[PATCH] KVM: nVMX: Check that HLT activity state is supported

[Nikita Leshenko <nikita.leshchenko@oracle.com>]

Fail VM entry if GUEST_ACTIVITY_HLT is unsupported. According to "SDM A.6 -
Miscellaneous Data", VM entry should fail if the HLT activity is not marked as
supported on IA32_VMX_MISC MSR.

Usermode might disable GUEST_ACTIVITY_HLT support in the vCPU with
vmx_restore_vmx_misc(). Before this commit VM entries would have succeeded
anyway.

Reviewed-by: Liran Alon <liran.alon@oracle.com>
Reviewed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Nikita Leshenko <nikita.leshchenko@oracle.com>
---
 arch/x86/kvm/vmx/nested.c | 16 ++++++++++++----
 arch/x86/kvm/vmx/nested.h |  5 +++++
 2 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 46af3a5e9209..3165e2f7992f 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2656,11 +2656,19 @@ static int nested_vmx_check_vmcs_link_ptr(struct kvm_vcpu *vcpu,
 /*
  * Checks related to Guest Non-register State
  */
-static int nested_check_guest_non_reg_state(struct vmcs12 *vmcs12)
+static int nested_check_guest_non_reg_state(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
 {
-	if (vmcs12->guest_activity_state != GUEST_ACTIVITY_ACTIVE &&
-	    vmcs12->guest_activity_state != GUEST_ACTIVITY_HLT)
+	switch (vmcs12->guest_activity_state) {
+	case GUEST_ACTIVITY_ACTIVE:
+		/* Always supported */
+		break;
+	case GUEST_ACTIVITY_HLT:
+		if (!nested_cpu_has_activity_state_hlt(vcpu))
+			return -EINVAL;
+		break;
+	default:
 		return -EINVAL;
+	}
 
 	return 0;
 }
@@ -2710,7 +2718,7 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
 	     (vmcs12->guest_bndcfgs & MSR_IA32_BNDCFGS_RSVD)))
 		return -EINVAL;
 
-	if (nested_check_guest_non_reg_state(vmcs12))
+	if (nested_check_guest_non_reg_state(vcpu, vmcs12))
 		return -EINVAL;
 
 	return 0;
diff --git a/arch/x86/kvm/vmx/nested.h b/arch/x86/kvm/vmx/nested.h
index e847ff1019a2..4a294d3ff820 100644
--- a/arch/x86/kvm/vmx/nested.h
+++ b/arch/x86/kvm/vmx/nested.h
@@ -123,6 +123,11 @@ static inline bool nested_cpu_has_zero_length_injection(struct kvm_vcpu *vcpu)
 	return to_vmx(vcpu)->nested.msrs.misc_low & VMX_MISC_ZERO_LEN_INS;
 }
 
+static inline bool nested_cpu_has_activity_state_hlt(struct kvm_vcpu *vcpu)
+{
+	return to_vmx(vcpu)->nested.msrs.misc_low & VMX_MISC_ACTIVITY_HLT;
+}
+
 static inline bool nested_cpu_supports_monitor_trap_flag(struct kvm_vcpu *vcpu)
 {
 	return to_vmx(vcpu)->nested.msrs.procbased_ctls_high &
-- 
2.20.1