From: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
To: x86@kernel.org, Nikolay Borisov <nik.borisov@suse.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
David Kaplan <david.kaplan@amd.com>,
Sean Christopherson <seanjc@google.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
KP Singh <kpsingh@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
David Laight <david.laight.linux@gmail.com>,
Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@kernel.org>, Ingo Molnar <mingo@redhat.com>,
David Ahern <dsahern@kernel.org>,
Martin KaFai Lau <martin.lau@linux.dev>,
Eduard Zingerman <eddyz87@gmail.com>, Song Liu <song@kernel.org>,
Yonghong Song <yonghong.song@linux.dev>,
John Fastabend <john.fastabend@gmail.com>,
Stanislav Fomichev <sdf@fomichev.me>, Hao Luo <haoluo@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jonathan Corbet <corbet@lwn.net>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Asit Mallick <asit.k.mallick@intel.com>,
Tao Zhang <tao1.zhang@intel.com>,
bpf@vger.kernel.org, netdev@vger.kernel.org,
linux-doc@vger.kernel.org
Subject: [PATCH v7 06/10] x86/vmscape: Use write_ibpb() instead of indirect_branch_prediction_barrier()
Date: Thu, 19 Mar 2026 08:41:39 -0700 [thread overview]
Message-ID: <20260319-vmscape-bhb-v7-6-b76a777a98af@linux.intel.com> (raw)
In-Reply-To: <20260319-vmscape-bhb-v7-0-b76a777a98af@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 <dave.hansen@linux.intel.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
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 c45858db16c9..78b143673ca7 100644
--- a/arch/x86/include/asm/entry-common.h
+++ b/arch/x86/include/asm/entry-common.h
@@ -97,7 +97,7 @@ 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
next prev parent reply other threads:[~2026-03-19 15:41 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-19 15:40 [PATCH v7 00/10] VMSCAPE optimization for BHI variant Pawan Gupta
2026-03-19 15:40 ` [PATCH v7 01/10] x86/bhi: x86/vmscape: Move LFENCE out of clear_bhb_loop() Pawan Gupta
2026-03-19 15:40 ` [PATCH v7 02/10] x86/bhi: Make clear_bhb_loop() effective on newer CPUs Pawan Gupta
2026-03-19 15:40 ` [PATCH v7 03/10] x86/bhi: Rename clear_bhb_loop() to clear_bhb_loop_nofence() Pawan Gupta
2026-03-23 14:44 ` Nikolay Borisov
2026-03-23 17:07 ` Pawan Gupta
2026-03-19 15:41 ` [PATCH v7 04/10] x86/vmscape: Rename x86_ibpb_exit_to_user to x86_predictor_flush_exit_to_user Pawan Gupta
2026-03-19 15:41 ` [PATCH v7 05/10] x86/vmscape: Move mitigation selection to a switch() Pawan Gupta
2026-03-19 15:41 ` Pawan Gupta [this message]
2026-03-19 15:41 ` [PATCH v7 07/10] x86/vmscape: Use static_call() for predictor flush Pawan Gupta
2026-03-19 16:56 ` bot+bpf-ci
2026-03-19 18:05 ` Pawan Gupta
2026-03-19 20:58 ` Peter Zijlstra
2026-03-19 21:34 ` Pawan Gupta
2026-03-19 21:44 ` Peter Zijlstra
2026-03-19 22:06 ` Pawan Gupta
2026-03-20 6:22 ` Pawan Gupta
2026-03-20 9:03 ` Peter Zijlstra
2026-03-20 11:31 ` Borislav Petkov
2026-03-20 18:23 ` Pawan Gupta
2026-03-24 20:00 ` Borislav Petkov
2026-03-24 20:14 ` Pawan Gupta
2026-03-19 15:42 ` [PATCH v7 08/10] x86/vmscape: Deploy BHB clearing mitigation Pawan Gupta
2026-03-19 15:42 ` [PATCH v7 09/10] x86/vmscape: Fix conflicting attack-vector controls with =force Pawan Gupta
2026-03-19 15:42 ` [PATCH v7 10/10] x86/vmscape: Add cmdline vmscape=on to override attack vector controls Pawan Gupta
2026-03-19 16:40 ` bot+bpf-ci
2026-03-19 17:57 ` Pawan Gupta
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