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Wed, 19 Nov 2025 07:49:24 -0800 (PST) Received: from f4d4888f22f2.ant.amazon.com.com ([15.248.3.91]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-42c9628ebacsm25969755f8f.30.2025.11.19.07.49.23 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 19 Nov 2025 07:49:23 -0800 (PST) From: Jack Thomson To: maz@kernel.org, oliver.upton@linux.dev, pbonzini@redhat.com Cc: joey.gouly@arm.com, suzuki.poulose@arm.com, yuzenghui@huawei.com, catalin.marinas@arm.com, will@kernel.org, shuah@kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, isaku.yamahata@intel.com, xmarcalx@amazon.co.uk, kalyazin@amazon.co.uk, jackabt@amazon.com Subject: [PATCH v3 0/3] KVM ARM64 pre_fault_memory Date: Wed, 19 Nov 2025 15:49:07 +0000 Message-ID: <20251119154910.97716-1-jackabt.amazon@gmail.com> X-Mailer: git-send-email 2.50.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Jack Thomson 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. === Changes Since v2 [2] === - Update fault info synthesize value. Thanks Suzuki - Remove change to selftests for unaligned mmap allocations. Thanks Sean [1]: https://lore.kernel.org/kvm/20240710174031.312055-1-pbonzini@redhat.com [2]: https://lore.kernel.org/linux-arm-kernel/20251013151502.6679-1-jackabt.amazon@gmail.com 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 | 73 +++++++++++- tools/testing/selftests/kvm/Makefile.kvm | 1 + .../selftests/kvm/pre_fault_memory_test.c | 110 ++++++++++++++---- 6 files changed, 159 insertions(+), 30 deletions(-) base-commit: 8a4821412cf2c1429fffa07c012dd150f2edf78c -- 2.43.0