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path: root/drivers/acpi/processor_idle.c
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Diffstat (limited to 'drivers/acpi/processor_idle.c')
-rw-r--r--drivers/acpi/processor_idle.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index ed56c6d20b08..2ae95df2e74f 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -642,6 +642,19 @@ static int acpi_idle_bm_check(void)
return bm_status;
}
+static void wait_for_freeze(void)
+{
+#ifdef CONFIG_X86
+ /* No delay is needed if we are in guest */
+ if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
+ return;
+#endif
+ /* Dummy wait op - must do something useless after P_LVL2 read
+ because chipsets cannot guarantee that STPCLK# signal
+ gets asserted in time to freeze execution properly. */
+ inl(acpi_gbl_FADT.xpm_timer_block.address);
+}
+
/**
* acpi_idle_do_entry - enter idle state using the appropriate method
* @cx: cstate data
@@ -658,10 +671,7 @@ static void __cpuidle acpi_idle_do_entry(struct acpi_processor_cx *cx)
} else {
/* IO port based C-state */
inb(cx->address);
- /* Dummy wait op - must do something useless after P_LVL2 read
- because chipsets cannot guarantee that STPCLK# signal
- gets asserted in time to freeze execution properly. */
- inl(acpi_gbl_FADT.xpm_timer_block.address);
+ wait_for_freeze();
}
}
@@ -682,8 +692,7 @@ static int acpi_idle_play_dead(struct cpuidle_device *dev, int index)
safe_halt();
else if (cx->entry_method == ACPI_CSTATE_SYSTEMIO) {
inb(cx->address);
- /* See comment in acpi_idle_do_entry() */
- inl(acpi_gbl_FADT.xpm_timer_block.address);
+ wait_for_freeze();
} else
return -ENODEV;
}