From: Jack Thomson <[email protected]> Overview:
This patch series adds ARM64 support for the KVM_PRE_FAULT_MEMORY feature, which was previously only available on x86 [1]. This allows a reduction in the number of stage-2 faults during execution. This is beneficial in post-copy migration scenarios, particularly in memory intensive applications, where high latencies are experienced due to the stage-2 faults when pre-populating memory via UFFD / memcpy. Patch Overview: - The first patch is a preparatory refactor. - The second patch is adding a page walk flag for pre-faulting. - The third patch adds support for the KVM_PRE_FAULT_MEMORY ioctl on arm64. - The fourth patch fixes an issue with unaligned mmap allocations in the selftests. - The fifth 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. [1]: https://lore.kernel.org/kvm/[email protected] Jack Thomson (6): KVM: arm64: Add __gmem_abort and __user_mem_abort KVM: arm64: Add KVM_PGTABLE_WALK_PRE_FAULT walk flag KVM: arm64: Add pre_fault_memory implementation KVM: selftests: Fix unaligned mmap allocations KVM: selftests: Enable pre_fault_memory_test for arm64 KVM: selftests: Add option for different backing in pre-fault tests arch/arm64/include/asm/kvm_pgtable.h | 3 + arch/arm64/kvm/Kconfig | 1 + arch/arm64/kvm/arm.c | 1 + arch/arm64/kvm/hyp/pgtable.c | 6 +- arch/arm64/kvm/mmu.c | 97 +++++++++++++-- tools/testing/selftests/kvm/Makefile.kvm | 1 + tools/testing/selftests/kvm/lib/kvm_util.c | 12 +- .../selftests/kvm/pre_fault_memory_test.c | 110 +++++++++++++----- 8 files changed, 186 insertions(+), 45 deletions(-) base-commit: 42188667be387867d2bf763d028654cbad046f7b -- 2.43.0
