1. 16 Oct, 2012 1 commit
    • David Ahern's avatar
      perf tool: Precise mode requires exclude_guest · 1342798c
      David Ahern authored
      Summary of events per Peter:
      
        "Intel PEBS in VT-x context uses the DS address as a guest linear address,
        even though its programmed by the host as a host linear address. This
        either results in guest memory corruption and or the hardware faulting and
        'crashing' the virtual machine.  Therefore we have to disable PEBS on VT-x
        enter and re-enable on VT-x exit, enforcing a strict exclude_guest.
      
        AMB IBS does work but doesn't currently support exclude_* at all,
        setting an exclude_* bit will make it fail."
      
      This patch handles userspace perf command, setting the exclude_guest
      attribute if precise mode is requested, but only if a user has not
      specified a request for guest or host only profiling (G or H attribute).
      
      Kernel side AMD currently ignores all exclude_* bits, so there is no impact
      to existing IBS code paths. Robert Richter has a patch where IBS code will
      return EINVAL if an exclude_* bit is set. When this goes in it means use
      of :p on AMD with IBS will first fail with EINVAL (because exclude_guest
      will be set). Then the existing fallback code within perf will unset
      exclude_guest and try again. The second attempt will succeed if the CPU
      supports IBS profiling.
      Signed-off-by: default avatarDavid Ahern <dsahern@gmail.com>
      Acked-by: default avatarPeter Zijlstra <peterz@infradead.org>
      Acked-by: default avatarRobert Richter <robert.richter@amd.com>
      Tested-by: default avatarRobert Richter <robert.richter@amd.com>
      Reviewed-by: default avatarRobert Richter <robert.richter@amd.com>
      Cc: Avi Kivity <avi@redhat.com>
      Cc: Gleb Natapov <gleb@redhat.com>
      Cc: Ingo Molnar <mingo@kernel.org>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Robert Richter <robert.richter@amd.com>
      Link: http://lkml.kernel.org/r/1347569955-54626-2-git-send-email-dsahern@gmail.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
      1342798c
  2. 05 Oct, 2012 4 commits
  3. 04 Oct, 2012 11 commits
  4. 03 Oct, 2012 3 commits
  5. 02 Oct, 2012 21 commits