* David Hildenbrand (da...@redhat.com) wrote: > v4 has been floating around for a while. Let's see if we can find someone > to merge this; or at least give some more feedback ... all patches have > at least one RB. > > > I realized that resizing RAM blocks while the guest is being migrated > (precopy: resize while still running on the source, postcopy: resize > while already running on the target) is buggy. In case of precopy, we > can simply cancel migration. Postcopy handling is more involved. Resizing > can currently happen during a guest reboot, triggered by ACPI rebuilds. > > Along with the fixes, some cleanups.
Queued > > -------------------------------------------------------------------------- > > Example to highlight one part of the problem: > > 1. Start a paused VM (where a ramblock resize will trigger when booting): > sudo build/qemu-system-x86_64 \ > --enable-kvm \ > -S \ > -machine q35,nvdimm=on \ > -smp 1 \ > -cpu host \ > -m size=20G,slots=8,maxmem=22G \ > -object memory-backend-file,id=mem0,mem-path=/tmp/nvdimm,size=256M \ > -device nvdimm,label-size=131072,memdev=mem0,id=nvdimm0,slot=1 \ > -nodefaults \ > -chardev stdio,nosignal,id=serial \ > -device isa-serial,chardev=serial \ > -chardev socket,id=monitor,path=/var/tmp/monitor,server,nowait \ > -mon chardev=monitor,mode=readline \ > -device vmgenid \ > -device intel-iommu \ > -nographic > > 2. Starting precopy and then starting the VM to trigger resizing during > precopy: > QEMU 5.2.95 monitor - type 'help' for more information > (qemu) migrate -d "exec:gzip -c > STATEFILE.gz" > QEMU 5.2.95 monitor - type 'help' for more information > (qemu) cont > > 3a. Before this series, migration never completes: > QEMU 5.2.95 monitor - type 'help' for more information > (qemu) info migrate > globals: > store-global-state: on > only-migratable: off > send-configuration: on > send-section-footer: on > decompress-error-check: on > clear-bitmap-shift: 18 > Migration status: active > total time: 43826 ms > expected downtime: 300 ms > setup: 5 ms > transferred ram: 65981 kbytes > throughput: 8.27 mbps > remaining ram: 18446744073709551612 kbytes > total ram: 21234188 kbytes > duplicate: 5308454 pages > skipped: 0 pages > normal: 93 pages > normal bytes: 372 kbytes > dirty sync count: 1 > page size: 4 kbytes > multifd bytes: 0 kbytes > pages-per-second: 0 > > 4. With this change, migration is properly aborted: > (qemu) info migrate > globals: > store-global-state: on > only-migratable: off > send-configuration: on > send-section-footer: on > decompress-error-check: on > clear-bitmap-shift: 18 > Migration status: cancelled > total time: 0 ms > > -------------------------------------------------------------------------- > > Cc: Eduardo Habkost <ehabk...@redhat.com> > Cc: Marcel Apfelbaum <marcel.apfelb...@gmail.com> > Cc: "Michael S. Tsirkin" <m...@redhat.com> > Cc: Paolo Bonzini <pbonz...@redhat.com> > Cc: Richard Henderson <richard.hender...@linaro.org> > Cc: Juan Quintela <quint...@redhat.com> > Cc: "Dr. David Alan Gilbert" <dgilb...@redhat.com> > Cc: Peter Xu <pet...@redhat.com> > Cc: Alex Williamson <alex.william...@redhat.com> > > v4 -> v5: > - Rephrased some patch descriptions > - Dropped some patches to reduce the footprint > -- "stubs/ram-block: Remove stubs that are no longer needed" > -- "migration/ram: Tolerate partially changed mappings in postcopy code" > - Removed as already upstream now > -- "migration/ram: Consolidate variable reset after placement in > ram_load_postcopy()" > > v3 -> v4: > - Rebased and retested > - Added RBs > > v2 -> v3: > - Rebased on current master > - Added RBs > - "migration/ram: Tolerate partially changed mappings in postcopy code" > -- Extended the comment for the uffdio unregister part. > > v1 -> v2: > - "util: vfio-helpers: Factor out and fix processing of existing ram > blocks" > -- Stringify error > - "migraton/ram: Handle RAM block resizes during precopy" > -- Simplified check if we're migrating on the source > - "exec: Relax range check in ram_block_discard_range()" > -- Added to make discard during resizes actually work > - "migration/ram: Discard new RAM when growing RAM blocks after > ram_postcopy_incoming_init()" > -- Better checks if in the right postcopy mode. > -- Better patch subject/description/comments > - "migration/ram: Handle RAM block resizes during postcopy" > -- Better comments > -- Adapt to changed postcopy checks > - "migrate/ram: Get rid of "place_source" in ram_load_postcopy()" > -- Dropped, as broken > - "migration/ram: Tolerate partially changed mappings in postcopy code" > -- Better comment / description. Clarify that no implicit wakeup will > happen > -- Warn on EINVAL (older kernels) > -- Wake up any waiter explicitly > > David Hildenbrand (10): > util: vfio-helpers: Factor out and fix processing of existing ram > blocks > numa: Teach ram block notifiers about resizeable ram blocks > numa: Make all callbacks of ram block notifiers optional > migration/ram: Handle RAM block resizes during precopy > exec: Relax range check in ram_block_discard_range() > migration/ram: Discard RAM when growing RAM blocks after > ram_postcopy_incoming_init() > migration/ram: Simplify host page handling in ram_load_postcopy() > migration/ram: Handle RAM block resizes during postcopy > migration/multifd: Print used_length of memory block > migration/ram: Use offset_in_ramblock() in range checks > > hw/core/numa.c | 41 +++++++++-- > hw/i386/xen/xen-mapcache.c | 7 +- > include/exec/cpu-common.h | 1 + > include/exec/memory.h | 10 +-- > include/exec/ramblock.h | 10 +++ > include/exec/ramlist.h | 13 ++-- > migration/migration.c | 9 ++- > migration/migration.h | 1 + > migration/multifd.c | 2 +- > migration/postcopy-ram.c | 15 ++++- > migration/ram.c | 135 +++++++++++++++++++++++++++++-------- > softmmu/physmem.c | 26 +++++-- > target/i386/hax/hax-mem.c | 5 +- > target/i386/sev.c | 18 ++--- > util/vfio-helpers.c | 41 ++++------- > 15 files changed, 241 insertions(+), 93 deletions(-) > > -- > 2.30.2 > > -- Dr. David Alan Gilbert / dgilb...@redhat.com / Manchester, UK