nVMX x86: Check VMX-preemption timer controls on vmentry of L2 guests

[ Upstream commit 14aa61d0a9eb3ddad06c3a0033f88b5fa7f05613 ]

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@oracle.com>
Reviewed-by: Mihai Carabas <mihai.carabas@oracle.com>
Reviewed-by: Liran Alon <liran.alon@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Stable-dep-of: a44b331614e6 ("KVM: x86/vmx: Do not skip segment attributes if unusable bit is set")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 9bb696d7300c079578680d08f0dbafa786b802e6..f8ad29968e85348e0b5d4d62895f139df71cce8d 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2062,6 +2062,12 @@ 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))
@@ -12609,6 +12615,10 @@ 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;