From 08f87f769b595151be1afeff53e144f543faa614 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 06 Dec 2023 09:51:13 +0000
Subject: [PATCH] add dts config
---
kernel/arch/x86/xen/time.c | 85 ++++++++++++++++++++++++++++++++----------
1 files changed, 65 insertions(+), 20 deletions(-)
diff --git a/kernel/arch/x86/xen/time.c b/kernel/arch/x86/xen/time.c
index 01dcccf..8183d17 100644
--- a/kernel/arch/x86/xen/time.c
+++ b/kernel/arch/x86/xen/time.c
@@ -28,7 +28,7 @@
#include "xen-ops.h"
-/* Xen may fire a timer up to this many ns early */
+/* Minimum amount of time until next clock event fires */
#define TIMER_SLOP 100000
static u64 xen_sched_clock_offset __read_mostly;
@@ -39,6 +39,7 @@
struct pvclock_vcpu_time_info *info =
&HYPERVISOR_shared_info->vcpu_info[0].time;
+ setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ);
return pvclock_tsc_khz(info);
}
@@ -145,12 +146,19 @@
.notifier_call = xen_pvclock_gtod_notify,
};
+static int xen_cs_enable(struct clocksource *cs)
+{
+ vclocks_set_used(VDSO_CLOCKMODE_PVCLOCK);
+ return 0;
+}
+
static struct clocksource xen_clocksource __read_mostly = {
- .name = "xen",
- .rating = 400,
- .read = xen_clocksource_get_cycles,
- .mask = ~0,
- .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .name = "xen",
+ .rating = 400,
+ .read = xen_clocksource_get_cycles,
+ .mask = CLOCKSOURCE_MASK(64),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS,
+ .enable = xen_cs_enable,
};
/*
@@ -212,7 +220,7 @@
return 0;
}
-static const struct clock_event_device xen_timerop_clockevent = {
+static struct clock_event_device xen_timerop_clockevent __ro_after_init = {
.name = "xen",
.features = CLOCK_EVT_FEAT_ONESHOT,
@@ -273,7 +281,7 @@
return ret;
}
-static const struct clock_event_device xen_vcpuop_clockevent = {
+static struct clock_event_device xen_vcpuop_clockevent __ro_after_init = {
.name = "xen",
.features = CLOCK_EVT_FEAT_ONESHOT,
@@ -412,12 +420,13 @@
ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
/*
- * We don't disable VCLOCK_PVCLOCK entirely if it fails to register the
- * secondary time info with Xen or if we migrated to a host without the
- * necessary flags. On both of these cases what happens is either
- * process seeing a zeroed out pvti or seeing no PVCLOCK_TSC_STABLE_BIT
- * bit set. Userspace checks the latter and if 0, it discards the data
- * in pvti and fallbacks to a system call for a reliable timestamp.
+ * We don't disable VDSO_CLOCKMODE_PVCLOCK entirely if it fails to
+ * register the secondary time info with Xen or if we migrated to a
+ * host without the necessary flags. On both of these cases what
+ * happens is either process seeing a zeroed out pvti or seeing no
+ * PVCLOCK_TSC_STABLE_BIT bit set. Userspace checks the latter and
+ * if 0, it discards the data in pvti and fallbacks to a system
+ * call for a reliable timestamp.
*/
if (ret != 0)
pr_notice("Cannot restore secondary vcpu_time_info (err %d)",
@@ -443,7 +452,7 @@
ret = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_time_memory_area, 0, &t);
if (ret) {
- pr_notice("xen: VCLOCK_PVCLOCK not supported (err %d)\n", ret);
+ pr_notice("xen: VDSO_CLOCKMODE_PVCLOCK not supported (err %d)\n", ret);
free_page((unsigned long)ti);
return;
}
@@ -460,14 +469,14 @@
if (!ret)
free_page((unsigned long)ti);
- pr_notice("xen: VCLOCK_PVCLOCK not supported (tsc unstable)\n");
+ pr_notice("xen: VDSO_CLOCKMODE_PVCLOCK not supported (tsc unstable)\n");
return;
}
xen_clock = ti;
pvclock_set_pvti_cpu0_va(xen_clock);
- xen_clocksource.archdata.vclock_mode = VCLOCK_PVCLOCK;
+ xen_clocksource.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
}
static void __init xen_time_init(void)
@@ -519,7 +528,7 @@
void __init xen_init_time_ops(void)
{
xen_sched_clock_offset = xen_clocksource_read();
- pv_time_ops = xen_time_ops;
+ pv_ops.time = xen_time_ops;
x86_init.timers.timer_init = xen_time_init;
x86_init.timers.setup_percpu_clockev = x86_init_noop;
@@ -547,6 +556,11 @@
void __init xen_hvm_init_time_ops(void)
{
+ static bool hvm_time_initialized;
+
+ if (hvm_time_initialized)
+ return;
+
/*
* vector callback is needed otherwise we cannot receive interrupts
* on cpu > 0 and at this point we don't know how many cpus are
@@ -556,17 +570,48 @@
return;
if (!xen_feature(XENFEAT_hvm_safe_pvclock)) {
- pr_info("Xen doesn't support pvclock on HVM, disable pv timer");
+ pr_info_once("Xen doesn't support pvclock on HVM, disable pv timer");
+ return;
+ }
+
+ /*
+ * Only MAX_VIRT_CPUS 'vcpu_info' are embedded inside 'shared_info'.
+ * The __this_cpu_read(xen_vcpu) is still NULL when Xen HVM guest
+ * boots on vcpu >= MAX_VIRT_CPUS (e.g., kexec), To access
+ * __this_cpu_read(xen_vcpu) via xen_clocksource_read() will panic.
+ *
+ * The xen_hvm_init_time_ops() should be called again later after
+ * __this_cpu_read(xen_vcpu) is available.
+ */
+ if (!__this_cpu_read(xen_vcpu)) {
+ pr_info("Delay xen_init_time_common() as kernel is running on vcpu=%d\n",
+ xen_vcpu_nr(0));
return;
}
xen_sched_clock_offset = xen_clocksource_read();
- pv_time_ops = xen_time_ops;
+ pv_ops.time = xen_time_ops;
x86_init.timers.setup_percpu_clockev = xen_time_init;
x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
x86_platform.calibrate_tsc = xen_tsc_khz;
x86_platform.get_wallclock = xen_get_wallclock;
x86_platform.set_wallclock = xen_set_wallclock;
+
+ hvm_time_initialized = true;
}
#endif
+
+/* Kernel parameter to specify Xen timer slop */
+static int __init parse_xen_timer_slop(char *ptr)
+{
+ unsigned long slop = memparse(ptr, NULL);
+
+ xen_timerop_clockevent.min_delta_ns = slop;
+ xen_timerop_clockevent.min_delta_ticks = slop;
+ xen_vcpuop_clockevent.min_delta_ns = slop;
+ xen_vcpuop_clockevent.min_delta_ticks = slop;
+
+ return 0;
+}
+early_param("xen_timer_slop", parse_xen_timer_slop);
--
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