Re: [PATCH v5 00/12] Make RamDiscardManager work with multiple sources & virtio-mem

Hi

On Thu, Jun 4, 2026 at 5:46=E2=80=AFPM Marc-Andr=C3=A9 Lureau
<[email protected]> wrote:
>
> Hi,
>
> This is an attempt to fix the incompatibility of virtio-mem with confiden=
tial
> VMs. The solution implements what was discussed earlier with D. Hildenbra=
nd:
> https://patchwork.ozlabs.org/project/qemu-devel/patch/20250407074939.1865=
[email protected]/#3502238
>
> The first patches are misc cleanups. Then some code refactoring to have s=
plit a
> manager/source. And finally, the manager learns to deal with multiple sou=
rces.
>
> This has been tested together with the Linux kernel series from
> Zhenzhong Duan [1] for TDX guests.
>
> (help fix https://issues.redhat.com/browse/RHEL-131968)

Can the patch 1-11 be queued or are we missing something?
(RFC patch 12 can be dropped for now)

thanks

>
> v5:
> - explain why InterfaceClass in rust binding is not needed after
>   moving RamDiscardSource
> - drop extraneous added blank line
> - replaced a runtime "if (has_rdm)"" with an assert()
> - dropped "RFC: hw/virtio: start virtio-mem guest_memfd regions as
>   shared", in favour of start-private memory approach from "[RFC PATCH
>   0/6] Support virtio-mem memory hotplug in TDX guests" [1]
> - demote "monitor: add 'info ramblock-attributes'" as RFC
> - rebased and collected trailers
>
> v4:
>  - added "system/physmem: make ram_block_discard_range() handle guest_mem=
fd"
>  - added "monitor: add 'info ramblock-attributes' command"
>  - added "RFC: hw/virtio: start virtio-mem guest_memfd regions as shared"
>  - skip calling source in notify_populate (it may not have updated its
>    internal state)
>  - rebased, collected trailer tags
>
> v3: issues found by C=C3=A9dric
>  - fix assertion error on shutdown, due to rcu-defer cleanup
>  - fix API doc warnings
>
> v2:
>  - drop replay_{populated,discarded} from source, suggested by Peter Xu
>  - add extra manager cleanup
>  - add r-b tags for preliminary patches
>
> - Link to v4: https://lore.kernel.org/qemu-devel/20260504-rdm5-v4-0-bdf61=
[email protected]
>
> [1]: https://lore.kernel.org/lkml/20260604093551.1511079-1-zhenzhong.duan=
@intel.com/
>
> ---
> Marc-Andr=C3=A9 Lureau (12):
>       system/memory: split RamDiscardManager into source and manager
>       system/memory: move RamDiscardManager to separate compilation unit
>       system/memory: constify section arguments
>       system/ram-discard-manager: implement replay via is_populated itera=
tion
>       virtio-mem: remove replay_populated/replay_discarded implementation
>       system/ram-discard-manager: drop replay from source interface
>       system/memory: implement RamDiscardManager multi-source aggregation
>       system/physmem: destroy ram block attributes before RCU-deferred re=
claim
>       system/memory: add RamDiscardManager reference counting and cleanup
>       tests: add unit tests for RamDiscardManager multi-source aggregatio=
n
>       system/physmem: make ram_block_discard_range() handle guest_memfd
>       RFC: monitor: add 'info ramblock-attributes' command
>
>  MAINTAINERS                                 |    4 +
>  qapi/machine.json                           |   56 ++
>  include/hw/vfio/vfio-container.h            |    2 +-
>  include/hw/vfio/vfio-cpr.h                  |    2 +-
>  include/hw/virtio/virtio-mem.h              |    3 -
>  include/monitor/hmp.h                       |    1 +
>  include/system/memory.h                     |  279 +-----
>  include/system/ram-discard-manager.h        |  358 ++++++++
>  include/system/ramblock.h                   |    5 +-
>  accel/kvm/kvm-all.c                         |    2 +-
>  hw/core/machine-hmp-cmds.c                  |   32 +
>  hw/vfio/cpr-legacy.c                        |    4 +-
>  hw/vfio/listener.c                          |   10 +-
>  hw/virtio/virtio-mem.c                      |  259 +-----
>  migration/ram.c                             |    6 +-
>  system/memory.c                             |   88 +-
>  system/memory_mapping.c                     |    4 +-
>  system/physmem.c                            |   27 +-
>  system/ram-block-attributes.c               |  328 +++----
>  system/ram-discard-manager.c                |  612 +++++++++++++
>  target/i386/kvm/tdx.c                       |    2 +-
>  tests/unit/test-ram-discard-manager-stubs.c |   48 ++
>  tests/unit/test-ram-discard-manager.c       | 1235 +++++++++++++++++++++=
++++++
>  hmp-commands-info.hx                        |   13 +
>  rust/bindings/system-sys/lib.rs             |    2 +-
>  system/meson.build                          |    1 +
>  system/trace-events                         |    2 +-
>  tests/unit/meson.build                      |    8 +-
>  28 files changed, 2569 insertions(+), 824 deletions(-)
> ---
> base-commit: 405c32d2b18a683ba36301351af75125d9afda08
> change-id: 20260414-rdm5-b6df2366d603
>
> Best regards,
> --
> Marc-Andr=C3=A9 Lureau <[email protected]>
>
>