x86/bhi: Define SPEC_CTRL_BHI_DIS_S

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commit 0f4a837615 upstream.

Newer processors supports a hardware control BHI_DIS_S to mitigate
Branch History Injection (BHI). Setting BHI_DIS_S protects the kernel
from userspace BHI attacks without having to manually overwrite the
branch history.

Define MSR_SPEC_CTRL bit BHI_DIS_S and its enumeration CPUID.BHI_CTRL.
Mitigation is enabled later.

Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
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>
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Daniel Sneddon 2024-03-13 09:47:57 -07:00 • committed by Greg Kroah-Hartman

parent 07dbb10f15

commit 29c50bb6fb

4 changed files with 8 additions and 2 deletions

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1

arch/x86/include/asm/cpufeatures.h

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arch/x86/include/asm/msr-index.h

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arch/x86/kernel/cpu/scattered.c

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arch/x86/kvm/reverse_cpuid.h

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