x86/xen: Get rid of paravirt op adjust_exception_frame
When running as Xen pv-guest the exception frame on the stack contains
%r11 and %rcx additional to the other data pushed by the processor.
Instead of having a paravirt op being called for each exception type
prepend the Xen specific code to each exception entry. When running as
Xen pv-guest just use the exception entry with prepended instructions,
otherwise use the entry without the Xen specific code.
[ tglx: Merged through tip to avoid ugly merge conflict ]
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: xen-devel@lists.xenproject.org
Cc: boris.ostrovsky@oracle.com
Cc: luto@amacapital.net
Link: http://lkml.kernel.org/r/20170831174249.26853-1-jg@pfupf.net
diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 03fb07d..3859fc1 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -579,6 +579,70 @@ static void xen_write_ldt_entry(struct desc_struct *dt, int entrynum,
preempt_enable();
}
+#ifdef CONFIG_X86_64
+struct trap_array_entry {
+ void (*orig)(void);
+ void (*xen)(void);
+ bool ist_okay;
+};
+
+static struct trap_array_entry trap_array[] = {
+ { debug, xen_xendebug, true },
+ { int3, xen_xenint3, true },
+ { double_fault, xen_double_fault, true },
+#ifdef CONFIG_X86_MCE
+ { machine_check, xen_machine_check, true },
+#endif
+ { nmi, xen_nmi, true },
+ { overflow, xen_overflow, false },
+#ifdef CONFIG_IA32_EMULATION
+ { entry_INT80_compat, xen_entry_INT80_compat, false },
+#endif
+ { page_fault, xen_page_fault, false },
+ { divide_error, xen_divide_error, false },
+ { bounds, xen_bounds, false },
+ { invalid_op, xen_invalid_op, false },
+ { device_not_available, xen_device_not_available, false },
+ { coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
+ { invalid_TSS, xen_invalid_TSS, false },
+ { segment_not_present, xen_segment_not_present, false },
+ { stack_segment, xen_stack_segment, false },
+ { general_protection, xen_general_protection, false },
+ { spurious_interrupt_bug, xen_spurious_interrupt_bug, false },
+ { coprocessor_error, xen_coprocessor_error, false },
+ { alignment_check, xen_alignment_check, false },
+ { simd_coprocessor_error, xen_simd_coprocessor_error, false },
+};
+
+static bool get_trap_addr(void **addr, unsigned int ist)
+{
+ unsigned int nr;
+ bool ist_okay = false;
+
+ /*
+ * Replace trap handler addresses by Xen specific ones.
+ * Check for known traps using IST and whitelist them.
+ * The debugger ones are the only ones we care about.
+ * Xen will handle faults like double_fault, * so we should never see
+ * them. Warn if there's an unexpected IST-using fault handler.
+ */
+ for (nr = 0; nr < ARRAY_SIZE(trap_array); nr++) {
+ struct trap_array_entry *entry = trap_array + nr;
+
+ if (*addr == entry->orig) {
+ *addr = entry->xen;
+ ist_okay = entry->ist_okay;
+ break;
+ }
+ }
+
+ if (WARN_ON(ist != 0 && !ist_okay))
+ return false;
+
+ return true;
+}
+#endif
+
static int cvt_gate_to_trap(int vector, const gate_desc *val,
struct trap_info *info)
{
@@ -591,40 +655,8 @@ static int cvt_gate_to_trap(int vector, const gate_desc *val,
addr = gate_offset(val);
#ifdef CONFIG_X86_64
- /*
- * Look for known traps using IST, and substitute them
- * appropriately. The debugger ones are the only ones we care
- * about. Xen will handle faults like double_fault,
- * so we should never see them. Warn if
- * there's an unexpected IST-using fault handler.
- */
- if (addr == (unsigned long)debug)
- addr = (unsigned long)xen_debug;
- else if (addr == (unsigned long)int3)
- addr = (unsigned long)xen_int3;
- else if (addr == (unsigned long)stack_segment)
- addr = (unsigned long)xen_stack_segment;
- else if (addr == (unsigned long)double_fault) {
- /* Don't need to handle these */
+ if (!get_trap_addr((void **)&addr, val->bits.ist))
return 0;
-#ifdef CONFIG_X86_MCE
- } else if (addr == (unsigned long)machine_check) {
- /*
- * when xen hypervisor inject vMCE to guest,
- * use native mce handler to handle it
- */
- ;
-#endif
- } else if (addr == (unsigned long)nmi)
- /*
- * Use the native version as well.
- */
- ;
- else {
- /* Some other trap using IST? */
- if (WARN_ON(val->bits.ist != 0))
- return 0;
- }
#endif /* CONFIG_X86_64 */
info->address = addr;