From: Peter Zijlstra <pet...@infradead.org> 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.
This patch enforces exclude_guest kernel side. Signed-off-by: David Ahern <dsah...@gmail.com> Cc: Ingo Molnar <mi...@kernel.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Robert Richter <robert.rich...@amd.com> Cc: Gleb Natapov <g...@redhat.com> Cc: Avi Kivity <a...@redhat.com> Link: https://lkml.org/lkml/2012/7/9/298 --- arch/x86/kernel/cpu/perf_event.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 915b876..4bc96c5 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -338,6 +338,9 @@ int x86_setup_perfctr(struct perf_event *event) /* BTS is currently only allowed for user-mode. */ if (!attr->exclude_kernel) return -EOPNOTSUPP; + + if (!attr->exclude_guest) + return -EOPNOTSUPP; } hwc->config |= config; @@ -380,6 +383,9 @@ int x86_pmu_hw_config(struct perf_event *event) if (event->attr.precise_ip) { int precise = 0; + if (!event->attr.exclude_guest) + return -EOPNOTSUPP; + /* Support for constant skid */ if (x86_pmu.pebs_active && !x86_pmu.pebs_broken) { precise++; -- 1.7.10.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
