Messages in this thread | | | Date | Wed, 12 Sep 2012 22:33:36 -0600 | From | David Ahern <> | Subject | Re: [PATCH 2/3] perf: require exclude_guest to use PEBS - kernel side enforcement |
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On 9/12/12 8:38 PM, Namhyung Kim wrote: > Hi David, > > On Wed, 12 Sep 2012 09:16:29 -0600, David Ahern wrote: >> From: Peter Zijlstra <peterz@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. >> > [snip] >> @@ -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; > > I see a whitespace problem here. :)
grr.... an extra freaking tab.
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