fsl_etsec/rings.c:491: if (etsec->regs[RSTAT].value & 1 << (23 - ring_nbr)) { hw/net/virtio-net.c:748: (n->host_features & 1ULL << VIRTIO_NET_F_MTU)) { hw/pci-host/mv64361.c:812: if ((ch & 0xff << i) && !(val & 0xff << i)) { hw/pci-host/mv64361.c:858: if (s->gpp_int_level && !(val & 0xff << b)) { hw/ssi/xilinx_spi.c:123: qemu_set_irq(s->cs_lines[i], !(~s->regs[R_SPISSR] & 1 << i)); hw/ssi/xilinx_spips.c:441: r[idx[!d]] |= x[idx[d]] & 1 << bit[d] ? 1 << bit[!d] : 0; target/s390x/cpu_features.c:56: if (init[i] & 1ULL << j) { tests/qtest/bios-tables-test.c:209: if (!(val & 1UL << 20 /* HW_REDUCED_ACPI */)) { Not that many.