[v9,0/7] KVM: arm64: Enable ring-based dirty memory tracking

Message

Gavin Shan Nov. 8, 2022, 4:10 a.m. UTC

This series enables the ring-based dirty memory tracking for ARM64.
The feature has been available and enabled on x86 for a while. It
is beneficial when the number of dirty pages is small in a checkpointing
system or live migration scenario. More details can be found from
fb04a1eddb1a ("KVM: X86: Implement ring-based dirty memory tracking").

For PATCH[v9 3/7], Peter's ack-by is kept since the recent changes 
don't fundamentally break what he agreed. However, it would be nice
for Peter to double confirm.

v8: https://lore.kernel.org/kvmarm/[e-mail]/T/#t
v7: https://lore.kernel.org/kvmarm/[e-mail]/
v6: https://lore.kernel.org/kvmarm/[e-mail]/
v5: https://lore.kernel.org/all/[e-mail]/
v4: https://lore.kernel.org/kvmarm/[e-mail]/
v3: https://lore.kernel.org/r/[e-mail]
v2: https://lore.kernel.org/lkml/[e-mail]/T/
v1: https://lore.kernel.org/lkml/[e-mail]

Testing
=======
(1) kvm/selftests/dirty_log_test
(2) Live migration by QEMU (partially)

Changelog
=========
v9:
  * Improved documentation in PATCH[v9 3/7]                     (Marc/Peter)
  * Add helper to check if we have any memslot and lockdep
    assert is added to kvm_use_dirty_bitmap() in PATCH[v9 3/7]  (Sean/Oliver)
  * Drop the helper to return dist->save_its_tables_in_progress
    and move kvm_arch_allow_write_without_running_vcpu() to
    vgic-its.c in PATCH[v9 4/7]                                 (Marc)
v8:
  * Pick review-by and ack-by                                   (Peter/Sean)
  * Drop chunk of code to clear KVM_REQ_DIRTY_RING_SOFT_FULL
    in kvm_dirty_ring_reset(). Add comments to say the event
    will be cleared by the VCPU thread next time when it enters
    the guest. All other changes related to kvm_dirty_ring_reset()
    are dropped in PATCH[v8 1/7].                               (Sean/Peter/Marc)
  * Drop PATCH[v7 3/7] since it has been merged                 (Marc/Oliver)
  * Document the order of DIRTY_RING_{ACQ_REL, WITH_BITMAP},
    add check to ensure no memslots are created when
    DIRTY_RING_WITH_BITMAP is enabled, and add weak function
    kvm_arch_allow_write_without_running_vcpu() in PATCH[v8 3/7] (Oliver)
  * Only keep ourself out of non-running-vcpu radar when vgic/its
    tables are being saved in PATCH[v8 4/7]                      (Marc/Sean)
v7:
  * Cut down #ifdef, avoid using 'container_of()', move the
    dirty-ring check after KVM_REQ_VM_DEAD, add comments
    for kvm_dirty_ring_check_request(), use tab character
    for KVM event definitions in kvm_host.h in PATCH[v7 01]    (Sean)
  * Add PATCH[v7 03] to recheck if the capability has
    been advertised prior to enable RING/RING_ACEL_REL         (Sean)
  * Improve the description about capability RING_WITH_BITMAP,
    rename kvm_dirty_ring_exclusive() to kvm_use_dirty_bitmap()
    in PATCH[v7 04/09]                                         (Peter/Oliver/Sean)
  * Add PATCH[v7 05/09] to improve no-running-vcpu report      (Marc/Sean)
  * Improve commit messages                                    (Sean/Oliver)
v6:
  * Add CONFIG_HAVE_KVM_DIRTY_RING_WITH_BITMAP, for arm64
    to advertise KVM_CAP_DIRTY_RING_WITH_BITMAP in
    PATCH[v6 3/8]                                              (Oliver/Peter)
  * Add helper kvm_dirty_ring_exclusive() to check if
    traditional bitmap-based dirty log tracking is
    exclusive to dirty-ring in PATCH[v6 3/8]                   (Peter)
  * Enable KVM_CAP_DIRTY_RING_WITH_BITMAP in PATCH[v6 5/8]     (Gavin)
v5:
  * Drop empty stub kvm_dirty_ring_check_request()             (Marc/Peter)
  * Add PATCH[v5 3/7] to allow using bitmap, indicated by
    KVM_CAP_DIRTY_LOG_RING_ALLOW_BITMAP                        (Marc/Peter)
v4:
  * Commit log improvement                                     (Marc)
  * Add helper kvm_dirty_ring_check_request()                  (Marc)
  * Drop ifdef for kvm_cpu_dirty_log_size()                    (Marc)
v3:
  * Check KVM_REQ_RING_SOFT_RULL inside kvm_request_pending()  (Peter)
  * Move declaration of kvm_cpu_dirty_log_size()               (test-robot)
v2:
  * Introduce KVM_REQ_RING_SOFT_FULL                           (Marc)
  * Changelog improvement                                      (Marc)
  * Fix dirty_log_test without knowing host page size          (Drew)

Gavin Shan (7):
  KVM: x86: Introduce KVM_REQ_DIRTY_RING_SOFT_FULL
  KVM: Move declaration of kvm_cpu_dirty_log_size() to kvm_dirty_ring.h
  KVM: Support dirty ring in conjunction with bitmap
  KVM: arm64: Enable ring-based dirty memory tracking
  KVM: selftests: Use host page size to map ring buffer in
    dirty_log_test
  KVM: selftests: Clear dirty ring states between two modes in
    dirty_log_test
  KVM: selftests: Automate choosing dirty ring size in dirty_log_test

 Documentation/virt/kvm/api.rst                | 36 ++++++++---
 .../virt/kvm/devices/arm-vgic-its.rst         |  5 +-
 arch/arm64/include/uapi/asm/kvm.h             |  1 +
 arch/arm64/kvm/Kconfig                        |  2 +
 arch/arm64/kvm/arm.c                          |  3 +
 arch/arm64/kvm/vgic/vgic-its.c                | 20 ++++++
 arch/x86/include/asm/kvm_host.h               |  2 -
 arch/x86/kvm/x86.c                            | 15 ++---
 include/kvm/arm_vgic.h                        |  1 +
 include/linux/kvm_dirty_ring.h                | 20 +++---
 include/linux/kvm_host.h                      | 10 +--
 include/uapi/linux/kvm.h                      |  1 +
 tools/testing/selftests/kvm/dirty_log_test.c  | 53 +++++++++++----
 tools/testing/selftests/kvm/lib/kvm_util.c    |  2 +-
 virt/kvm/Kconfig                              |  8 +++
 virt/kvm/dirty_ring.c                         | 44 ++++++++++++-
 virt/kvm/kvm_main.c                           | 64 +++++++++++++++----
 17 files changed, 227 insertions(+), 60 deletions(-)