Re: [Qemu-devel] [PATCH v2 2/3] hw/arm/virt: Add PMU node for virt machine

[Shannon Zhao <zhaoshenglong@huawei.com>]

On 2016/4/25 1:28, Andrew Jones wrote:
> On Sat, Apr 23, 2016 at 06:04:14PM +0800, Shannon Zhao wrote:
>> > From: Shannon Zhao <shannon.zhao@linaro.org>
>> > 
>> > Add a virtual PMU device for virt machine while use PPI 7 for PMU
>> > overflow interrupt number.
>> > 
>> > Signed-off-by: Shannon Zhao <shannon.zhao@linaro.org>
>> > ---
>> >  hw/arm/virt.c         | 31 +++++++++++++++++++++++++++++++
>> >  include/hw/arm/virt.h |  4 ++++
>> >  include/sysemu/kvm.h  |  1 +
>> >  stubs/kvm.c           |  5 +++++
>> >  target-arm/kvm64.c    | 39 +++++++++++++++++++++++++++++++++++++++
>> >  5 files changed, 80 insertions(+)
>> > 
>> > diff --git a/hw/arm/virt.c b/hw/arm/virt.c
>> > index 56d35c7..d77b314 100644
>> > --- a/hw/arm/virt.c
>> > +++ b/hw/arm/virt.c
>> > @@ -428,6 +428,35 @@ static void fdt_add_gic_node(VirtBoardInfo *vbi, int type)
>> >      qemu_fdt_setprop_cell(vbi->fdt, "/intc", "phandle", vbi->gic_phandle);
>> >  }
>> >  
>> > +static void fdt_add_pmu_nodes(const VirtBoardInfo *vbi)
>> > +{
>> > +    CPUState *cpu;
>> > +    ARMCPU *armcpu;
>> > +    uint32_t irqflags = GIC_FDT_IRQ_FLAGS_LEVEL_HI;
>> > +
>> > +    CPU_FOREACH(cpu) {
>> > +        armcpu = ARM_CPU(cpu);
>> > +        if (!armcpu->has_pmu) {
>> > +            return;
>> > +        }
>> > +
>> > +        kvm_arm_pmu_create(cpu, PPI(VIRTUAL_PMU_IRQ));
>> > +    }
>> > +
>> > +    irqflags = deposit32(irqflags, GIC_FDT_IRQ_PPI_CPU_START,
>> > +                         GIC_FDT_IRQ_PPI_CPU_WIDTH, (1 << vbi->smp_cpus) - 1);
> The shift will overflow when configuring a machine to have more than
> 32 cpus. You should confirm smp_cpus is <= GIC_FDT_IRQ_PPI_CPU_WIDTH
> before generating a mask this way, otherwise you can just pass in 0xff.
> 
Ah, right. So it could check the gictype like what we do in
fdt_add_timer_nodes.

Thanks,
-- 
Shannon