1342798cc1
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: David Ahern <dsahern@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Robert Richter <robert.richter@amd.com> Tested-by: Robert Richter <robert.richter@amd.com> Reviewed-by: Robert 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.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> |
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| .. | ||
| firewire | ||
| hv | ||
| include/tools | ||
| lguest | ||
| lib/traceevent | ||
| nfsd | ||
| perf | ||
| power | ||
| scripts | ||
| testing | ||
| usb | ||
| virtio | ||
| vm | ||
| Makefile | ||