[PATCH 1/4] KVM: nVMX: Check GUEST_SYSENTER_ESP and GUEST_SYSENTER_EIP on vmentry of nested guests

[Krish Sadhukhan <krish.sadhukhan@oracle.com>]

According to section "Checks on Guest Control Registers, Debug Registers, and
and MSRs" in Intel SDM vol 3C, the following checks are performed on vmentry
of nested guests:

    "The IA32_SYSENTER_ESP field and the IA32_SYSENTER_EIP field must each
     contain a canonical address."

Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Reviewed-by: Karl Heubaum <karl.heubaum@oracle.com>
---
 arch/x86/kvm/vmx/nested.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 0e7c9301fe86..a2d1c305a7d8 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2770,6 +2770,10 @@ static int nested_vmx_check_guest_state(struct kvm_vcpu *vcpu,
 	    CC(!nested_guest_cr4_valid(vcpu, vmcs12->guest_cr4)))
 		return -EINVAL;
 
+	if (CC(!is_noncanonical_address(vmcs12->guest_sysenter_esp)) ||
+	    CC(!is_noncanonical_address(vmcs12->guest_sysenter_eip)))
+		return -EINVAL;
+
 	if ((vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) &&
 	    CC(!kvm_pat_valid(vmcs12->guest_ia32_pat)))
 		return -EINVAL;
-- 
2.20.1