diff options
| author | Pawan Gupta <pawan.kumar.gupta@linux.intel.com> | 2024-03-11 08:57:09 -0700 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2024-04-08 19:27:06 +0200 |
| commit | 95a6ccbdc7199a14b71ad8901cb788ba7fb5167b (patch) | |
| tree | 2756d1354b90ff94be54ba551fbe6570365d2bf7 /Documentation/admin-guide/kernel-parameters.txt | |
| parent | ec9404e40e8f36421a2b66ecb76dc2209fe7f3ef (diff) | |
x86/bhi: Mitigate KVM by default
BHI mitigation mode spectre_bhi=auto does not deploy the software
mitigation by default. In a cloud environment, it is a likely scenario
where userspace is trusted but the guests are not trusted. Deploying
system wide mitigation in such cases is not desirable.
Update the auto mode to unconditionally mitigate against malicious
guests. Deploy the software sequence at VMexit in auto mode also, when
hardware mitigation is not available. Unlike the force =on mode,
software sequence is not deployed at syscalls in auto mode.
Suggested-by: Alexandre Chartre <alexandre.chartre@oracle.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>
Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 2dbe60c1db22..4fa46302f436 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6071,8 +6071,9 @@ on - unconditionally enable. off - unconditionally disable. - auto - (default) enable only if hardware mitigation - control(BHI_DIS_S) is available. + auto - (default) enable hardware mitigation + (BHI_DIS_S) if available, otherwise enable + alternate mitigation in KVM. spectre_v2= [X86,EARLY] Control mitigation of Spectre variant 2 (indirect branch speculation) vulnerability. |