1 files changed, 28 insertions, 4 deletions

diff --git a/tools/testing/selftests/x86/entry_from_vm86.c b/tools/testing/selftests/x86/entry_from_vm86.c
index 361466a2eaef..ade443a88421 100644
--- a/tools/testing/selftests/x86/entry_from_vm86.c
+++ b/tools/testing/selftests/x86/entry_from_vm86.c
@@ -95,6 +95,10 @@ asm (
         "int3\n\t"
         "vmcode_int80:\n\t"
         "int $0x80\n\t"
+        "vmcode_popf_hlt:\n\t"
+        "push %ax\n\t"
+        "popf\n\t"
+        "hlt\n\t"
         "vmcode_umip:\n\t"
         /* addressing via displacements */
         "smsw (2052)\n\t"
@@ -124,8 +128,8 @@ asm (
 
 extern unsigned char vmcode[], end_vmcode[];
 extern unsigned char vmcode_bound[], vmcode_sysenter[], vmcode_syscall[],
-        vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_umip[],
-        vmcode_umip_str[], vmcode_umip_sldt[];
+        vmcode_sti[], vmcode_int3[], vmcode_int80[], vmcode_popf_hlt[],
+        vmcode_umip[], vmcode_umip_str[], vmcode_umip_sldt[];
 
 /* Returns false if the test was skipped. */
 static bool do_test(struct vm86plus_struct *v86, unsigned long eip,
@@ -175,7 +179,7 @@ static bool do_test(struct vm86plus_struct *v86, unsigned long eip,
             (VM86_TYPE(ret) == rettype && VM86_ARG(ret) == retarg)) {
                 printf("[OK]\tReturned correctly\n");
         } else {
-                printf("[FAIL]\tIncorrect return reason\n");
+                printf("[FAIL]\tIncorrect return reason (started at eip = 0x%lx, ended at eip = 0x%lx)\n", eip, v86->regs.eip);
                 nerrs++;
         }
 
@@ -264,6 +268,9 @@ int main(void)
         v86.regs.ds = load_addr / 16;
         v86.regs.es = load_addr / 16;
 
+        /* Use the end of the page as our stack. */
+        v86.regs.esp = 4096;
+
         assert((v86.regs.cs & 3) == 0); /* Looks like RPL = 0 */
 
         /* #BR -- should deliver SIG??? */
@@ -295,6 +302,23 @@ int main(void)
         v86.regs.eflags &= ~X86_EFLAGS_IF;
         do_test(&v86, vmcode_sti - vmcode, VM86_STI, 0, "STI with VIP set");
 
+        /* POPF with VIP set but IF clear: should not trap */
+        v86.regs.eflags = X86_EFLAGS_VIP;
+        v86.regs.eax = 0;
+        do_test(&v86, vmcode_popf_hlt - vmcode, VM86_UNKNOWN, 0, "POPF with VIP set and IF clear");
+
+        /* POPF with VIP set and IF set: should trap */
+        v86.regs.eflags = X86_EFLAGS_VIP;
+        v86.regs.eax = X86_EFLAGS_IF;
+        do_test(&v86, vmcode_popf_hlt - vmcode, VM86_STI, 0, "POPF with VIP and IF set");
+
+        /* POPF with VIP clear and IF set: should not trap */
+        v86.regs.eflags = 0;
+        v86.regs.eax = X86_EFLAGS_IF;
+        do_test(&v86, vmcode_popf_hlt - vmcode, VM86_UNKNOWN, 0, "POPF with VIP clear and IF set");
+
+        v86.regs.eflags = 0;
+
         /* INT3 -- should cause #BP */
         do_test(&v86, vmcode_int3 - vmcode, VM86_TRAP, 3, "INT3");
 
@@ -318,7 +342,7 @@ int main(void)
         clearhandler(SIGSEGV);
 
         /* Make sure nothing explodes if we fork. */
-        if (fork() > 0)
+        if (fork() == 0)
                 return 0;
 
         return (nerrs == 0 ? 0 : 1);