| From: |
| Jack Thomson <jackabt.amazon-AT-gmail.com> |
| To: |
| maz-AT-kernel.org, oliver.upton-AT-linux.dev, pbonzini-AT-redhat.com |
| Subject: |
| [PATCH v2 0/4] KVM ARM64 pre_fault_memory |
| Date: |
| Mon, 13 Oct 2025 16:14:57 +0100 |
| Message-ID: |
| <20251013151502.6679-1-jackabt.amazon@gmail.com> |
| Cc: |
| joey.gouly-AT-arm.com, suzuki.poulose-AT-arm.com, yuzenghui-AT-huawei.com, catalin.marinas-AT-arm.com, will-AT-kernel.org, shuah-AT-kernel.org, linux-arm-kernel-AT-lists.infradead.org, kvmarm-AT-lists.linux.dev, linux-kernel-AT-vger.kernel.org, linux-kselftest-AT-vger.kernel.org, isaku.yamahata-AT-intel.com, roypat-AT-amazon.co.uk, kalyazin-AT-amazon.co.uk, jackabt-AT-amazon.com |
| Archive-link: |
| Article |
From: Jack Thomson <jackabt@amazon.com>
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 fixes an issue with unaligned mmap allocations
in the selftests.
- The third 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.
=== Changes Since v1 [2] ===
Addressing feedback from Oliver:
- No pre-fault flag is passed to user_mem_abort() or gmem_abort() now
aborts are synthesized.
- Remove retry loop from kvm_arch_vcpu_pre_fault_memory()
[1]: https://lore.kernel.org/kvm/20240710174031.312055-1-pbonz...
[2]: https://lore.kernel.org/all/20250911134648.58945-1-jackab...
Jack Thomson (4):
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
Documentation/virt/kvm/api.rst | 3 +-
arch/arm64/kvm/Kconfig | 1 +
arch/arm64/kvm/arm.c | 1 +
arch/arm64/kvm/mmu.c | 73 +++++++++++-
tools/testing/selftests/kvm/Makefile.kvm | 1 +
tools/testing/selftests/kvm/lib/kvm_util.c | 12 +-
.../selftests/kvm/pre_fault_memory_test.c | 110 +++++++++++++-----
7 files changed, 163 insertions(+), 38 deletions(-)
base-commit: 42188667be387867d2bf763d028654cbad046f7b
--
2.43.0
