{"id":2224771,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2224771/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260418115230.17809-1-viking4@gmail.com/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/1.1/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20260418115230.17809-1-viking4@gmail.com>","date":"2026-04-18T11:52:30","name":"chardev/msmouse: save and restore device state for migration and savevm","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"d4e46700c1d849747dcb109674e632b323492f81","submitter":{"id":92831,"url":"http://patchwork.ozlabs.org/api/1.1/people/92831/?format=json","name":"Trieu Huynh","email":"vikingtc4@gmail.com"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260418115230.17809-1-viking4@gmail.com/mbox/","series":[{"id":500438,"url":"http://patchwork.ozlabs.org/api/1.1/series/500438/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=500438","date":"2026-04-18T11:52:30","name":"chardev/msmouse: save and restore device state for migration and savevm","version":1,"mbox":"http://patchwork.ozlabs.org/series/500438/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2224771/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2224771/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20251104 header.b=n7izcMiS;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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helo=mail-pg1-x534.google.com","X-Spam_score_int":"-17","X-Spam_score":"-1.8","X-Spam_bar":"-","X-Spam_report":"(-1.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n FREEMAIL_ENVFROM_END_DIGIT=0.25, FREEMAIL_FROM=0.001,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n 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-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"From: Trieu Huynh \n\nMouseChardev holds state that must survive migration and savevm/loadvm:\n\n tiocm - serial line control (RTS/DTR). When zero the mouse is\n considered powered-off and all input events are silently\n dropped. Losing this field after migration leaves the\n mouse in a dead state: the guest driver must toggle\n RTS/DTR again to re-detect the mouse, which most drivers\n (Linux sermouse, DOS ctmouse) only do at initialisation.\n\n axis[] - accumulated X/Y movement not yet encoded into a packet.\n\n btns[] - current button state.\n\n btnc[] - per-button change flags used for middle-button tracking.\n\n outbuf - Fifo8 of encoded mouse bytes waiting to be delivered to\n the serial port receive FIFO.\n\nAdd a VMStateDescription covering all five fields, registering it in\nmsmouse_chr_open and unregistering it in char_msmouse_finalize. This\nfollows the same pattern used by ui/vdagent.c\n\nResolves: https://gitlab.com/qemu-project/qemu/-/issues/1234\n\nSigned-off-by: Trieu Huynh \n---\nSteps to reproduce:\n\n* 1. Starting source QEMU under GDB\ngdb -q ./qemu-system-x86_64\n\n* Inside GDB:\n\n(gdb) set args -chardev msmouse,id=mouse0 \\\n -device isa-serial,chardev=mouse0 \\\n - \n\n(gdb) break msmouse_input_sync\n(gdb) run\n\n* 2. Starting destination QEMU under GDB\ngdb -q ./qemu-system-x86_64\n\n* Inside GDB:\n\n(gdb) set args -chardev msmouse,id=mouse0 \\\n -S -incoming tcp:0:4444\n -device isa-serial,chardev=mouse0 \\\n - \n\n(gdb) break msmouse_chr_ioctl\n(gdb) run\n\n\n* 3. Send mouse events to source\n{\"execute\":\"qmp_capabilities\"}\n\n* Power on the mouse:\n{\"execute\":\"human-monitor-command\",\"arguments\":{\"command-line\":\"o 0x2fc 0x03\"}}\n\n* Inject a movement event with buttons:\n{\"execute\":\"input-send-event\",\"arguments\":{\"events\":[{\"type\":\"rel\",\"data\":{\"axis\":\"x\",\"value\":30}},{\"type\":\"rel\",\"data\":{\"axis\":\"y\",\"value\":-10}},{\"type\":\"btn\",\"data\":{\"button\":\"left\",\"down\":true}},{\"type\":\"btn\",\"data\":{\"button\":\"middle\",\"down\":true}}]}}\n\nThread 1 \"qemu-system-x86\" hit Breakpoint 1, msmouse_input_sync (dev=0x555557648a00)\n at ../chardev/msmouse.c:171\n171\t MouseChardev *mouse = MOUSE_CHARDEV(dev);\n(gdb) next\n172\t Chardev *chr = CHARDEV(dev);\n(gdb) next\n175\t if (!MSMOUSE_PWR(mouse->tiocm)) {\n(gdb) print mouse->tiocm\n$17 = 6\n(gdb) print mouse->axis[1]\n$18 = -10\n(gdb) print mouse->axis[0]\n$19 = 30\n(gdb) print mouse->btns[0]\n$20 = true\n(gdb) print mouse->btns[2]\n$21 = false\n(gdb) print mouse->btnc[0]\n$22 = true\n(gdb) print mouse->btnc[2]\n$23 = false\n(gdb) print mouse->outbuf \n$24 = {data = 0x5555578bbdf0 \"M3\\b\\001$1-5\\020\\020\\020\\021<<-/53%<<1%-5\", capacity = 64, \n head = 1, num = 55}\n(gdb) continue\n\n* 4. Start migration until completed\n\n{\"execute\":\"migrate\",\"arguments\":{\"uri\":\"tcp:127.0.0.1:4444\"}}\n\n* 5. Verify mouse data on dest\n\n* As-is:\nThread 1 \"qemu-system-x86\" hit Breakpoint 1, msmouse_chr_ioctl (chr=0x555557648ad0, \n cmd=1, arg=0x7ffff415ba80) at ../chardev/msmouse.c:182\n182\t{\n(gdb) next\n183\t MouseChardev *mouse = MOUSE_CHARDEV(chr);\n(gdb) next\n184\t int c, i, j;\n(gdb) print ((MouseChardev *)chr)->tiocm\n$1 = 0\n(gdb) print ((MouseChardev *)chr)->axis[0]\n$2 = 0\n(gdb) print ((MouseChardev *)chr)->axis[1]\n$3 = 0\n(gdb) print ((MouseChardev *)chr)->btns[0]\n$4 = false\n(gdb) print ((MouseChardev *)chr)->btns[2]\n$5 = false\n(gdb) print ((MouseChardev *)chr)->btnc[0]\n$6 = false\n(gdb) print ((MouseChardev *)chr)->btnc[2]\n$7 = false\n(gdb) print ((MouseChardev *)chr)->outbuf\n$8 = {data = 0x5555578bbf60 \"\\273xUU\\005\", capacity = 64, head = 0, num = 0}\n(gdb) \n\n* To-be:\nThread 1 \"qemu-system-x86\" hit Breakpoint 1, msmouse_chr_ioctl (chr=0x555557648ad0, \n cmd=1, arg=0x7ffff415ba80) at ../chardev/msmouse.c:197\n197 {\n(gdb) next\n198 MouseChardev *mouse = MOUSE_CHARDEV(chr);\n(gdb) next\n199 int c, i, j;\n(gdb) print ((MouseChardev *)chr)->tiocm\n$1 = 6\n(gdb) print ((MouseChardev *)chr)->axis[0]\n$2 = 0\n(gdb) print ((MouseChardev *)chr)->axis[1]\n$3 = 0\n(gdb) print ((MouseChardev *)chr)->btns[0]\n$4 = true\n(gdb) print ((MouseChardev *)chr)->btns[2]\n$5 = false\n(gdb) print ((MouseChardev *)chr)->btnc[0]\n$6 = true\n(gdb) print ((MouseChardev *)chr)->btnc[2]\n$7 = false\n(gdb) print ((MouseChardev *)chr)->outbuf\n$8 = {data = 0x5555578bbf60 \"M3\\b\\001$1-5\\020\\020\\020\\021<<-/53%<<1%-5\", capacity = 64, \n head = 1, num = 59}\n\n chardev/msmouse.c | 17 +++++++++++++++++\n 1 file changed, 17 insertions(+)","diff":"diff --git a/chardev/msmouse.c b/chardev/msmouse.c\nindex 365f04546e..e991135be9 100644\n--- a/chardev/msmouse.c\n+++ b/chardev/msmouse.c\n@@ -30,6 +30,7 @@\n #include \"ui/console.h\"\n #include \"ui/input.h\"\n #include \"qom/object.h\"\n+#include \"migration/vmstate.h\"\n \n #define MSMOUSE_LO6(n) ((n) & 0x3f)\n #define MSMOUSE_HI2(n) (((n) & 0xc0) >> 6)\n@@ -70,6 +71,20 @@ typedef struct MouseChardev MouseChardev;\n DECLARE_INSTANCE_CHECKER(MouseChardev, MOUSE_CHARDEV,\n TYPE_CHARDEV_MSMOUSE)\n \n+static const VMStateDescription vmstate_msmouse = {\n+ .name = \"msmouse\",\n+ .version_id = 1,\n+ .minimum_version_id = 1,\n+ .fields = (const VMStateField[]) {\n+ VMSTATE_INT32(tiocm, MouseChardev),\n+ VMSTATE_INT32_ARRAY(axis, MouseChardev, INPUT_AXIS__MAX),\n+ VMSTATE_BOOL_ARRAY(btns, MouseChardev, INPUT_BUTTON__MAX),\n+ VMSTATE_BOOL_ARRAY(btnc, MouseChardev, INPUT_BUTTON__MAX),\n+ VMSTATE_FIFO8(outbuf, MouseChardev),\n+ VMSTATE_END_OF_LIST()\n+ },\n+};\n+\n static void msmouse_chr_accept_input(Chardev *chr)\n {\n MouseChardev *mouse = MOUSE_CHARDEV(chr);\n@@ -247,6 +262,7 @@ static void char_msmouse_finalize(Object *obj)\n {\n MouseChardev *mouse = MOUSE_CHARDEV(obj);\n \n+ vmstate_unregister(NULL, &vmstate_msmouse, mouse);\n if (mouse->hs) {\n qemu_input_handler_unregister(mouse->hs);\n }\n@@ -263,6 +279,7 @@ static bool msmouse_chr_open(Chardev *chr,\n &msmouse_handler);\n mouse->tiocm = 0;\n fifo8_create(&mouse->outbuf, MSMOUSE_BUF_SZ);\n+ vmstate_register_any(NULL, &vmstate_msmouse, mouse);\n \n /* Never send CHR_EVENT_OPENED */\n return true;\n","prefixes":[]}