KVM: selftests: Don't skip L2's VMCALL in SMM test for SVM guest

Don't skip the vmcall() in l2_guest_code() prior to re-entering L2, doing
so will result in L2 running to completion, popping '0' off the stack for
RET, jumping to address '0', and ultimately dying with a triple fault
shutdown.

It's not at all obvious why the test re-enters L2 and re-executes VMCALL,
but presumably it serves a purpose.  The VMX path doesn't skip vmcall(),
and the test can't possibly have passed on SVM, so just do what VMX does.

Fixes: d951b22 ("KVM: selftests: smm_test: Test SMM enter from L2")
Cc: Maxim Levitsky <[email protected]>
Signed-off-by: Sean Christopherson <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Vitaly Kuznetsov <[email protected]>
Tested-by: Vitaly Kuznetsov <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

Author: sean-jc

tools/testing/selftests/kvm/x86_64/smm_test.c

@@ -105,7 +105,6 @@ static void guest_code(void *arg)
 
 		if (cpu_has_svm()) {
 			run_guest(svm->vmcb, svm->vmcb_gpa);
-			svm->vmcb->save.rip += 3;
 			run_guest(svm->vmcb, svm->vmcb_gpa);
 		} else {
 			vmlaunch();