From: Waiman Long <[email protected]> The l1tf_vmx_mitigation is only set to VMENTER_L1D_FLUSH_NOT_REQUIRED when the ARCH_CAPABILITIES MSR indicates that L1D flush is not required. However, if the CPU is not affected by L1TF, l1tf_vmx_mitigation will still be set to VMENTER_L1D_FLUSH_AUTO. This is certainly not the best option for a !X86_BUG_L1TF CPU.
So force l1tf_vmx_mitigation to VMENTER_L1D_FLUSH_NOT_REQUIRED to make it more explicit in case users are checking the vmentry_l1d_flush parameter. Signed-off-by: Waiman Long <[email protected]> [Patch rewritten accoring to Borislav Petkov's suggestion. - Paolo] Signed-off-by: Paolo Bonzini <[email protected]> --- arch/x86/kvm/vmx/vmx.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index d4575ffb3cec..e7970a2e8eae 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -209,6 +209,11 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf) struct page *page; unsigned int i; + if (!boot_cpu_has_bug(X86_BUG_L1TF)) { + l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED; + return 0; + } + if (!enable_ept) { l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_EPT_DISABLED; return 0; @@ -7995,12 +8000,10 @@ static int __init vmx_init(void) * contain 'auto' which will be turned into the default 'cond' * mitigation mode. */ - if (boot_cpu_has(X86_BUG_L1TF)) { - r = vmx_setup_l1d_flush(vmentry_l1d_flush_param); - if (r) { - vmx_exit(); - return r; - } + r = vmx_setup_l1d_flush(vmentry_l1d_flush_param); + if (r) { + vmx_exit(); + return r; } #ifdef CONFIG_KEXEC_CORE -- 1.8.3.1
