[PATCH v12 06/12] x86/vmscape: Use write_ibpb() instead of indirect_branch_prediction_barrier()
From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Date: 2026-06-23 17:34:11
Also in:
bpf, kvm, linux-doc, lkml
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
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 <dave.hansen@linux.intel.com> Tested-by: Jon Kohler <redacted> Reviewed-by: Nikolay Borisov <redacted> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com> --- 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