On Wed, 27 Jan 2021 at 01:26, Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote: > > On 26/01/21 02:28, Wanpeng Li wrote: > > ping, > > On Mon, 18 Jan 2021 at 17:08, Wanpeng Li <kernellwp@xxxxxxxxx> wrote: > >> > >> From: Wanpeng Li <wanpengli@xxxxxxxxxxx> > >> > >> The per-cpu vsyscall pvclock data pointer assigns either an element of the > >> static array hv_clock_boot (#vCPU <= 64) or dynamically allocated memory > >> hvclock_mem (vCPU > 64), the dynamically memory will not be allocated if > >> kvmclock vsyscall is disabled, this can result in cpu hotpluged fails in > >> kvmclock_setup_percpu() which returns -ENOMEM. This patch fixes it by not > >> assigning vsyscall pvclock data pointer if kvmclock vdso_clock_mode is not > >> VDSO_CLOCKMODE_PVCLOCK. > > I am sorry, I still cannot figure out this patch. > > Is hotplug still broken if kvm vsyscall is enabled? Just when kvm vsyscall is disabled. :) # lscpu Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 88 On-line CPU(s) list: 0-63 Off-line CPU(s) list: 64-87 # cat /proc/cmdline BOOT_IMAGE=/vmlinuz-5.10.0-rc3-tlinux2-0050+ root=/dev/mapper/cl-root ro rd.lvm.lv=cl/root rhgb quiet console=ttyS0 LANG=en_US .UTF-8 no-kvmclock-vsyscall # echo 1 > /sys/devices/system/cpu/cpu76/online -bash: echo: write error: Cannot allocate memory Wanpeng