linux/Documentation/admin-guide/hw-vuln
Pawan Gupta ec9404e40e x86/bhi: Add BHI mitigation knob
Branch history clearing software sequences and hardware control
BHI_DIS_S were defined to mitigate Branch History Injection (BHI).

Add cmdline spectre_bhi={on|off|auto} to control BHI mitigation:

 auto - Deploy the hardware mitigation BHI_DIS_S, if available.
 on   - Deploy the hardware mitigation BHI_DIS_S, if available,
        otherwise deploy the software sequence at syscall entry and
	VMexit.
 off  - Turn off BHI mitigation.

The default is auto mode which does not deploy the software sequence
mitigation.  This is because of the hardening done in the syscall
dispatch path, which is the likely target of BHI.

Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org>
2024-04-08 19:27:05 +02:00
..
core-scheduling.rst uapi/linux/prctl: provide macro definitions for the PR_SCHED_CORE type argument 2021-09-29 13:00:05 +02:00
cross-thread-rsb.rst Documentation/hw-vuln: Fix rST warning 2023-02-15 07:24:23 -05:00
gather_data_sampling.rst Documentation/x86: Fix backwards on/off logic about YMM support 2023-08-01 15:28:24 -07:00
index.rst Documentation/hw-vuln: Add documentation for RFDS 2024-03-11 13:13:46 -07:00
l1d_flush.rst Documentation: Add L1D flushing Documentation 2021-07-28 11:42:25 +02:00
l1tf.rst docs: add IRQ documentation at the core-api book 2020-05-15 12:00:56 -06:00
mds.rst docs/hw-vuln: Update desc of best effort mode 2023-10-10 13:35:55 -06:00
multihit.rst x86/bugs/multihit: Fix mitigation reporting when VMX is not in use 2020-08-07 01:32:00 +02:00
processor_mmio_stale_data.rst docs/hw-vuln: Update desc of best effort mode 2023-10-10 13:35:55 -06:00
reg-file-data-sampling.rst Documentation/hw-vuln: Add documentation for RFDS 2024-03-11 13:13:46 -07:00
special-register-buffer-data-sampling.rst docs: admin-guide: hw-vuln: avoid using ReST :doc:foo markup 2021-06-17 13:24:36 -06:00
spectre.rst x86/bhi: Add BHI mitigation knob 2024-04-08 19:27:05 +02:00
srso.rst x86/srso: Fix vulnerability reporting for missing microcode 2023-10-20 11:46:09 +02:00
tsx_async_abort.rst docs/hw-vuln: Update desc of best effort mode 2023-10-10 13:35:55 -06:00