Re: [Qemu-devel] [PATCH v4] s390x/pci: add common function measurement block

[Pierre Morel <pmorel@linux.ibm.com>]

On 19/12/2018 10:48, Cornelia Huck wrote:
> On Tue, 18 Dec 2018 18:28:59 +0100
> Pierre Morel <pmorel@linux.ibm.com> wrote:
> 
>> From: Yi Min Zhao <zyimin@linux.ibm.com>
>>
>> Common function measurement block is used to report zPCI internal
>> counters of successful pcilg/stg/stb and rpcit instructions to
>> a memory location provided by the program.
>>
>> This patch introduces a new ZpciFmb structure and schedules a timer
>> callback to copy the zPCI measures to the FMB in the guest memory
>> at an interval time set to 4s.
>>
>> An error while attemping to update the FMB, would generate an error
>> event to the guest.
>>
>> The pcilg/stg/stb and rpcit interception handlers increase the
>> related counter on a successul call.
> 
> s/successul/successful/
> 
>> The guest shall pass a null FMBA (FMB address) in the FIB (Function
>> Information Block) when it issues a Modify PCI Function Control
>> instruction to switch off FMB and stop the corresponding timer.
>>
>> Signed-off-by: Yi Min Zhao <zyimin@linux.ibm.com>
>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>> ---
>>   hw/s390x/s390-pci-bus.c  |   4 +-
>>   hw/s390x/s390-pci-bus.h  |  29 +++++++++++
>>   hw/s390x/s390-pci-inst.c | 129 +++++++++++++++++++++++++++++++++++++++++++++--
>>   hw/s390x/s390-pci-inst.h |   1 +
>>   4 files changed, 159 insertions(+), 4 deletions(-)
>>
> 
>> +static void fmb_update(void *opaque)
>> +{
>> +    S390PCIBusDevice *pbdev = opaque;
>> +    int64_t t = qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL);
>> +    int i;
>> +
>> +    /* Update U bit */
>> +    pbdev->fmb.last_update *= 2;
>> +    pbdev->fmb.last_update |= UPDATE_U_BIT;
>> +    if (fmb_do_update(pbdev, offsetof(ZpciFmb, last_update),
>> +                      pbdev->fmb.last_update, 8)) {
>> +        return;
>> +    }
>> +
>> +    /* Update FMB sample count */
>> +    if (fmb_do_update(pbdev, offsetof(ZpciFmb, sample),
>> +                      pbdev->fmb.sample++, 4)) {
>> +        return;
>> +    }
>> +
>> +    /* Update FMB counters */
>> +    for (i = 0; i < ZPCI_FMB_CNT_MAX; i++) {
>> +        if (fmb_do_update(pbdev, offsetof(ZpciFmb, counter[i]),
>> +                          pbdev->fmb.counter[i], 8)) {
>> +            return;
>> +        }
>> +    }
>> +
>> +    /* Clear U bit and update the time */
>> +    pbdev->fmb.last_update = time2tod(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
>> +    pbdev->fmb.last_update *= 2;
>> +    if (fmb_do_update(pbdev, offsetof(ZpciFmb, last_update),
>> +                      pbdev->fmb.last_update, 8)) {
>> +        return;
>> +    }
>> +    timer_mod(pbdev->fmb_timer, t + DEFAULT_MUI);
>> +}
>> +
> 
> Might be better to use sizeof() instead of hard-coded values when
> calling fmb_do_update()?
> 
> Otherwise, looks good.
> 

OK, thanks, I send hopefully the last version with commit message 
corrected and sizeof instead of hard-coded values.

Regards,
Pierre


-- 
Pierre Morel
Linux/KVM/QEMU in Böblingen - Germany