On Wed, Sep 05, 2012 at 08:35:24AM +0200, Ingo Molnar wrote: > > * Yan, Zheng <[email protected]> wrote: > > > From: "Yan, Zheng" <[email protected]> > > > > Initializing uncore PMU on virtualized CPU may hang the kernel. > > This is because kvm does not emulate the entire hardware. Thers > > are lots of uncore related MSRs, making kvm enumerate them all > > is a non-trival task. So just disable uncore on virtualized CPU. > > > > Signed-off-by: Yan, Zheng <[email protected]> > > --- > > arch/x86/kernel/cpu/perf_event_intel_uncore.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/arch/x86/kernel/cpu/perf_event_intel_uncore.c > > b/arch/x86/kernel/cpu/perf_event_intel_uncore.c > > index 0a55710..2f005ba 100644 > > --- a/arch/x86/kernel/cpu/perf_event_intel_uncore.c > > +++ b/arch/x86/kernel/cpu/perf_event_intel_uncore.c > > @@ -2898,6 +2898,9 @@ static int __init intel_uncore_init(void) > > if (boot_cpu_data.x86_vendor != X86_VENDOR_INTEL) > > return -ENODEV; > > > > + if (cpu_has_hypervisor) > > + return -ENODEV; > > + > > ret = uncore_pci_init(); > > if (ret) > > goto fail; > > Cannot the presence of the uncore hardware be detected in a > cleaner fashion, via the PCI config space and such?
Probably just by reading the registers and see that they are 0 and when writing read back and check. And the code should not hang when that happens, then this check wouldn't be needed. -Andi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
