https://github.com/torvalds/linux
Revision 6336a810db5c7e8e48b55b12fbb5e9cbd36a3d19 authored by Emanuele Giuseppe Esposito on 26 September 2022, 08:29:23 UTC, committed by Paolo Bonzini on 30 September 2022, 10:38:00 UTC
Page_idle uses {ptep/pmdp}_clear_young_notify which in turn calls
the mmu notifier callback ->clear_young(), which purposefully
does not flush the TLB.
When running the test in a nested guest, point 1. of the test
doc header is violated, because KVM TLB is unbounded by size
and since no flush is forced, KVM does not update the sptes
accessed/idle bits resulting in guest assertion failure.
More precisely, only the first ACCESS_WRITE in run_test() actually
makes visible changes, because sptes are created and the accessed
bit is set to 1 (or idle bit is 0). Then the first mark_memory_idle()
passes since access bit is still one, and sets all pages as idle
(or not accessed). When the next write is performed, the update
is not flushed therefore idle is still 1 and next mark_memory_idle()
fails.
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220926082923.299554-1-eesposit@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
1 parent 0f816e0
Tip revision: 6336a810db5c7e8e48b55b12fbb5e9cbd36a3d19 authored by Emanuele Giuseppe Esposito on 26 September 2022, 08:29:23 UTC
KVM: selftests: replace assertion with warning in access_tracking_perf_test
KVM: selftests: replace assertion with warning in access_tracking_perf_test
Tip revision: 6336a81
| File | Mode | Size |
|---|---|---|
| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | -rw-r--r-- | 19.9 KB |
| .cocciconfig | -rw-r--r-- | 59 bytes |
| .get_maintainer.ignore | -rw-r--r-- | 151 bytes |
| .gitattributes | -rw-r--r-- | 62 bytes |
| .gitignore | -rw-r--r-- | 1.9 KB |
| .mailmap | -rw-r--r-- | 23.7 KB |
| COPYING | -rw-r--r-- | 496 bytes |
| CREDITS | -rw-r--r-- | 99.1 KB |
| Kbuild | -rw-r--r-- | 1.3 KB |
| Kconfig | -rw-r--r-- | 555 bytes |
| MAINTAINERS | -rw-r--r-- | 664.6 KB |
| Makefile | -rw-r--r-- | 64.4 KB |
| README | -rw-r--r-- | 727 bytes |
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