selftests: KVM: Handle compiler optimizations in ucall

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The selftests, when built with newer versions of clang, is found
to have over optimized guests' ucall() function, and eliminating
the stores for uc.cmd (perhaps due to no immediate readers). This
resulted in the userspace side always reading a value of '0', and
causing multiple test failures.

As a result, prevent the compiler from optimizing the stores in
ucall() with WRITE_ONCE().

Suggested-by: Ricardo Koller <ricarkol@google.com>
Suggested-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Message-Id: <20220615185706.1099208-1-rananta@google.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

...

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Raghavendra Rao Ananta 2022-06-15 18:57:06 +00:00 • committed by Paolo Bonzini

parent 933b5f9f98

commit 9e2f6498ef

1 changed files with 4 additions and 5 deletions

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tools/testing/selftests/kvm/lib/aarch64/ucall.c

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