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Andrew Cooper
a7d8ce7844
XEN_DOMCTL_gdbsx_domstatus is already safe. It loops at most over every vcpu in a domain and breaks at the first vcpu with an event pending, marking it as not-pending. XEN_DOMCTL_gdbsx_pausevcpu had an incorrect bounds check against the vcpu id, allowing an overflow of d->vcpu[] with an id between d->max_vcpus and MAX_VIRT_CPUS. It was also able to overflow a vcpus pause count by many repeated hypercalls. The bounds check is fixed, and vcpu_pause() has been replaced with vcpu_pause_by_systemcontroller() which cuts out at 255 uses. XEN_DOMCTL_gdbsx_unpausevcpu suffered from the same bounds problems as its pause counterpart, and is fixed in exactly the same way. Despite the atomic_read(&v->pause_count), this code didn't successfully prevent against an underflow of the vcpu pause count. The vcpu_unpause() has been replaced with vcpu_pause_by_systemcontroller() which correctly prevents against underflow. The printk() is updated to have a proper guest logging level, and provide more useful information in the XSM case of one domain having debugger privileges over another. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Reviewed-by: Tim Deegan <tim@xen.org> Reviewed-by: Jan Beulich <jbeulich@suse.com>