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Diffstat (limited to 'arch/x86/xen/time.c')
-rw-r--r--arch/x86/xen/time.c24
1 files changed, 23 insertions, 1 deletions
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index d9c945ee1100..9ef0a5cca96e 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -558,6 +558,11 @@ static void xen_hvm_setup_cpu_clockevents(void)
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
@@ -567,7 +572,22 @@ void __init xen_hvm_init_time_ops(void)
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;
}
@@ -577,6 +597,8 @@ void __init xen_hvm_init_time_ops(void)
x86_cpuinit.setup_percpu_clockev = xen_hvm_setup_cpu_clockevents;
x86_platform.set_wallclock = xen_set_wallclock;
+
+ hvm_time_initialized = true;
}
#endif