[SH] use UFFDIO_COPY to resolve UFFD faults#5734
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kalyazin wants to merge 4 commits intofirecracker-microvm:feature/secret-hidingfrom
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[SH] use UFFDIO_COPY to resolve UFFD faults#5734kalyazin wants to merge 4 commits intofirecracker-microvm:feature/secret-hidingfrom
kalyazin wants to merge 4 commits intofirecracker-microvm:feature/secret-hidingfrom
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This is because guest_memfd now supports both modes. We still need minor handling in case prepopulation logic adds a page in the page cache and the VMM accesses it later via user mappings. Signed-off-by: Nikita Kalyazin <kalyazin@amazon.com>
Now that guest_memfd has support for major faults, we can resolve all on-demand user mapping faults with UFFDIO_COPY. Remove the code that uses memcpy memory population. Signed-off-by: Nikita Kalyazin <kalyazin@amazon.com>
With adding major fault support in guest_memfd, when a major fault is generated, no page is added in the page cache by the kernel. It means that proactive population with write() will succeed for the entire region but possibly one page (kvmclock on x86). We just need to call UFFDIO_CONTINUE in response to such a major fault because we already populated the faulting page via write() earlier. Signed-off-by: Nikita Kalyazin <kalyazin@amazon.com>
This is because when upgrading the guest kernel from 6.1.155 to 6.1.163, /sys/devices/system/cpu/cpu?/cache/* files disappeared. Signed-off-by: Nikita Kalyazin <kalyazin@amazon.com>
kalyazin
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Additional details and impacted files@@ Coverage Diff @@
## feature/secret-hiding #5734 +/- ##
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- Coverage 82.04% 82.00% -0.04%
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Files 277 277
Lines 30092 30093 +1
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- Hits 24688 24677 -11
- Misses 5404 5416 +12
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Changes
RegisterMode::MISSINGin FirecrackerUFFDIO_COPYtest_cache_topologytemporarily on ARM due to changes in guest cache topology sysfs filesReason
UFFDIO_CONTINUEtoUFFDIO_COPYfor handling major faultsLicense Acceptance
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CONTRIBUTING.md.PR Checklist
tools/devtool checkbuild --allto verify that the PR passesbuild checks on all supported architectures.
tools/devtool checkstyleto verify that the PR passes theautomated style checks.
how they are solving the problem in a clear and encompassing way.
in the PR.
CHANGELOG.md.Runbook for Firecracker API changes.
integration tests.
TODO.rust-vmm.