x86: kvmclock: Do not setup kvmclock vsyscall in the absence of that clock
This fixes boot lockups with "no-kvmclock", when the host is not
exposing this particular feature (QEMU: -cpu ...,-kvmclock) or when
the kvmclock initialization failed for whatever reason.
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 5bedbdd..b730efa 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -160,8 +160,12 @@
{
int cpu = smp_processor_id();
int low, high, ret;
- struct pvclock_vcpu_time_info *src = &hv_clock[cpu].pvti;
+ struct pvclock_vcpu_time_info *src;
+ if (!hv_clock)
+ return 0;
+
+ src = &hv_clock[cpu].pvti;
low = (int)__pa(src) | 1;
high = ((u64)__pa(src) >> 32);
ret = native_write_msr_safe(msr_kvm_system_time, low, high);
@@ -276,6 +280,9 @@
struct pvclock_vcpu_time_info *vcpu_time;
unsigned int size;
+ if (!hv_clock)
+ return 0;
+
size = PAGE_ALIGN(sizeof(struct pvclock_vsyscall_time_info)*NR_CPUS);
preempt_disable();