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KVM: VMX: Set VMENTER_L1D_FLUSH_NOT_REQUIRED if !X86_BUG_L1TF 

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 <longman@redhat.com>
[Patch rewritten accoring to Borislav Petkov's suggestion. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Waiman Long 2019-08-26 15:30:23 -04:00 committed by Paolo Bonzini
parent 0944442045
commit 19a36d329f
1 changed files with 9 additions and 6 deletions
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15
arch/x86/kvm/vmx/vmx.c
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@ -209,6 +209,11 @@ static int vmx_setup_l1d_flush(enum vmx_l1d_flush_state l1tf)
struct page *page; struct page *page;
unsigned int i; unsigned int i;
if (!boot_cpu_has_bug(X86_BUG_L1TF)) {
l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_NOT_REQUIRED;
return 0;
}
if (!enable_ept) { if (!enable_ept) {
l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_EPT_DISABLED; l1tf_vmx_mitigation = VMENTER_L1D_FLUSH_EPT_DISABLED;
return 0; return 0;
@ -7995,12 +8000,10 @@ static int __init vmx_init(void)
* contain 'auto' which will be turned into the default 'cond' * contain 'auto' which will be turned into the default 'cond'
* mitigation mode. * mitigation mode.
*/ */
if (boot_cpu_has(X86_BUG_L1TF)) { r = vmx_setup_l1d_flush(vmentry_l1d_flush_param);
r = vmx_setup_l1d_flush(vmentry_l1d_flush_param); if (r) {
if (r) { vmx_exit();
vmx_exit(); return r;
return r;
}
} }
#ifdef CONFIG_KEXEC_CORE #ifdef CONFIG_KEXEC_CORE