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Fri, 14 Feb 2025 20:12:35 GMT Received: from pps.reinject (localhost [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 44nwqm6nmh-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 14 Feb 2025 20:12:35 +0000 Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 51EK8wKA036189; Fri, 14 Feb 2025 20:12:34 GMT Received: from ca-dev63.us.oracle.com (ca-dev63.us.oracle.com [10.211.8.221]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTP id 44nwqm6nkx-1; Fri, 14 Feb 2025 20:12:34 +0000 From: Steve Sistare To: qemu-devel@nongnu.org Cc: Peter Xu , Fabiano Rosas , David Hildenbrand , Philippe Mathieu-Daude , Paolo Bonzini , Steve Sistare Subject: [PATCH V2] migration: ram block cpr blockers Date: Fri, 14 Feb 2025 12:12:33 -0800 Message-Id: <1739563953-227207-1-git-send-email-steven.sistare@oracle.com> X-Mailer: git-send-email 1.8.3.1 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-02-14_08,2025-02-13_01,2024-11-22_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxlogscore=999 phishscore=0 malwarescore=0 mlxscore=0 spamscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2501170000 definitions=main-2502140138 X-Proofpoint-ORIG-GUID: DLbSv6d-Q11f8kX8QWPHAtfo_UlpA0By X-Proofpoint-GUID: DLbSv6d-Q11f8kX8QWPHAtfo_UlpA0By Received-SPF: pass client-ip=205.220.177.32; envelope-from=steven.sistare@oracle.com; helo=mx0b-00069f02.pphosted.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, 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 Unlike cpr-reboot mode, cpr-transfer mode cannot save volatile ram blocks in the migration stream file and recreate them later, because the physical memory for the blocks is pinned and registered for vfio. Add a blocker for volatile ram blocks. Also add a blocker for RAM_GUEST_MEMFD. Preserving guest_memfd may be sufficient for CPR, but it has not been tested yet. Signed-off-by: Steve Sistare Reviewed-by: Fabiano Rosas Reviewed-by: Peter Xu --- include/exec/memory.h | 3 +++ include/exec/ramblock.h | 1 + migration/savevm.c | 2 ++ system/physmem.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++ 4 files changed, 74 insertions(+) diff --git a/include/exec/memory.h b/include/exec/memory.h index 9f73b59..ea5d33a 100644 --- a/include/exec/memory.h +++ b/include/exec/memory.h @@ -3184,6 +3184,9 @@ bool ram_block_discard_is_disabled(void); */ bool ram_block_discard_is_required(void); +void ram_block_add_cpr_blocker(RAMBlock *rb, Error **errp); +void ram_block_del_cpr_blocker(RAMBlock *rb); + #endif #endif diff --git a/include/exec/ramblock.h b/include/exec/ramblock.h index 0babd10..64484cd 100644 --- a/include/exec/ramblock.h +++ b/include/exec/ramblock.h @@ -39,6 +39,7 @@ struct RAMBlock { /* RCU-enabled, writes protected by the ramlist lock */ QLIST_ENTRY(RAMBlock) next; QLIST_HEAD(, RAMBlockNotifier) ramblock_notifiers; + Error *cpr_blocker; int fd; uint64_t fd_offset; int guest_memfd; diff --git a/migration/savevm.c b/migration/savevm.c index bc375db..85a3559 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -3315,12 +3315,14 @@ void vmstate_register_ram(MemoryRegion *mr, DeviceState *dev) qemu_ram_set_idstr(mr->ram_block, memory_region_name(mr), dev); qemu_ram_set_migratable(mr->ram_block); + ram_block_add_cpr_blocker(mr->ram_block, &error_fatal); } void vmstate_unregister_ram(MemoryRegion *mr, DeviceState *dev) { qemu_ram_unset_idstr(mr->ram_block); qemu_ram_unset_migratable(mr->ram_block); + ram_block_del_cpr_blocker(mr->ram_block); } void vmstate_register_ram_global(MemoryRegion *mr) diff --git a/system/physmem.c b/system/physmem.c index 67c9db9..c416068 100644 --- a/system/physmem.c +++ b/system/physmem.c @@ -70,7 +70,10 @@ #include "qemu/pmem.h" +#include "qapi/qapi-types-migration.h" +#include "migration/blocker.h" #include "migration/cpr.h" +#include "migration/options.h" #include "migration/vmstate.h" #include "qemu/range.h" @@ -1899,6 +1902,14 @@ static void ram_block_add(RAMBlock *new_block, Error **errp) qemu_mutex_unlock_ramlist(); goto out_free; } + + error_setg(&new_block->cpr_blocker, + "Memory region %s uses guest_memfd, " + "which is not supported with CPR.", + memory_region_name(new_block->mr)); + migrate_add_blocker_modes(&new_block->cpr_blocker, errp, + MIG_MODE_CPR_TRANSFER, + -1); } ram_size = (new_block->offset + new_block->max_length) >> TARGET_PAGE_BITS; @@ -4059,3 +4070,60 @@ bool ram_block_discard_is_required(void) return qatomic_read(&ram_block_discard_required_cnt) || qatomic_read(&ram_block_coordinated_discard_required_cnt); } + +/* + * Return true if ram contents would be lost during CPR. Do not exclude rom, + * because the rom file could change in new QEMU. + */ +static bool ram_is_volatile(RAMBlock *rb) +{ + MemoryRegion *mr = rb->mr; + + if (!mr || !memory_region_is_ram(mr)) { + return false; + } + + /* Ram device is remapped in new QEMU */ + if (memory_region_is_ram_device(mr)) { + return false; + } + + /* Named files are remapped in new QEMU, same contents if shared (no COW) */ + if (qemu_ram_is_shared(rb) && qemu_ram_is_named_file(rb)) { + return false; + } + + /* A file descriptor is remapped in new QEMU */ + if (rb->fd >= 0) { + return false; + } + + return true; +} + +/* + * Add a blocker for each volatile ram block. This function should only be + * called after we know that the block is migratable. Non-migratable blocks + * are either re-created in new QEMU, or are handled specially, or are covered + * by a device-level CPR blocker. + */ +void ram_block_add_cpr_blocker(RAMBlock *rb, Error **errp) +{ + assert(qemu_ram_is_migratable(rb)); + + if (!ram_is_volatile(rb)) { + return; + } + + error_setg(&rb->cpr_blocker, + "Memory region %s is volatile. share=on is required for " + "memory-backend objects, and aux-ram-share=on is required.", + memory_region_name(rb->mr)); + migrate_add_blocker_modes(&rb->cpr_blocker, errp, MIG_MODE_CPR_TRANSFER, + -1); +} + +void ram_block_del_cpr_blocker(RAMBlock *rb) +{ + migrate_del_blocker(&rb->cpr_blocker); +}