From 7afbdada7effbc2b97281bfbce0c6df351a3cf88 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Fri, 5 Apr 2024 11:40:56 +0800 Subject: [PATCH 1/2] migration/postcopy: ensure preempt channel is ready before loading states Before loading the guest states, ensure that the preempt channel has been ready to use, as some of the states (e.g. via virtio_load) might trigger page faults that will be handled through the preempt channel. So yield to the main thread in the case that the channel create event hasn't been dispatched. Cc: qemu-stable Fixes: 9358982744 ("migration: Send requested page directly in rp-return thread") Originally-by: Lei Wang Link: https://lore.kernel.org/all/9aa5d1be-7801-40dd-83fd-f7e041ced249@intel.com/T/ Signed-off-by: Lei Wang Signed-off-by: Wei Wang Link: https://lore.kernel.org/r/20240405034056.23933-1-wei.w.wang@intel.com [peterx: add a todo section, add Fixes and copy stable for 8.0+] Signed-off-by: Peter Xu --- migration/savevm.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/migration/savevm.c b/migration/savevm.c index 388d7af7cd..e7c1215671 100644 --- a/migration/savevm.c +++ b/migration/savevm.c @@ -2342,6 +2342,27 @@ static int loadvm_handle_cmd_packaged(MigrationIncomingState *mis) QEMUFile *packf = qemu_file_new_input(QIO_CHANNEL(bioc)); + /* + * Before loading the guest states, ensure that the preempt channel has + * been ready to use, as some of the states (e.g. via virtio_load) might + * trigger page faults that will be handled through the preempt channel. + * So yield to the main thread in the case that the channel create event + * hasn't been dispatched. + * + * TODO: if we can move migration loadvm out of main thread, then we + * won't block main thread from polling the accept() fds. We can drop + * this as a whole when that is done. + */ + do { + if (!migrate_postcopy_preempt() || !qemu_in_coroutine() || + mis->postcopy_qemufile_dst) { + break; + } + + aio_co_schedule(qemu_get_current_aio_context(), qemu_coroutine_self()); + qemu_coroutine_yield(); + } while (1); + ret = qemu_loadvm_state_main(packf, mis); trace_loadvm_handle_cmd_packaged_main(ret); qemu_fclose(packf); From 8e0b21e375f0f6e6dbaeaecc1d52e2220f163e40 Mon Sep 17 00:00:00 2001 From: Avihai Horon Date: Sun, 7 Apr 2024 11:11:25 +0300 Subject: [PATCH 2/2] MAINTAINERS: Adjust migration documentation files Commit 8cb2f8b172e7 ("docs/migration: Create migration/ directory") changed migration documentation file structure but forgot to update the entries in the MAINTAINERS file. Commit 4c6f8a79ae53 ("docs/migration: Split 'dirty limit'") extracted dirty limit documentation to a new file without updating dirty limit section in MAINTAINERS file. Fix the above. Fixes: 8cb2f8b172e7 ("docs/migration: Create migration/ directory") Fixes: 4c6f8a79ae53 ("docs/migration: Split 'dirty limit'") Signed-off-by: Avihai Horon Link: https://lore.kernel.org/r/20240407081125.13951-1-avihaih@nvidia.com Signed-off-by: Peter Xu --- MAINTAINERS | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/MAINTAINERS b/MAINTAINERS index e71183eef9..d3fc2a06e3 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2170,7 +2170,7 @@ S: Supported F: hw/vfio/* F: include/hw/vfio/ F: docs/igd-assign.txt -F: docs/devel/vfio-migration.rst +F: docs/devel/migration/vfio.rst vfio-ccw M: Eric Farman @@ -2231,6 +2231,7 @@ F: qapi/virtio.json F: net/vhost-user.c F: include/hw/virtio/ F: docs/devel/virtio* +F: docs/devel/migration/virtio.rst virtio-balloon M: Michael S. Tsirkin @@ -3422,7 +3423,7 @@ F: migration/ F: scripts/vmstate-static-checker.py F: tests/vmstate-static-checker-data/ F: tests/qtest/migration-test.c -F: docs/devel/migration.rst +F: docs/devel/migration/ F: qapi/migration.json F: tests/migration/ F: util/userfaultfd.c @@ -3442,6 +3443,7 @@ F: include/sysemu/dirtylimit.h F: migration/dirtyrate.c F: migration/dirtyrate.h F: include/sysemu/dirtyrate.h +F: docs/devel/migration/dirty-limit.rst Detached LUKS header M: Hyman Huang