According to section "Checks on VMX Controls" in Intel SDM vol 3C, the
following check needs to be enforced on vmentry of L2 guests:
If the "activate VMX-preemption timer" VM-execution control is 0, the
the "save VMX-preemption timer value" VM-exit control must also be 0.
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
Reviewed-by: Mihai Carabas <mihai.carabas@xxxxxxxxxx>
Reviewed-by: Liran Alon <liran.alon@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index e665aa7..8c8f840 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2054,6 +2054,12 @@ static inline bool nested_cpu_has_shadow_vmcs(struct vmcs12 *vmcs12)
return nested_cpu_has2(vmcs12, SECONDARY_EXEC_SHADOW_VMCS);
}
+static inline bool nested_cpu_has_save_preemption_timer(struct vmcs12 *vmcs12)
+{
+ return vmcs12->vm_exit_controls &
+ VM_EXIT_SAVE_VMX_PREEMPTION_TIMER;
+}
+
static inline bool is_nmi(u32 intr_info)
{
return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
@@ -12409,6 +12415,10 @@ static int check_vmentry_prereqs(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
if (nested_vmx_check_msr_switch_controls(vcpu, vmcs12))
return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+ if (!nested_cpu_has_preemption_timer(vmcs12) &&
+ nested_cpu_has_save_preemption_timer(vmcs12))
+ return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
+
if (nested_vmx_check_pml_controls(vcpu, vmcs12))
return VMXERR_ENTRY_INVALID_CONTROL_FIELD;
--
2.9.5
