From: Nikolay Borisov <nik.borisov@suse.com>
To: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
x86@kernel.org, David Kaplan <david.kaplan@amd.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
Asit Mallick <asit.k.mallick@intel.com>,
Tao Zhang <tao1.zhang@intel.com>
Subject: Re: [PATCH v6 7/9] x86/vmscape: Deploy BHB clearing mitigation
Date: Thu, 11 Dec 2025 16:26:27 +0200 [thread overview]
Message-ID: <fbe2eaba-811c-465e-9d99-20d0f0fd3d97@suse.com> (raw)
In-Reply-To: <20251201-vmscape-bhb-v6-7-d610dd515714@linux.intel.com>
On 2.12.25 г. 8:20 ч., Pawan Gupta wrote:
> IBPB mitigation for VMSCAPE is an overkill on CPUs that are only affected
> by the BHI variant of VMSCAPE. On such CPUs, eIBRS already provides
> indirect branch isolation between guest and host userspace. However, branch
> history from guest may also influence the indirect branches in host
> userspace.
>
> To mitigate the BHI aspect, use clear_bhb_loop().
>
> Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>
next prev parent reply other threads:[~2025-12-11 14:26 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-02 6:18 [PATCH v6 0/9] VMSCAPE optimization for BHI variant Pawan Gupta
2025-12-02 6:18 ` [PATCH v6 1/9] x86/bhi: x86/vmscape: Move LFENCE out of clear_bhb_loop() Pawan Gupta
2026-01-01 12:51 ` Borislav Petkov
2026-01-06 4:29 ` Pawan Gupta
2025-12-02 6:19 ` [PATCH v6 2/9] x86/bhi: Make clear_bhb_loop() effective on newer CPUs Pawan Gupta
2025-12-10 12:31 ` Nikolay Borisov
2025-12-10 13:35 ` David Laight
2025-12-10 15:42 ` Nikolay Borisov
2025-12-14 18:38 ` Pawan Gupta
2025-12-14 19:02 ` David Laight
2025-12-15 18:01 ` Pawan Gupta
2025-12-15 21:05 ` David Laight
2025-12-14 17:16 ` Pawan Gupta
2026-01-24 19:34 ` Borislav Petkov
2026-03-05 0:41 ` Pawan Gupta
2025-12-02 6:19 ` [PATCH v6 3/9] x86/vmscape: Rename x86_ibpb_exit_to_user to x86_predictor_flush_exit_to_user Pawan Gupta
2025-12-02 6:19 ` [PATCH v6 4/9] x86/vmscape: Move mitigation selection to a switch() Pawan Gupta
2025-12-10 16:15 ` Nikolay Borisov
2025-12-02 6:19 ` [PATCH v6 5/9] x86/vmscape: Use write_ibpb() instead of indirect_branch_prediction_barrier() Pawan Gupta
2025-12-02 6:20 ` [PATCH v6 6/9] x86/vmscape: Use static_call() for predictor flush Pawan Gupta
2025-12-11 10:06 ` Nikolay Borisov
2025-12-11 10:50 ` Peter Zijlstra
2025-12-14 18:45 ` Pawan Gupta
2025-12-02 6:20 ` [PATCH v6 7/9] x86/vmscape: Deploy BHB clearing mitigation Pawan Gupta
2025-12-11 14:26 ` Nikolay Borisov [this message]
2025-12-02 6:20 ` [PATCH v6 8/9] x86/vmscape: Fix conflicting attack-vector controls with =force Pawan Gupta
2025-12-02 6:21 ` [PATCH v6 9/9] x86/vmscape: Add cmdline vmscape=on to override attack vector controls Pawan Gupta
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