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67428ee7b7
Sync the new iteration to the guest prior to restarting the vCPU, otherwise it's possible for the vCPU to dirty memory for the next iteration using the current iteration's value. Note, because the guest can be interrupted between the vCPU's load of the iteration and its write to memory, it's still possible for the guest to store the previous iteration to memory as the previous iteration may be cached in a CPU register (which the test accounts for). Note #2, the test's current approach of collecting dirty entries *before* stopping the vCPU also results dirty memory having the previous iteration. E.g. if page is dirtied in the previous iteration, but not the current iteration, the verification phase will observe the previous iteration's value in memory. That wart will be remedied in the near future, at which point synchronizing the iteration before restarting the vCPU will guarantee the only way for verification to observe stale iterations is due to the CPU register caching case, or due to a dirty entry being collected before the store retires. Link: https://lore.kernel.org/r/20250111003004.1235645-3-seanjc@google.com Signed-off-by: Sean Christopherson <seanjc@google.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.