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Subject: Re: [PATCH v4 3/3] crypto: hisilicon/qm - defining the device
 isolation strategy
To:     Greg KH <gregkh@linuxfoundation.org>
References: <20220623061452.40732-1-yekai13@huawei.com>
 <20220623061452.40732-4-yekai13@huawei.com> <YrQs06SXaqwaoAOY@kroah.com>
CC:     <herbert@gondor.apana.org.au>, <linux-crypto@vger.kernel.org>,
        <linux-accelerators@lists.ozlabs.org>,
        <linux-kernel@vger.kernel.org>, <linuxarm@huawei.com>,
        <zhangfei.gao@linaro.org>, <wangzhou1@hisilicon.com>
From:   "yekai(A)" <yekai13@huawei.com>
Message-ID: <2f382104-927d-e25a-c03b-a4b0482008ff@huawei.com>
Date:   Mon, 27 Jun 2022 20:09:57 +0800
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On 2022/6/23 17:05, Greg KH wrote:
> On Thu, Jun 23, 2022 at 02:14:52PM +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.
>> This frequency is an abstract number of times that can be
>> considered to occur in a time window. The time window can be set
>> to one hour or one day. The VF device use the PF device isolation
>> strategy. All the hardware errors are processed by PF driver.
>>
>> Signed-off-by: Kai Ye <yekai13@huawei.com>
>> ---
>>  drivers/crypto/hisilicon/qm.c | 177 +++++++++++++++++++++++++++++++---
>>  include/linux/hisi_acc_qm.h   |   9 ++
>>  2 files changed, 174 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/crypto/hisilicon/qm.c b/drivers/crypto/hisilicon/qm.c
>> index ad83c194d664..f92cf20fc84e 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 of describes the device err
>> + * @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 +3420,125 @@ 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 || atomic_read(&isolate->is_isolate) ||
>> +	    !isolate->hw_err_isolate_hz)
>> +		return 0;
>> +
>> +	hw_err = kzalloc(sizeof(*hw_err), GFP_ATOMIC);
>> +	if (!hw_err)
>> +		return -ENOMEM;
>> +
>> +	mutex_lock(&isolate->isolate_lock);
>> +	hw_err->timestamp = jiffies;
>> +	list_for_each_entry_safe(err, tmp, &qm->uacce_hw_errs, list) {
>> +		if ((hw_err->timestamp - err->timestamp) / HZ >
>> +		    SECONDS_PER_HOUR) {
>> +			list_del(&err->list);
>> +			kfree(err);
>> +		} else {
>> +			count++;
>> +		}
>> +	}
>> +	list_add(&hw_err->list, &qm->uacce_hw_errs);
>> +	mutex_unlock(&isolate->isolate_lock);
>> +
>> +	if (count >= isolate->hw_err_isolate_hz)
>> +		atomic_set(&isolate->is_isolate, 1);
>
> Why is this an atomic value?  You can change it after it has been set,
> and it can be modified after it is read.  A normal 'bool' would work
> exactly the same.
>
>
Yes A normal 'bool' is good.
>
>> +
>> +	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->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 atomic_read(&pf_qm->isolate_data.is_isolate) ?
>> +			UACCE_DEV_ISOLATE : UACCE_DEV_NORMAL;
>> +}
>> +
>> +static int hisi_qm_isolate_strategy_write(struct uacce_device *uacce,
>> +					  const char *buf, size_t len)
>> +{
>> +	struct hisi_qm *qm = uacce->priv;
>> +	unsigned long val;
>> +
>> +#define MAX_ISOLATE_STRATEGY	65535
>
> What is this value?  Please document it better.
>

Specified maximum frequency, and will move this value to uacce.
>> +
>> +	/* Must be set by PF */
>> +	if (uacce->is_vf) {
>> +		dev_info(&qm->pdev->dev, "the isolation strategy must be set by PF.\n");
>
> Do not let userspace spam the kernel log for no good reason.
>
> And why is this an info?

delete it.
>
>> +		return -EINVAL;
>
> This looks like an error.
>
>> +	}
>> +
>> +	if (atomic_read(&qm->isolate_data.is_isolate))
>> +		return -EINVAL;
>
> What happens if this changes right after reading it?

It is meaningless to configure a count that has been isolated.
>
>> +
>> +	if (kstrtoul(buf, 0, &val) < 0)
>> +		return -EINVAL;
>> +
>> +	if (val > MAX_ISOLATE_STRATEGY)
>> +		return -EINVAL;
>> +
>> +	qm->isolate_data.hw_err_isolate_hz = val;
>> +
>> +	/* After the policy is updated, need to reset the hardware err list */
>> +	qm_hw_err_destroy(qm);
>> +
>> +	return 0;
>
> Don't you need to return the number of bytes read, not 0?
>
>> +}
>> +
>> +static int hisi_qm_isolate_strategy_read(struct uacce_device *uacce, char *buf)
>> +{
>> +	struct hisi_qm *qm = uacce->priv;
>> +	struct hisi_qm *pf_qm;
>> +	unsigned long val;
>> +
>> +	if (uacce->is_vf) {
>> +		pf_qm = pci_get_drvdata(pci_physfn(qm->pdev));
>> +		val = pf_qm->isolate_data.hw_err_isolate_hz;
>> +	} else {
>> +		val = qm->isolate_data.hw_err_isolate_hz;
>> +	}
>> +
>> +	return sysfs_emit(buf, "%lu\n", val);
>> +}
>> +
>>  static const struct uacce_ops uacce_qm_ops = {
>>  	.get_available_instances = hisi_qm_get_available_instances,
>>  	.get_queue = hisi_qm_uacce_get_queue,
>> @@ -3419,8 +3548,22 @@ static const struct uacce_ops uacce_qm_ops = {
>>  	.mmap = hisi_qm_uacce_mmap,
>>  	.ioctl = hisi_qm_uacce_ioctl,
>>  	.is_q_updated = hisi_qm_is_q_updated,
>> +	.get_isolate_state = hisi_qm_get_isolate_state,
>> +	.isolate_strategy_write = hisi_qm_isolate_strategy_write,
>> +	.isolate_strategy_read = hisi_qm_isolate_strategy_read,
>>  };
>>
>> +static void qm_remove_uacce(struct hisi_qm *qm)
>> +{
>> +	struct uacce_device *uacce = qm->uacce;
>> +
>> +	if (qm->use_sva) {
>> +		qm_hw_err_destroy(qm);
>> +		uacce_remove(uacce);
>> +		qm->uacce = NULL;
>> +	}
>> +}
>> +
>>  static int qm_alloc_uacce(struct hisi_qm *qm)
>>  {
>>  	struct pci_dev *pdev = qm->pdev;
>> @@ -3433,6 +3576,8 @@ static int qm_alloc_uacce(struct hisi_qm *qm)
>>  	};
>>  	int ret;
>>
>> +	INIT_LIST_HEAD(&qm->uacce_hw_errs);
>> +	mutex_init(&qm->isolate_data.isolate_lock);
>>  	ret = strscpy(interface.name, dev_driver_string(&pdev->dev),
>>  		      sizeof(interface.name));
>>  	if (ret < 0)
>> @@ -3446,8 +3591,7 @@ static int qm_alloc_uacce(struct hisi_qm *qm)
>>  		qm->use_sva = true;
>>  	} else {
>>  		/* only consider sva case */
>> -		uacce_remove(uacce);
>> -		qm->uacce = NULL;
>> +		qm_remove_uacce(qm);
>>  		return -EINVAL;
>>  	}
>>
>> @@ -5109,6 +5253,12 @@ static int qm_controller_reset_prepare(struct hisi_qm *qm)
>>  		return ret;
>>  	}
>>
>> +	if (qm->use_sva) {
>> +		ret = qm_hw_err_isolate(qm);
>> +		if (ret)
>> +			pci_err(pdev, "failed to isolate hw err!\n");
>> +	}
>> +
>>  	ret = qm_wait_vf_prepare_finish(qm);
>>  	if (ret)
>>  		pci_err(pdev, "failed to stop by vfs in soft reset!\n");
>> @@ -5436,19 +5586,25 @@ static int qm_controller_reset(struct hisi_qm *qm)
>>  	ret = qm_soft_reset(qm);
>>  	if (ret) {
>>  		pci_err(pdev, "Controller reset failed (%d)\n", ret);
>> -		qm_reset_bit_clear(qm);
>> -		return ret;
>> +		goto err_reset;
>>  	}
>>
>>  	ret = qm_controller_reset_done(qm);
>> -	if (ret) {
>> -		qm_reset_bit_clear(qm);
>> -		return ret;
>> -	}
>> +	if (ret)
>> +		goto err_reset;
>>
>>  	pci_info(pdev, "Controller reset complete\n");
>>
>>  	return 0;
>> +
>> +err_reset:
>> +	pci_err(pdev, "Controller reset failed (%d)\n", ret);
>> +	qm_reset_bit_clear(qm);
>> +
>> +	/* if resetting fails, isolate the device */
>> +	if (qm->use_sva && !qm->uacce->is_vf)
>> +		atomic_set(&qm->isolate_data.is_isolate, 1);
>> +	return ret;
>>  }
>>
>>  /**
>> @@ -6246,10 +6402,7 @@ int hisi_qm_init(struct hisi_qm *qm)
>>  err_free_qm_memory:
>>  	hisi_qm_memory_uninit(qm);
>>  err_alloc_uacce:
>> -	if (qm->use_sva) {
>> -		uacce_remove(qm->uacce);
>> -		qm->uacce = NULL;
>> -	}
>> +	qm_remove_uacce(qm);
>>  err_irq_register:
>>  	qm_irq_unregister(qm);
>>  err_pci_init:
>> diff --git a/include/linux/hisi_acc_qm.h b/include/linux/hisi_acc_qm.h
>> index 116e8bd68c99..44454150c205 100644
>> --- a/include/linux/hisi_acc_qm.h
>> +++ b/include/linux/hisi_acc_qm.h
>> @@ -271,6 +271,13 @@ struct hisi_qm_poll_data {
>>  	u16 *qp_finish_id;
>>  };
>>
>> +struct qm_err_isolate {
>> +	struct mutex isolate_lock;
>> +	/* user cfg freq which triggers isolation */
>> +	u32 hw_err_isolate_hz;
>> +	atomic_t is_isolate;
>
> Again, why is this an atomic value?

Yes, bool can be used.
>
> thanks,
>
> greg k-h
> .
>

thanks

Kai