• David Hildenbrand's avatar
    KVM: s390: hardware support for guest debugging · 27291e21
    David Hildenbrand authored
    This patch adds support to debug the guest using the PER facility on s390.
    Single-stepping, hardware breakpoints and hardware watchpoints are supported. In
    order to use the PER facility of the guest without it noticing it, the control
    registers of the guest have to be patched and access to them has to be
    intercepted(stctl, stctg, lctl, lctlg).
    
    All PER program interrupts have to be intercepted and only the relevant PER
    interrupts for the guest have to be given back. Special care has to be taken
    about repeated exits on the same hardware breakpoint. The intervention of the
    host in the guests PER configuration is not fully transparent. PER instruction
    nullification can not be used by the guest and too many storage alteration
    events may be reported to the guest (if it is activated for special address
    ranges only) when the host concurrently debugging it.
    Signed-off-by: default avatarDavid Hildenbrand <dahi@linux.vnet.ibm.com>
    Signed-off-by: default avatarChristian Borntraeger <borntraeger@de.ibm.com>
    27291e21
guestdbg.c 11.8 KB