pvclock data pointers of vCPUs >= HVC_BOOT_ARRAY_SIZE (64) are stored in
hvclock_mem wihch is initialized in kvmclock_init_mem().
Here're 3 scenarios in current implementation:
- no-kvmclock is set in cmdline. kvm pv clock driver is disabled,
no impact.
- no-kvmclock-vsyscall is set in cmdline. kvmclock_init_mem() won't
be called. No memory for storing pvclock data of vCPUs >= 64, vCPUs
>= 64 can not be online or hotpluged.
- tsc unstable. kvmclock_init_mem() won't be called. vCPUs >= 64 can
not be online or hotpluged.
It's not reasonable that vCPUs hotplug have been impacted by last 2
scenarios. Hence move kvmclock_init_mem() to front, in case hvclock_mem
can not be initialized unexpectedly.
Fixes: 6a1cac56f41f9 (x86/kvm: Use __bss_decrypted attribute in shared variables)
Signed-off-by: Zelin Deng <zelin.deng@xxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/kvmclock.c | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 34b18f6eeb2c..1abbda25e037 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -271,7 +271,14 @@ static int __init kvm_setup_vsyscall_timeinfo(void)
{
#ifdef CONFIG_X86_64
u8 flags;
+#endif
+
+ if (!kvmclock)
+ return 0;
+
+ kvmclock_init_mem();
+#ifdef CONFIG_X86_64
if (!per_cpu(hv_clock_per_cpu, 0) || !kvmclock_vsyscall)
return 0;
@@ -282,8 +289,6 @@ static int __init kvm_setup_vsyscall_timeinfo(void)
kvm_clock.vdso_clock_mode = VDSO_CLOCKMODE_PVCLOCK;
#endif
- kvmclock_init_mem();
-
return 0;
}
early_initcall(kvm_setup_vsyscall_timeinfo);
--
2.20.1
