[v1,0/5] Support the FEAT_HDBSS introduced in Armv9.5

Message

Zhenyu Ye March 11, 2025, 4:03 a.m. UTC

From: eillon <[e-mail]>

This series of patches add support to the Hardware Dirty state tracking
Structure(HDBSS) feature, which is introduced by the ARM architecture
in the DDI0601(ID121123) version.

The HDBSS feature is an extension to the architecture that enhances
tracking translation table descriptors' dirty state, identified as
FEAT_HDBSS.  The goal of this feature is to reduce the cost of surveying
for dirtied granules, with minimal effect on recording when a granule
has been dirtied.

The purpose of this feature is to make the execution overhead of live
migration lower to both the guest and the host, compared to existing
approaches (write-protect or search stage 2 tables).

After these patches, users(such as qemu) can use the 
KVM_CAP_ARM_HW_DIRTY_STATE_TRACK ioctl to enable or disable the HDBSS
feature before and after the live migration.

See patches for details, Thanks.

eillon (5):
  arm64/sysreg: add HDBSS related register information
  arm64/kvm: support set the DBM attr during memory abort
  arm64/kvm: using ioctl to enable/disable the HDBSS feature
  arm64/kvm: support to handle the HDBSSF event
  arm64/config: add config to control whether enable HDBSS feature

 arch/arm64/Kconfig                    | 19 +++++++
 arch/arm64/Makefile                   |  4 +-
 arch/arm64/include/asm/cpufeature.h   | 15 +++++
 arch/arm64/include/asm/esr.h          |  2 +
 arch/arm64/include/asm/kvm_arm.h      |  1 +
 arch/arm64/include/asm/kvm_host.h     |  6 ++
 arch/arm64/include/asm/kvm_mmu.h      | 12 ++++
 arch/arm64/include/asm/kvm_pgtable.h  |  3 +
 arch/arm64/include/asm/sysreg.h       | 16 ++++++
 arch/arm64/kvm/arm.c                  | 80 +++++++++++++++++++++++++++
 arch/arm64/kvm/handle_exit.c          | 47 ++++++++++++++++
 arch/arm64/kvm/hyp/pgtable.c          |  6 ++
 arch/arm64/kvm/hyp/vhe/switch.c       |  1 +
 arch/arm64/kvm/mmu.c                  | 10 ++++
 arch/arm64/kvm/reset.c                |  7 +++
 arch/arm64/tools/sysreg               | 28 ++++++++++
 include/linux/kvm_host.h              |  1 +
 include/uapi/linux/kvm.h              |  1 +
 tools/arch/arm64/include/asm/sysreg.h |  4 ++
 tools/include/uapi/linux/kvm.h        |  1 +
 20 files changed, 263 insertions(+), 1 deletion(-)