x86/bugs: Skip RSB fill at VMEXIT

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commit 0fad287864 upstream.

entry_ibpb() is designed to follow Intel's IBPB specification regardless
of CPU. This includes invalidating RSB entries.

Hence, if IBPB on VMEXIT has been selected, entry_ibpb() as part of the
RET untraining in the VMEXIT path will take care of all BTB and RSB
clearing so there's no need to explicitly fill the RSB anymore.

  [ bp: Massage commit message. ]

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Johannes Wikner <kwikner@ethz.ch>
Cc: <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Johannes Wikner 2024-10-08 12:36:30 +02:00 • committed by Greg Kroah-Hartman

parent e6f0abe6f1

commit e4f2043985

1 changed files with 15 additions and 0 deletions

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arch/x86/kernel/cpu/bugs.c

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