{"id":2215597,"url":"http://patchwork.ozlabs.org/api/patches/2215597/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260324194333.30004-12-farosas@suse.de/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/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":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260324194333.30004-12-farosas@suse.de>","list_archive_url":null,"date":"2026-03-24T19:43:26","name":"[RFC,v1,11/17] vmstate: Introduce vmstate_first","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"985c1e9800becaa95ddb3fed02a89f9aa90d7661","submitter":{"id":85343,"url":"http://patchwork.ozlabs.org/api/people/85343/?format=json","name":"Fabiano Rosas","email":"farosas@suse.de"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260324194333.30004-12-farosas@suse.de/mbox/","series":[{"id":497339,"url":"http://patchwork.ozlabs.org/api/series/497339/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=497339","date":"2026-03-24T19:43:16","name":"migration: vmstate_save|load changes for peterx","version":1,"mbox":"http://patchwork.ozlabs.org/series/497339/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2215597/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2215597/checks/","tags":{},"related":[],"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 (1024-bit key;\n unprotected) header.d=suse.de header.i=@suse.de header.a=rsa-sha256\n header.s=susede2_rsa header.b=KK/Wsw8n;\n\tdkim=pass header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=jK1wwOn9;\n\tdkim=pass (1024-bit key) header.d=suse.de header.i=@suse.de\n header.a=rsa-sha256 header.s=susede2_rsa header.b=KK/Wsw8n;\n\tdkim=neutral header.d=suse.de header.i=@suse.de header.a=ed25519-sha256\n header.s=susede2_ed25519 header.b=jK1wwOn9;\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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t=1774381433;\n h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:\n mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=ijgwsSEpVbXrAjpHcIRFYxo7WBxDWTudU7OG4QHJ3AQ=;\n b=jK1wwOn9VzlTE8+Yutb/mw+hg0HecGqRmukR9r38aPbSQhprMMU9NvlF8XWLCc8jEkYRdN\n P1+pXKwJRkf/9RCg=="],"From":"Fabiano Rosas ","To":"qemu-devel@nongnu.org","Cc":"Peter Xu ,\n Alexander Mikhalitsyn ,\n Juraj Marcin ","Subject":"[RFC PATCH v1 11/17] vmstate: Introduce vmstate_first","Date":"Tue, 24 Mar 2026 16:43:26 -0300","Message-ID":"<20260324194333.30004-12-farosas@suse.de>","X-Mailer":"git-send-email 2.51.0","In-Reply-To":"<20260324194333.30004-1-farosas@suse.de>","References":"<20260324194333.30004-1-farosas@suse.de>","MIME-Version":"1.0","Content-Transfer-Encoding":"8bit","X-Spam-Score":"-2.80","X-Spamd-Result":"default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[100.00%];\n NEURAL_HAM_LONG(-1.00)[-1.000]; MID_CONTAINS_FROM(1.00)[];\n R_MISSING_CHARSET(0.50)[]; 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Introduce a getter for the\nfirst field. Take field->flags into consideration and also allocate\nmemory when necessary.\n\nSigned-off-by: Fabiano Rosas \n---\nmaybe we can soon have an iterator\n---\n migration/vmstate.c | 67 +++++++++++++++++++++++++--------------------\n 1 file changed, 38 insertions(+), 29 deletions(-)","diff":"diff --git a/migration/vmstate.c b/migration/vmstate.c\nindex 85e63305f6..ab7c6fa4ab 100644\n--- a/migration/vmstate.c\n+++ b/migration/vmstate.c\n@@ -100,23 +100,31 @@ static int vmstate_size(void *opaque, const VMStateField *field)\n return size;\n }\n \n-static void *vmstate_handle_alloc(void *ptr, const VMStateField *field,\n- int size, int n_elems)\n+static void *vmstate_handle_alloc(void **ptr, int size, int n_elems)\n {\n- void *new = ptr;\n+ size *= n_elems;\n+ if (size) {\n+ *ptr = g_malloc(size);\n+ }\n+\n+ return *ptr;\n+}\n+\n+static void *vmstate_first(void *opaque, const VMStateField *field,\n+ int size, int n, bool alloc)\n+{\n+ void **first = opaque + field->offset;\n+\n+ if (alloc) {\n+ return vmstate_handle_alloc(first, size, n);\n+ }\n \n if (field->flags & VMS_POINTER) {\n- if (field->flags & VMS_ALLOC) {\n- size *= n_elems;\n- if (size) {\n- new = g_malloc(size);\n- *(void **)ptr = new;\n- }\n- }\n- assert(new || !n_elems || !size);\n- return *(void **)ptr;\n+ assert(first || !n || !size);\n+ return *first;\n }\n- return new;\n+\n+ return first;\n }\n \n static bool vmstate_ptr_marker_load(QEMUFile *f, bool *load_field,\n@@ -251,11 +259,12 @@ bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,\n trace_vmstate_load_state_field(vmsd->name, field->name, exists);\n \n if (exists) {\n- void *first_elem = opaque + field->offset;\n+ void *head;\n int i, n_elems = vmstate_n_elems(opaque, field);\n int size = vmstate_size(opaque, field);\n \n- first_elem = vmstate_handle_alloc(first_elem, field, size, n_elems);\n+ head = vmstate_first(opaque, field, size, n_elems,\n+ field->flags & VMS_ALLOC);\n \n for (i = 0; i < n_elems; i++) {\n /* If we will process the load of field? */\n@@ -264,7 +273,7 @@ bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,\n void *curr_elem;\n \n if (field->flags & VMS_ARRAY_OF_POINTER) {\n- void **array_elem = (void **)first_elem + i;\n+ void **array_elem = (void **)head + i;\n bool use_dynamic_array =\n field->flags & VMS_ARRAY_OF_POINTER_AUTO_ALLOC;\n bool use_marker_field;\n@@ -290,13 +299,13 @@ bool vmstate_load_vmsd(QEMUFile *f, const VMStateDescription *vmsd,\n * need the object size, not entry size of the\n * array.\n */\n- curr_elem = g_malloc0(field->size);\n- /* Remember to update the root pointer! */\n- *(void **)array_elem = curr_elem;\n+ assert(!curr_elem);\n+ curr_elem = vmstate_handle_alloc(array_elem,\n+ field->size, 1);\n }\n }\n } else {\n- curr_elem = first_elem + size * i;\n+ curr_elem = head + size * i;\n }\n \n if (load_field) {\n@@ -627,28 +636,26 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,\n \n while (field->name) {\n if (vmstate_field_exists(vmsd, field, opaque, version_id)) {\n- void *first_elem = opaque + field->offset;\n+ void *head;\n int i, n_elems = vmstate_n_elems(opaque, field);\n int size = vmstate_size(opaque, field);\n bool is_null_prev = false;\n bool use_vmdesc = true;\n \n trace_vmstate_save_state_loop(vmsd->name, field->name, n_elems);\n- if (field->flags & VMS_POINTER) {\n- first_elem = *(void **)first_elem;\n- assert(first_elem || !n_elems || !size);\n- }\n+ head = vmstate_first(opaque, field, size, n_elems, false);\n \n for (i = 0; i < n_elems; i++) {\n bool save_field = true;\n- void *curr_elem = first_elem + size * i;\n+ void *curr_elem;\n int max_elems = n_elems - i;\n \n if (field->flags & VMS_ARRAY_OF_POINTER) {\n bool use_marker_field, is_null, use_dynamic_array;\n+ void **array_elem = (void **)head + i;\n \n- assert(curr_elem);\n- curr_elem = *(void **)curr_elem;\n+ assert(array_elem);\n+ curr_elem = *array_elem;\n \n is_null = !curr_elem;\n \n@@ -681,7 +688,7 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,\n use_vmdesc = true;\n \n for (int j = i + 1; j < n_elems; j++) {\n- void *elem = *(void **)(first_elem + size * j);\n+ void *elem = *(void **)(head + size * j);\n bool elem_is_null = !elem;\n \n if (is_null != elem_is_null) {\n@@ -706,6 +713,8 @@ static bool vmstate_save_vmsd_v(QEMUFile *f, const VMStateDescription *vmsd,\n \n save_field = !!curr_elem;\n }\n+ } else {\n+ curr_elem = head + size * i;\n }\n \n if (save_field) {\n","prefixes":["RFC","v1","11/17"]}