From: Jack Thomson <[email protected]> This patch series adds ARM64 support for the KVM_PRE_FAULT_MEMORY feature, which was previously only available on x86 [1]. This allows us to reduce the number of stage-2 faults during execution. This is of benefit in post-copy migration scenarios, particularly in memory intensive applications, where we are experiencing high latencies due to the stage-2 faults.
Patch Overview: - The first patch adds support for the KVM_PRE_FAULT_MEMORY ioctl on arm64. - The second patch updates the pre_fault_memory_test to support arm64. - The last patch extends the pre_fault_memory_test to cover different vm memory backings. With regards to the additional parameter to `user_mem_abort`, noted in the v3 review, would you like this to be fixed in this series or would a follow-up series be ok? I also found a series from Sean which looks to address this [2]. === Changes Since v3 [3] === - Updated to now return -EOPNOTSUPP for pKVM. Previously this was not checked. - When running a nested guest, properly resolve the L2 IPA to L1 IPA before pre faulting. - Refactoring, page_size is now unsigned and ordered definitions at top of pre_fault function. Thanks Marc for your review === Changes Since v2 [4] === - Update fault info synthesize value. Thanks Suzuki - Remove change to selftests for unaligned mmap allocations. Thanks Sean [1]: https://lore.kernel.org/kvm/[email protected] [2]: https://lore.kernel.org/linux-arm-kernel/[email protected]/ [3]: https://lore.kernel.org/linux-arm-kernel/[email protected] [4]: https://lore.kernel.org/linux-arm-kernel/[email protected] Jack Thomson (3): KVM: arm64: Add pre_fault_memory implementation KVM: selftests: Enable pre_fault_memory_test for arm64 KVM: selftests: Add option for different backing in pre-fault tests Documentation/virt/kvm/api.rst | 3 +- arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/mmu.c | 79 +++++++++++- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/pre_fault_memory_test.c | 115 ++++++++++++++---- 6 files changed, 169 insertions(+), 31 deletions(-) base-commit: 3611ca7c12b740e250d83f8bbe3554b740c503b0 -- 2.43.0
