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Thu, 18 May 2023 03:18:13 -0700 (PDT) X-Google-Smtp-Source: ACHHUZ6vhXlB6N3MACe83P0I6AEIrkQQlB9B4wSIw20/2OHXcG/TaaC78ygeIVQWNq0mOxGrFy047w== X-Received: by 2002:a17:907:9304:b0:94a:7716:e649 with SMTP id bu4-20020a170907930400b0094a7716e649mr39365596ejc.13.1684405092795; Thu, 18 May 2023 03:18:12 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: armbru@redhat.com Subject: [PATCH 4/4] monitor: do not use mb_read/mb_set for suspend_cnt Date: Thu, 18 May 2023 12:18:04 +0200 Message-Id: <20230518101804.992085-5-pbonzini@redhat.com> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230518101804.992085-1-pbonzini@redhat.com> References: <20230518101804.992085-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@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, 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1684405116148100001 Content-Type: text/plain; charset="utf-8" Clean up monitor_event to just use monitor_suspend/monitor_resume, using mon->mux_out to protect against incorrect nesting (especially on startup). The only remaining case of reading suspend_cnt is in the can_read callback, which is just advisory and can use qatomic_read. As an extra benefit, mux_out is now simply protected by mon_lock. Also, moving the prompt to after the event loop has started removes it from the output in some error cases, where QEMU does not actually start successfully. It is not a full fix and it would be nice to also remove the monitor heading, but this is already a small (though unintentional) improvement. Signed-off-by: Paolo Bonzini --- monitor/hmp.c | 41 ++++++++++++++++------------------- monitor/monitor-internal.h | 3 +-- monitor/monitor.c | 9 ++++++-- tests/qemu-iotests/051.out | 4 ++-- tests/qemu-iotests/051.pc.out | 20 ++++++++--------- 5 files changed, 39 insertions(+), 38 deletions(-) diff --git a/monitor/hmp.c b/monitor/hmp.c index 5cab56d355c8..69c1b7e98abb 100644 --- a/monitor/hmp.c +++ b/monitor/hmp.c @@ -1401,45 +1401,42 @@ static void monitor_read(void *opaque, const uint8_= t *buf, int size) static void monitor_event(void *opaque, QEMUChrEvent event) { Monitor *mon =3D opaque; - MonitorHMP *hmp_mon =3D container_of(mon, MonitorHMP, common); =20 switch (event) { case CHR_EVENT_MUX_IN: qemu_mutex_lock(&mon->mon_lock); - mon->mux_out =3D 0; - qemu_mutex_unlock(&mon->mon_lock); - if (mon->reset_seen) { - readline_restart(hmp_mon->rs); + if (mon->mux_out) { + mon->mux_out =3D 0; monitor_resume(mon); - monitor_flush(mon); - } else { - qatomic_mb_set(&mon->suspend_cnt, 0); } + qemu_mutex_unlock(&mon->mon_lock); break; =20 case CHR_EVENT_MUX_OUT: - if (mon->reset_seen) { - if (qatomic_mb_read(&mon->suspend_cnt) =3D=3D 0) { - monitor_printf(mon, "\n"); - } - monitor_flush(mon); - monitor_suspend(mon); - } else { - qatomic_inc(&mon->suspend_cnt); - } qemu_mutex_lock(&mon->mon_lock); - mon->mux_out =3D 1; + if (!mon->mux_out) { + if (mon->reset_seen && !mon->suspend_cnt) { + monitor_puts_locked(mon, "\n"); + } else { + monitor_flush_locked(mon); + } + monitor_suspend(mon); + mon->mux_out =3D 1; + } qemu_mutex_unlock(&mon->mon_lock); break; =20 case CHR_EVENT_OPENED: monitor_printf(mon, "QEMU %s monitor - type 'help' for more " "information\n", QEMU_VERSION); - if (!mon->mux_out) { - readline_restart(hmp_mon->rs); - readline_show_prompt(hmp_mon->rs); - } + qemu_mutex_lock(&mon->mon_lock); mon->reset_seen =3D 1; + if (!mon->mux_out) { + /* Suspend-resume forces the prompt to be printed. */ + monitor_suspend(mon); + monitor_resume(mon); + } + qemu_mutex_unlock(&mon->mon_lock); mon_refcount++; break; =20 diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h index 53e3808054c7..61c9b6916db3 100644 --- a/monitor/monitor-internal.h +++ b/monitor/monitor-internal.h @@ -94,7 +94,6 @@ typedef struct HMPCommand { =20 struct Monitor { CharBackend chr; - int reset_seen; int suspend_cnt; /* Needs to be accessed atomically */ bool is_qmp; bool skip_flush; @@ -115,8 +114,8 @@ struct Monitor { QLIST_HEAD(, mon_fd_t) fds; GString *outbuf; guint out_watch; - /* Read under either BQL or mon_lock, written with BQL+mon_lock. */ int mux_out; + int reset_seen; }; =20 struct MonitorHMP { diff --git a/monitor/monitor.c b/monitor/monitor.c index 20e33e28d20d..15f97538ef2b 100644 --- a/monitor/monitor.c +++ b/monitor/monitor.c @@ -569,10 +569,15 @@ static void monitor_accept_input(void *opaque) { Monitor *mon =3D opaque; =20 - if (!monitor_is_qmp(mon)) { + qemu_mutex_lock(&mon->mon_lock); + if (!monitor_is_qmp(mon) && mon->reset_seen) { MonitorHMP *hmp_mon =3D container_of(mon, MonitorHMP, common); assert(hmp_mon->rs); + readline_restart(hmp_mon->rs); + qemu_mutex_unlock(&mon->mon_lock); readline_show_prompt(hmp_mon->rs); + } else { + qemu_mutex_unlock(&mon->mon_lock); } =20 qemu_chr_fe_accept_input(&mon->chr); @@ -603,7 +608,7 @@ int monitor_can_read(void *opaque) { Monitor *mon =3D opaque; =20 - return !qatomic_mb_read(&mon->suspend_cnt); + return !qatomic_read(&mon->suspend_cnt); } =20 void monitor_list_append(Monitor *mon) diff --git a/tests/qemu-iotests/051.out b/tests/qemu-iotests/051.out index e5ddb03bda1d..d46215640506 100644 --- a/tests/qemu-iotests/051.out +++ b/tests/qemu-iotests/051.out @@ -74,7 +74,7 @@ QEMU_PROG: -drive file=3DTEST_DIR/t.qcow2,node-name=3Dfoo= #12: Invalid node-name: 'fo =20 Testing: -device virtio-scsi -device scsi-hd QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device scsi-hd: drive property not set +QEMU_PROG: -device scsi-hd: drive property not set =20 =20 =3D=3D=3D Overriding backing file =3D=3D=3D @@ -134,7 +134,7 @@ QEMU X.Y.Z monitor - type 'help' for more information =20 Testing: -drive if=3Dvirtio QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -drive if=3Dvirtio: Device needs media, but drive is emp= ty +QEMU_PROG: -drive if=3Dvirtio: Device needs media, but drive is empty =20 =20 =3D=3D=3D Attach to node in non-default iothread =3D=3D=3D diff --git a/tests/qemu-iotests/051.pc.out b/tests/qemu-iotests/051.pc.out index bade1ff3b929..4d4af5a486df 100644 --- a/tests/qemu-iotests/051.pc.out +++ b/tests/qemu-iotests/051.pc.out @@ -74,7 +74,7 @@ QEMU_PROG: -drive file=3DTEST_DIR/t.qcow2,node-name=3Dfoo= #12: Invalid node-name: 'fo =20 Testing: -device virtio-scsi -device scsi-hd QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device scsi-hd: drive property not set +QEMU_PROG: -device scsi-hd: drive property not set =20 =20 =3D=3D=3D Overriding backing file =3D=3D=3D @@ -142,11 +142,11 @@ QEMU X.Y.Z monitor - type 'help' for more information =20 Testing: -drive if=3Dide QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: Device needs media, but drive is empty +QEMU_PROG: Device needs media, but drive is empty =20 Testing: -drive if=3Dvirtio QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -drive if=3Dvirtio: Device needs media, but drive is emp= ty +QEMU_PROG: -drive if=3Dvirtio: Device needs media, but drive is empty =20 Testing: -drive if=3Dnone,id=3Ddisk -device ide-cd,drive=3Ddisk QEMU X.Y.Z monitor - type 'help' for more information @@ -158,22 +158,22 @@ QEMU X.Y.Z monitor - type 'help' for more information =20 Testing: -drive if=3Dnone,id=3Ddisk -device ide-hd,drive=3Ddisk QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device ide-hd,drive=3Ddisk: Device needs media, but dri= ve is empty +QEMU_PROG: -device ide-hd,drive=3Ddisk: Device needs media, but drive is e= mpty =20 Testing: -drive if=3Dnone,id=3Ddisk -device lsi53c895a -device scsi-hd,dri= ve=3Ddisk QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device scsi-hd,drive=3Ddisk: Device needs media, but dr= ive is empty +QEMU_PROG: -device scsi-hd,drive=3Ddisk: Device needs media, but drive is = empty =20 =20 =3D=3D=3D Attach to node in non-default iothread =3D=3D=3D =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,node-name=3Ddisk -object= iothread,id=3Dthread0 -device virtio-scsi,iothread=3Dthread0,id=3Dvirtio-s= csi0 -device scsi-hd,bus=3Dvirtio-scsi0.0,drive=3Ddisk,share-rw=3Don -devic= e ide-hd,drive=3Ddisk,share-rw=3Don QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device ide-hd,drive=3Ddisk,share-rw=3Don: Cannot change= iothread of active block backend +QEMU_PROG: -device ide-hd,drive=3Ddisk,share-rw=3Don: Cannot change iothre= ad of active block backend =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,node-name=3Ddisk -object= iothread,id=3Dthread0 -device virtio-scsi,iothread=3Dthread0,id=3Dvirtio-s= csi0 -device scsi-hd,bus=3Dvirtio-scsi0.0,drive=3Ddisk,share-rw=3Don -devic= e virtio-blk-pci,drive=3Ddisk,share-rw=3Don QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device virtio-blk-pci,drive=3Ddisk,share-rw=3Don: Canno= t change iothread of active block backend +QEMU_PROG: -device virtio-blk-pci,drive=3Ddisk,share-rw=3Don: Cannot chang= e iothread of active block backend =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,node-name=3Ddisk -object= iothread,id=3Dthread0 -device virtio-scsi,iothread=3Dthread0,id=3Dvirtio-s= csi0 -device scsi-hd,bus=3Dvirtio-scsi0.0,drive=3Ddisk,share-rw=3Don -devic= e lsi53c895a,id=3Dlsi0 -device scsi-hd,bus=3Dlsi0.0,drive=3Ddisk,share-rw= =3Don QEMU X.Y.Z monitor - type 'help' for more information @@ -185,7 +185,7 @@ QEMU X.Y.Z monitor - type 'help' for more information =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,node-name=3Ddisk -object= iothread,id=3Dthread0 -device virtio-scsi,iothread=3Dthread0,id=3Dvirtio-s= csi0 -device scsi-hd,bus=3Dvirtio-scsi0.0,drive=3Ddisk,share-rw=3Don -devic= e virtio-blk-pci,drive=3Ddisk,iothread=3Dthread0,share-rw=3Don QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device virtio-blk-pci,drive=3Ddisk,iothread=3Dthread0,s= hare-rw=3Don: Cannot change iothread of active block backend +QEMU_PROG: -device virtio-blk-pci,drive=3Ddisk,iothread=3Dthread0,share-rw= =3Don: Cannot change iothread of active block backend =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,node-name=3Ddisk -object= iothread,id=3Dthread0 -device virtio-scsi,iothread=3Dthread0,id=3Dvirtio-s= csi0 -device scsi-hd,bus=3Dvirtio-scsi0.0,drive=3Ddisk,share-rw=3Don -devic= e virtio-scsi,id=3Dvirtio-scsi1,iothread=3Dthread0 -device scsi-hd,bus=3Dvi= rtio-scsi1.0,drive=3Ddisk,share-rw=3Don QEMU X.Y.Z monitor - type 'help' for more information @@ -204,7 +204,7 @@ QEMU X.Y.Z monitor - type 'help' for more information =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dide,readonly=3Don QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: Block node is read-only +QEMU_PROG: Block node is read-only =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dvirtio,readonly=3Don QEMU X.Y.Z monitor - type 'help' for more information @@ -220,7 +220,7 @@ QEMU X.Y.Z monitor - type 'help' for more information =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,id=3Ddisk,readonly=3Don = -device ide-hd,drive=3Ddisk QEMU X.Y.Z monitor - type 'help' for more information -(qemu) QEMU_PROG: -device ide-hd,drive=3Ddisk: Block node is read-only +QEMU_PROG: -device ide-hd,drive=3Ddisk: Block node is read-only =20 Testing: -drive file=3DTEST_DIR/t.qcow2,if=3Dnone,id=3Ddisk,readonly=3Don = -device lsi53c895a -device scsi-hd,drive=3Ddisk QEMU X.Y.Z monitor - type 'help' for more information --=20 2.40.1