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b=GTzm0oQafmhBu6heaOXi6vSdU8aglkWCp5Zm1MpRixe/fBmenaugQPDlcgmjtk/DZIPHgo OWcQFi45fqAbQHDQ== Received: from imap1.dmz-prg2.suse.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by imap1.dmz-prg2.suse.org (Postfix) with ESMTPS id 8BC6D139D4; Thu, 27 Mar 2025 14:39:39 +0000 (UTC) Received: from dovecot-director2.suse.de ([2a07:de40:b281:106:10:150:64:167]) by imap1.dmz-prg2.suse.org with ESMTPSA id iJseEytj5WcVZgAAD6G6ig (envelope-from ); Thu, 27 Mar 2025 14:39:39 +0000 From: Fabiano Rosas To: qemu-devel@nongnu.org Cc: Peter Xu , Prasad Pandit , Juraj Marcin , berrange@redhat.com, Marco Cavenati Subject: [PATCH 1/4] migration/savevm: Add a compatibility check for capabilities Date: Thu, 27 Mar 2025 11:39:31 -0300 Message-Id: <20250327143934.7935-2-farosas@suse.de> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20250327143934.7935-1-farosas@suse.de> References: <20250327143934.7935-1-farosas@suse.de> MIME-Version: 1.0 X-Spamd-Result: default: False [-2.80 / 50.00]; BAYES_HAM(-3.00)[99.99%]; MID_CONTAINS_FROM(1.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000]; R_MISSING_CHARSET(0.50)[]; NEURAL_HAM_SHORT(-0.20)[-1.000]; MIME_GOOD(-0.10)[text/plain]; MIME_TRACE(0.00)[0:+]; TO_DN_SOME(0.00)[]; RCVD_VIA_SMTP_AUTH(0.00)[]; ARC_NA(0.00)[]; DKIM_SIGNED(0.00)[suse.de:s=susede2_rsa,suse.de:s=susede2_ed25519]; FUZZY_BLOCKED(0.00)[rspamd.com]; FROM_EQ_ENVFROM(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_FIVE(0.00)[6]; RCVD_COUNT_TWO(0.00)[2]; TO_MATCH_ENVRCPT_ALL(0.00)[]; DBL_BLOCKED_OPENRESOLVER(0.00)[imap1.dmz-prg2.suse.org:helo,suse.de:mid,suse.de:email]; RCVD_TLS_ALL(0.00)[] Received-SPF: pass client-ip=195.135.223.131; envelope-from=farosas@suse.de; helo=smtp-out2.suse.de X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org It has always been possible to enable arbitrary migration capabilities and attempt to take a snapshot of the VM with the savevm/loadvm commands as well as their QMP counterparts snapshot-save/snapshot-load. Most migration capabilities are not meant to be used with snapshots and there's a risk of crashing QEMU or producing incorrect behavior. Ideally, every migration capability would either be implemented for savevm or explicitly rejected. Add a compatibility check routine and reject the snapshot command if an incompatible capability is enabled. For now only act on the the two that actually cause a crash: multifd and mapped-ram. Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2881 Signed-off-by: Fabiano Rosas --- migration/options.c | 26 ++++++++++++++++++++++++++ migration/options.h | 1 + migration/savevm.c | 8 ++++++++ 3 files changed, 35 insertions(+) diff --git a/migration/options.c b/migration/options.c index b0ac2ea408..8772b98dca 100644 --- a/migration/options.c +++ b/migration/options.c @@ -443,11 +443,37 @@ INITIALIZE_MIGRATE_CAPS_SET(check_caps_background_snapshot, MIGRATION_CAPABILITY_VALIDATE_UUID, MIGRATION_CAPABILITY_ZERO_COPY_SEND); +/* Snapshot compatibility check list */ +static const +INITIALIZE_MIGRATE_CAPS_SET(check_caps_savevm, + MIGRATION_CAPABILITY_MULTIFD, + MIGRATION_CAPABILITY_MAPPED_RAM, +); + static bool migrate_incoming_started(void) { return !!migration_incoming_get_current()->transport_data; } +bool migrate_can_snapshot(Error **errp) +{ + MigrationState *s = migrate_get_current(); + int i; + + for (i = 0; i < check_caps_savevm.size; i++) { + int incomp_cap = check_caps_savevm.caps[i]; + + if (s->capabilities[incomp_cap]) { + error_setg(errp, + "Snapshots are not compatible with %s", + MigrationCapability_str(incomp_cap)); + return false; + } + } + + return true; +} + /** * @migration_caps_check - check capability compatibility * diff --git a/migration/options.h b/migration/options.h index 762be4e641..20b71b6f2a 100644 --- a/migration/options.h +++ b/migration/options.h @@ -58,6 +58,7 @@ bool migrate_tls(void); /* capabilities helpers */ bool migrate_caps_check(bool *old_caps, bool *new_caps, Error **errp); +bool migrate_can_snapshot(Error **errp); /* parameters */ diff --git a/migration/savevm.c b/migration/savevm.c index ce158c3512..3be13bcfe8 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -3229,6 +3229,10 @@ bool save_snapshot(const char *name, bool overwrite, const char *vmstate, GLOBAL_STATE_CODE(); + if (!migrate_can_snapshot(errp)) { + return false; + } + if (migration_is_blocked(errp)) { return false; } @@ -3413,6 +3417,10 @@ bool load_snapshot(const char *name, const char *vmstate, int ret; MigrationIncomingState *mis = migration_incoming_get_current(); + if (!migrate_can_snapshot(errp)) { + return false; + } + if (!bdrv_all_can_snapshot(has_devices, devices, errp)) { return false; }