[PATCH 0/2] Fix wild/dangling pointer in x86 ptp_kvm

[Zelin Deng <zelin.deng@linux.alibaba.com>]

When I was doing PTP_SYS_OFFSET_PRECISE ioctl in VM which has 128 vCPUs,
I got error returned occasionally. Then I checked the routine of
"getcrosststamp". I found in kvm_arch_ptp_get_crosststamp() of x86,
pvclock vcpu time info was got from hv_clock arrary which has only 64
elements. Hence this ioctl is executed on vCPU > 64, a wild/dangling
pointer will be got, which had casued the error.
To confirm this finding, I wrote a simple PTP_SYS_OFFSET_PRECISE ioctl
test and used "taskset -c n" to run the test, when it was executed on
vCPUs >= 64 it returned error.
This patchset exposes this_cpu_pvti() to get per cpu pvclock vcpu time
info of vCPUs >= 64 insdead of getting them from hv_clock arrary.

Zelin Deng (2):
  x86/kvmclock: Move this_cpu_pvti into kvmclock.h
  ptp: Fix ptp_kvm_getcrosststamp issue for x86 ptp_kvm

 arch/x86/include/asm/kvmclock.h | 14 ++++++++++++++
 arch/x86/kernel/kvmclock.c      | 13 ++-----------
 drivers/ptp/ptp_kvm_x86.c       |  9 ++-------
 3 files changed, 18 insertions(+), 18 deletions(-)

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1.8.3.1