From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
Hyper-V Isolation VM doesn't have PIT/HPET legacy timer and only
provide stimer. Initialize Hyper-v stimer just after enabling
lapic to avoid kernel stuck during calibrating TSC due to no
available timer.
Signed-off-by: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
---
arch/x86/hyperv/hv_init.c | 29 -----------------------------
arch/x86/kernel/cpu/mshyperv.c | 22 ++++++++++++++++++++++
2 files changed, 22 insertions(+), 29 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 6f247e7e07eb..4a643a85d570 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -271,25 +271,6 @@ static struct syscore_ops hv_syscore_ops = {
.resume = hv_resume,
};
-static void (* __initdata old_setup_percpu_clockev)(void);
-
-static void __init hv_stimer_setup_percpu_clockev(void)
-{
- /*
- * Ignore any errors in setting up stimer clockevents
- * as we can run with the LAPIC timer as a fallback.
- */
- (void)hv_stimer_alloc(false);
-
- /*
- * Still register the LAPIC timer, because the direct-mode STIMER is
- * not supported by old versions of Hyper-V. This also allows users
- * to switch to LAPIC timer via /sys, if they want to.
- */
- if (old_setup_percpu_clockev)
- old_setup_percpu_clockev();
-}
-
static void __init hv_get_partition_id(void)
{
struct hv_get_partition_id *output_page;
@@ -396,16 +377,6 @@ void __init hyperv_init(void)
wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
}
- /*
- * hyperv_init() is called before LAPIC is initialized: see
- * apic_intr_mode_init() -> x86_platform.apic_post_init() and
- * apic_bsp_setup() -> setup_local_APIC(). The direct-mode STIMER
- * depends on LAPIC, so hv_stimer_alloc() should be called from
- * x86_init.timers.setup_percpu_clockev.
- */
- old_setup_percpu_clockev = x86_init.timers.setup_percpu_clockev;
- x86_init.timers.setup_percpu_clockev = hv_stimer_setup_percpu_clockev;
-
hv_apic_init();
x86_init.pci.arch_init = hv_pci_init;
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
index 6b5835a087a3..dcfbd2770d7f 100644
--- a/arch/x86/kernel/cpu/mshyperv.c
+++ b/arch/x86/kernel/cpu/mshyperv.c
@@ -214,6 +214,20 @@ static void __init hv_smp_prepare_boot_cpu(void)
#endif
}
+static void (* __initdata old_setup_initr_mode)(void);
+
+static void __init hv_setup_initr_mode(void)
+{
+ if (old_setup_initr_mode)
+ old_setup_initr_mode();
+
+ /*
+ * The direct-mode STIMER depends on LAPIC and so allocate
+ * STIMER after calling initr node callback.
+ */
+ (void)hv_stimer_alloc(false);
+}
+
static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
{
#ifdef CONFIG_X86_64
@@ -424,6 +438,7 @@ static void __init ms_hyperv_init_platform(void)
/* Register Hyper-V specific clocksource */
hv_init_clocksource();
#endif
+
/*
* TSC should be marked as unstable only after Hyper-V
* clocksource has been initialized. This ensures that the
@@ -431,6 +446,13 @@ static void __init ms_hyperv_init_platform(void)
*/
if (!(ms_hyperv.features & HV_ACCESS_TSC_INVARIANT))
mark_tsc_unstable("running on Hyper-V");
+
+ /*
+ * Override initr mode callback in order to allocate STIMER
+ * after initalizing LAPIC.
+ */
+ old_setup_initr_mode = x86_init.irqs.intr_mode_init;
+ x86_init.irqs.intr_mode_init = hv_setup_initr_mode;
}
static bool __init ms_hyperv_x2apic_available(void)
--
2.25.1
