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Peter Anvin" , Josh Poimboeuf , David Kaplan , Sean Christopherson , Borislav Petkov , Dave Hansen , Peter Zijlstra , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , KP Singh , Jiri Olsa , "David S. Miller" , David Laight , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , David Ahern , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , John Fastabend , Stanislav Fomichev , Hao Luo , Paolo Bonzini , Jonathan Corbet , Jason Baron , Alice Ryhl , Steven Rostedt , Ard Biesheuvel , Shuah Khan Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Asit Mallick , Tao Zhang , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org Subject: [PATCH v12 06/12] x86/vmscape: Use write_ibpb() instead of indirect_branch_prediction_barrier() Message-ID: <20260622-vmscape-bhb-v12-6-76cbda0ae3e5@linux.intel.com> X-Mailer: b4 0.16-dev References: <20260622-vmscape-bhb-v12-0-76cbda0ae3e5@linux.intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260622-vmscape-bhb-v12-0-76cbda0ae3e5@linux.intel.com> indirect_branch_prediction_barrier() is a wrapper to write_ibpb(), which also checks if the CPU supports IBPB. For VMSCAPE, call to indirect_branch_prediction_barrier() is only possible when CPU supports IBPB. Simply call write_ibpb() directly to avoid unnecessary alternative patching. Suggested-by: Dave Hansen Tested-by: Jon Kohler Reviewed-by: Nikolay Borisov Signed-off-by: Pawan Gupta --- arch/x86/include/asm/entry-common.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/include/asm/entry-common.h b/arch/x86/include/asm/entry-common.h index e2b985929083..3be6d4c356ed 100644 --- a/arch/x86/include/asm/entry-common.h +++ b/arch/x86/include/asm/entry-common.h @@ -85,7 +85,7 @@ static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs, /* Avoid unnecessary reads of 'x86_predictor_flush_exit_to_user' */ if (cpu_feature_enabled(X86_FEATURE_IBPB_EXIT_TO_USER) && this_cpu_read(x86_predictor_flush_exit_to_user)) { - indirect_branch_prediction_barrier(); + write_ibpb(); this_cpu_write(x86_predictor_flush_exit_to_user, false); } } -- 2.34.1