Xen Test Framework
main.c
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1 
35 #include <xtf.h>
36 
37 const char test_title[] = "LBR/TSX VMentry failure test";
38 
39 static void int3_stub(void)
40 {
41  /* Force a LBR record to be generated. */
42  asm volatile ("jmp 1f; 1:");
43 
44  /*
45  * After latching an LBR record, we need to force a subsequent vmentry.
46  * Using printk() is the easiest way.
47  */
48  printk("Latched a Last Branch Record in the upper canonical half\n");
49 }
50 
51 void test_main(void)
52 {
53  uint64_t dbgctl;
54 
55  /* Alias everything in the upper canonical half. */
56  pae_l4_identmap[256] = pae_l4_identmap[0];
57  barrier();
58 
59  /* Probe for, and enable Last Branch Record. */
60  if ( rdmsr_safe(MSR_DEBUGCTL, &dbgctl) )
61  return xtf_skip("Skip: MSR_DEBUGCTL not available\n");
62  else if ( wrmsr_safe(MSR_DEBUGCTL, dbgctl | DEBUGCTL_LBR) )
63  return xtf_skip("Skip: MSR_DEBUGCTL.LBR not available\n");
64 
65  /* Construct a function pointer to int3_stub() via its upper alias. */
66  void (*int3_stub_alias)(void) = _p(_u(int3_stub) | 0xffff800000000000);
67 
68  int3_stub_alias();
69 
70  /*
71  * If XTF is alive at this point, the vmentry succeeded. This will either
72  * be unaffected hardware, or Xen has all applicable workarounds.
73  */
74  xtf_success("Success: No LBR/TSX VMentry failure in this configuration\n");
75 }
76 
77 /*
78  * Local variables:
79  * mode: C
80  * c-file-style: "BSD"
81  * c-basic-offset: 4
82  * tab-width: 4
83  * indent-tabs-mode: nil
84  * End:
85  */
barrier
#define barrier()
Definition: compiler.h:30
MSR_DEBUGCTL
#define MSR_DEBUGCTL
Definition: msr-index.h:30
_u
#define _u(v)
Express an arbitrary value v as unsigned long.
Definition: numbers.h:53
printk
void printk(const char *fmt,...)
Definition: console.c:134
xtf_success
void xtf_success(const char *fmt,...)
Report test success.
Definition: report.c:38
test_main
void test_main(void)
To be implemented by each test, as its entry point.
Definition: main.c:137
uint64_t
__UINT64_TYPE__ uint64_t
Definition: stdint.h:17
int3_stub
static void int3_stub(void)
Definition: main.c:39
xtf_skip
void xtf_skip(const char *fmt,...)
Report a test skip.
Definition: report.c:66
test_title
const char test_title[]
The title of the test.
Definition: main.c:14
_p
#define _p(v)
Express an abitrary integer v as void *.
Definition: numbers.h:48
rdmsr_safe
static bool rdmsr_safe(uint32_t idx, uint64_t *val)
Wrapper around rdmsr which safely catches #GP[0].
Definition: msr.h:35
wrmsr_safe
static bool wrmsr_safe(uint32_t idx, uint64_t val)
Wrapper around wrmsr which safely catches #GP[0].
Definition: msr.h:69
DEBUGCTL_LBR
#define DEBUGCTL_LBR
Definition: msr-index.h:31
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