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Diffstat (limited to 'Documentation/admin-guide/kernel-parameters.txt')
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5cde1ff32ff3..5a67e409d370 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1967,10 +1967,84 @@ (virtualized real and unpaged mode) on capable Intel chips. Default is 1 (enabled) + kvm-intel.vmentry_l1d_flush=[KVM,Intel] Mitigation for L1 Terminal Fault + CVE-2018-3620. + + Valid arguments: never, cond, always + + always: L1D cache flush on every VMENTER. + cond: Flush L1D on VMENTER only when the code between + VMEXIT and VMENTER can leak host memory. + never: Disables the mitigation + + Default is cond (do L1 cache flush in specific instances) + kvm-intel.vpid= [KVM,Intel] Disable Virtual Processor Identification feature (tagged TLBs) on capable Intel chips. Default is 1 (enabled) + l1tf= [X86] Control mitigation of the L1TF vulnerability on + affected CPUs + + The kernel PTE inversion protection is unconditionally + enabled and cannot be disabled. + + full + Provides all available mitigations for the + L1TF vulnerability. Disables SMT and + enables all mitigations in the + hypervisors, i.e. unconditional L1D flush. + + SMT control and L1D flush control via the + sysfs interface is still possible after + boot. Hypervisors will issue a warning + when the first VM is started in a + potentially insecure configuration, + i.e. SMT enabled or L1D flush disabled. + + full,force + Same as 'full', but disables SMT and L1D + flush runtime control. Implies the + 'nosmt=force' command line option. + (i.e. sysfs control of SMT is disabled.) + + flush + Leaves SMT enabled and enables the default + hypervisor mitigation, i.e. conditional + L1D flush. + + SMT control and L1D flush control via the + sysfs interface is still possible after + boot. Hypervisors will issue a warning + when the first VM is started in a + potentially insecure configuration, + i.e. SMT enabled or L1D flush disabled. + + flush,nosmt + + Disables SMT and enables the default + hypervisor mitigation. + + SMT control and L1D flush control via the + sysfs interface is still possible after + boot. Hypervisors will issue a warning + when the first VM is started in a + potentially insecure configuration, + i.e. SMT enabled or L1D flush disabled. + + flush,nowarn + Same as 'flush', but hypervisors will not + warn when a VM is started in a potentially + insecure configuration. + + off + Disables hypervisor mitigations and doesn't + emit any warnings. + + Default is 'flush'. + + For details see: Documentation/admin-guide/l1tf.rst + l2cr= [PPC] l3cr= [PPC] @@ -2687,6 +2761,10 @@ nosmt [KNL,S390] Disable symmetric multithreading (SMT). Equivalent to smt=1. + [KNL,x86] Disable symmetric multithreading (SMT). + nosmt=force: Force disable SMT, cannot be undone + via the sysfs control file. + nospectre_v2 [X86] Disable all mitigations for the Spectre variant 2 (indirect branch prediction) vulnerability. System may allow data leaks with this option, which is equivalent |