[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v1 5/5] xen/PMU: Cache MSR accesses during interrupt handling
On Tue, Sep 10, 2013 at 11:31:50AM -0400, Boris Ostrovsky wrote: > Avoid trapping to hypervisor on each MSR access during interrupt handling. > Instead, use cached MSR values provided in shared xenpmu_data by Xen. When > handling is completed, flush the registers to hypervisor who will load them > into HW. Looks OK. > > Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> > --- > arch/x86/xen/pmu.c | 15 ++++++++++++++- > include/xen/interface/xenpmu.h | 1 + > 2 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c > index d8b059b..bdd7c4a 100644 > --- a/arch/x86/xen/pmu.c > +++ b/arch/x86/xen/pmu.c > @@ -345,14 +345,27 @@ static void xen_convert_regs(struct cpu_user_regs > *xen_regs, > > irqreturn_t xen_pmu_irq_handler(int irq, void *dev_id) > { > - int ret = IRQ_NONE; > + int err, ret = IRQ_NONE; > struct pt_regs regs; > struct xenpmu_data *xenpmu_data = per_cpu(xenpmu_shared, > smp_processor_id()); > > + /* > + * While handling the interrupt MSR accesses will be cached > + * in PMU context > + */ > + xenpmu_data->pmu_flags |= PMU_CACHED; > xen_convert_regs(&xenpmu_data->regs, ®s); > if (x86_pmu.handle_irq(®s)) > ret = IRQ_HANDLED; > + xenpmu_data->pmu_flags &= ~PMU_CACHED; > + > + /* Write out cached context to HW */ > + err = HYPERVISOR_xenpmu_op(XENPMU_flush, NULL); > + if (err) { > + WARN(1, "%s failed hypercall, err: %d\n", __func__, err); > + return IRQ_NONE; > + } > > return ret; > } > diff --git a/include/xen/interface/xenpmu.h b/include/xen/interface/xenpmu.h > index 16fe1ab..ec0e802 100644 > --- a/include/xen/interface/xenpmu.h > +++ b/include/xen/interface/xenpmu.h > @@ -16,6 +16,7 @@ > #define XENPMU_init 4 > #define XENPMU_finish 5 > #define XENPMU_lvtpc_set 6 > +#define XENPMU_flush 7 /* Write cached MSR values to HW */ > > /* Parameter structure for HYPERVISOR_xenpmu_op call */ > struct xenpmu_params { > -- > 1.8.1.4 > _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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