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Subject: Re: [PATCH v5 3/3] crypto: hisilicon/qm - defining the device
 isolation strategy
To:     Greg KH <gregkh@linuxfoundation.org>
References: <20220708070820.43958-1-yekai13@huawei.com>
 <20220708070820.43958-4-yekai13@huawei.com> <YsfeMgbP+bxstf+7@kroah.com>
 <7cd8e1f3-b4a2-8aae-7b6e-99c5ceb5f17f@huawei.com>
CC:     <herbert@gondor.apana.org.au>, <linux-crypto@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <wangzhou1@hisilicon.com>
From:   "yekai(A)" <yekai13@huawei.com>
Message-ID: <4b34587e-562e-faeb-57c3-fd6793779107@huawei.com>
Date:   Sat, 23 Jul 2022 15:21:40 +0800
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On 2022/7/21 16:14, yekai(A) wrote:
>
>
> On 2022/7/8 15:35, Greg KH wrote:
>> On Fri, Jul 08, 2022 at 03:08:20PM +0800, Kai Ye wrote:
>>> Define the device isolation strategy by the device driver. The
>>> user configures a frequency value by uacce interface. If the
>>> slot reset frequency exceeds the value of setting for a certain
>>> period of time, the device will not be available in user space.
>>> The time window is one hour. The VF device use the PF device
>>> isolation strategy. All the hardware errors are processed by PF
>>> driver. This solution can be used for other drivers.
>>>
>>> Signed-off-by: Kai Ye <yekai13@huawei.com>
>>> ---
>>>  drivers/crypto/hisilicon/qm.c | 163 +++++++++++++++++++++++++++++++---
>>>  include/linux/hisi_acc_qm.h   |   9 ++
>>>  2 files changed, 160 insertions(+), 12 deletions(-)
>>>
>>> diff --git a/drivers/crypto/hisilicon/qm.c
>>> b/drivers/crypto/hisilicon/qm.c
>>> index ad83c194d664..8eb3b790a655 100644
>>> --- a/drivers/crypto/hisilicon/qm.c
>>> +++ b/drivers/crypto/hisilicon/qm.c
>>> @@ -417,6 +417,16 @@ struct hisi_qm_resource {
>>>      struct list_head list;
>>>  };
>>>
>>> +/**
>>> + * struct qm_hw_err - Structure describing the device errors
>>> + * @list: hardware error list
>>> + * @timestamp: timestamp when the error occurred
>>> + */
>>> +struct qm_hw_err {
>>> +    struct list_head list;
>>> +    unsigned long long timestamp;
>>> +};
>>> +
>>>  struct hisi_qm_hw_ops {
>>>      int (*get_vft)(struct hisi_qm *qm, u32 *base, u32 *number);
>>>      void (*qm_db)(struct hisi_qm *qm, u16 qn,
>>> @@ -3410,6 +3420,111 @@ static long hisi_qm_uacce_ioctl(struct
>>> uacce_queue *q, unsigned int cmd,
>>>      return 0;
>>>  }
>>>
>>> +/**
>>> + * qm_hw_err_isolate() - Try to isolate the uacce device with its VFs
>>> + * according to user's configuration of isolation strategy. Warning:
>>> this
>>> + * API should be called while there the users on this device are
>>> suspended
>>> + * by slot resetting preparation of PCI AER.
>>> + * @qm: the uacce device
>>> + */
>>> +static int qm_hw_err_isolate(struct hisi_qm *qm)
>>> +{
>>> +    struct qm_hw_err *err, *tmp, *hw_err;
>>> +    struct qm_err_isolate *isolate;
>>> +    u32 count = 0;
>>> +
>>> +    isolate = &qm->isolate_data;
>>> +
>>> +#define SECONDS_PER_HOUR    3600
>>> +
>>> +    /* All the hw errs are processed by PF driver */
>>> +    if (qm->uacce->is_vf || isolate->is_isolate ||
>>> +        !isolate->hw_err_isolate_hz)
>>> +        return 0;
>>> +
>>> +    hw_err = kzalloc(sizeof(*hw_err), GFP_ATOMIC);
>>
>> Why atomic?  What lock is held here?
>
> Atomic is not required. So use GFP_KERNEL.
>>
>>> +    if (!hw_err)
>>> +        return -ENOMEM;
>>> +
>>> +    mutex_lock(&isolate->isolate_lock);
>>> +    hw_err->timestamp = jiffies;
>>> +    list_for_each_entry_safe(err, tmp, &isolate->uacce_hw_errs, list) {
>>> +        if ((hw_err->timestamp - err->timestamp) / HZ >
>>> +            SECONDS_PER_HOUR) {
>>
>> No possiblity of wrapping the timestamp?
> I do not understand this suggestion, Can you show more detail in this
> suggestion?
>
>>
>>> +            list_del(&err->list);
>>> +            kfree(err);
>>> +        } else {
>>> +            count++;
>>> +        }
>>> +    }
>>> +    list_add(&hw_err->list, &isolate->uacce_hw_errs);
>>> +    mutex_unlock(&isolate->isolate_lock);
>>> +
>>> +    if (count >= isolate->hw_err_isolate_hz)
>>> +        isolate->is_isolate = true;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> +static void qm_hw_err_destroy(struct hisi_qm *qm)
>>> +{
>>> +    struct qm_hw_err *err, *tmp;
>>> +
>>> +    mutex_lock(&qm->isolate_data.isolate_lock);
>>> +    list_for_each_entry_safe(err, tmp,
>>> &qm->isolate_data.uacce_hw_errs, list) {
>>> +        list_del(&err->list);
>>> +        kfree(err);
>>> +    }
>>> +    mutex_unlock(&qm->isolate_data.isolate_lock);
>>> +}
>>> +
>>> +static enum uacce_dev_state hisi_qm_get_isolate_state(struct
>>> uacce_device *uacce)
>>> +{
>>> +    struct hisi_qm *qm = uacce->priv;
>>> +    struct hisi_qm *pf_qm;
>>> +
>>> +    if (uacce->is_vf)
>>> +        pf_qm = pci_get_drvdata(pci_physfn(qm->pdev));
>>> +    else
>>> +        pf_qm = qm;
>>> +
>>> +    return pf_qm->isolate_data.is_isolate ?
>>> +            UACCE_DEV_ISOLATE : UACCE_DEV_NORMAL;
>>> +}
>>> +
>>> +static int hisi_qm_isolate_strategy_write(struct uacce_device *uacce,
>>> +                      u32 freq)
>>> +{
>>> +    struct hisi_qm *qm = uacce->priv;
>>> +
>>> +    /* Must be set by PF */
>>> +    if (uacce->is_vf)
>>> +        return -EINVAL;
>>
>> But the value passed to you is not invalid, something else went wrong.
>> Are you sure this is the correct error?
> use EPERM instead of EINVAL.
>>
>>> +
>>> +    if (qm->isolate_data.is_isolate)
>>> +        return -EINVAL;
>>
>> Same here, why is this correct?
> use EPERM instead of EINVAL.
>>
>>> +
>>> +    qm->isolate_data.hw_err_isolate_hz = freq;
>>
>> No validation of the value passed to you?  It can be anything?
The range has been verified by the UACCE. So do not need to check again.

>>
>>> +
>>> +    /* After the policy is updated, need to reset the hardware err
>>> list */
>>> +    qm_hw_err_destroy(qm);
>>
>> No error checking?
> Due to the process is clean list. So no error checking is required.
>>
>> thanks,
>>
>> greg k-h
>> .
>>
>
> Thanks
>
> Kai
> .
>

Thanks

Kai