main.c

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#include <xtf.h>
 
const char test_title[] = "LBR/TSX VMentry failure test";
 
static void int3_stub(void)
{
    /* Force a LBR record to be generated. */
    asm volatile ("jmp 1f; 1:");
 
    /*
     * After latching an LBR record, we need to force a subsequent vmentry.
     * Using printk() is the easiest way.
     */
    printk("Latched a Last Branch Record in the upper canonical half\n");
}
 
void test_main(void)
{
    uint64_t dbgctl;
 
    /* Alias everything in the upper canonical half. */
    pae_l4_identmap[256] = pae_l4_identmap[0];
    barrier();
 
    /* Probe for, and enable Last Branch Record. */
    if ( rdmsr_safe(MSR_DEBUGCTL, &dbgctl) )
        return xtf_skip("Skip: MSR_DEBUGCTL not available\n");
    else if ( wrmsr_safe(MSR_DEBUGCTL, dbgctl | DEBUGCTL_LBR) )
        return xtf_skip("Skip: MSR_DEBUGCTL.LBR not available\n");
 
    /* Construct a function pointer to int3_stub() via its upper alias. */
    void (*int3_stub_alias)(void) = _p(_u(int3_stub) | 0xffff800000000000);
 
    int3_stub_alias();
 
    /*
     * If XTF is alive at this point, the vmentry succeeded.  This will either
     * be unaffected hardware, or Xen has all applicable workarounds.
     */
    xtf_success("Success: No LBR/TSX VMentry failure in this configuration\n");
}
 
/*
 * Local variables:
 * mode: C
 * c-file-style: "BSD"
 * c-basic-offset: 4
 * tab-width: 4
 * indent-tabs-mode: nil
 * End:
 */