ptp: Fix ptp_kvm_getcrosststamp issue for x86 ptp_kvm

hv_clock is preallocated to have only HVC_BOOT_ARRAY_SIZE (64) elements;
if the PTP_SYS_OFFSET_PRECISE ioctl is executed on vCPUs whose index is
64 of higher, retrieving the struct pvclock_vcpu_time_info pointer with
"src = &hv_clock[cpu].pvti" will result in an out-of-bounds access and
a wild pointer.  Change it to "this_cpu_pvti()" which is guaranteed to
be valid.

Fixes: 95a3d4454bb1 ("Switch kvmclock data to a PER_CPU variable")
Signed-off-by: Zelin Deng <>
Cc: <>
Message-Id: <>
Signed-off-by: Paolo Bonzini <>
1 file changed