KVM: nVMX: Store vmcs.EXIT_QUALIFICATION as an unsigned long, not u32

Use an unsigned long for 'exit_qual' in nested_vmx_reflect_vmexit(), the
EXIT_QUALIFICATION field is naturally sized, not a 32-bit field.

The bug is most easily observed by doing VMXON (or any VMX instruction)
in L2 with a negative displacement, in which case dropping the upper
bits on nested VM-Exit results in L1 calculating the wrong virtual
address for the memory operand, e.g. "vmxon -0x8(%rbp)" yields:

  Unhandled cpu exception 14 #PF at ip 0000000000400553
  rbp=0000000000537000 cr2=0000000100536ff8

Fixes: fbdd502 ("KVM: nVMX: Move VM-Fail check out of nested_vmx_exit_reflected()")
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200423001127.13490-1-sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/nested.c

@@ -5814,7 +5814,8 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 exit_reason = vmx->exit_reason;
-	u32 exit_intr_info, exit_qual;
+	unsigned long exit_qual;
+	u32 exit_intr_info;
 
 	WARN_ON_ONCE(vmx->nested.nested_run_pending);