From fe1140cc369410a9c206fdb7aaabc644bd213dc2 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Sat, 23 Feb 2013 17:05:29 +0100 Subject: [PATCH] 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 Signed-off-by: Jan Kiszka Signed-off-by: Gleb Natapov --- arch/x86/kernel/kvmclock.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c index 5bedbdddf1f2..b730efad6fe9 100644 --- a/arch/x86/kernel/kvmclock.c +++ b/arch/x86/kernel/kvmclock.c @@ -160,8 +160,12 @@ int kvm_register_clock(char *txt) { 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 @@ int __init kvm_setup_vsyscall_timeinfo(void) 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(); -- 2.45.2