Re: [PATCH v3 2/3] hisi_acc_vfio_pci: clear set_reset_flag after reset completed

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Incomplete fix: `set_reset_flag` is not cleared on the error path when `qm` or `qm->io_base` is NULL.
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commit 20e8953675b36be7d8bfc2a18cb44431bd40084a
Author: Longfang Liu <liulongfang@huawei.com>

hisi_acc_vfio_pci: clear set_reset_flag after reset completed

This patch attempts to make every reset cycle self-contained by clearing
set_reset_flag during aer_reset_done. It addresses an issue where a stale
latch could prematurely release a lock owned by another agent during a
reset timeout.

> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index e95d0ab0f11ab..4abed2e49986f 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -1180,10 +1180,12 @@ static void hisi_acc_vf_pci_aer_reset_done(struct pci_dev *pdev)
>  	struct hisi_qm *qm = hisi_acc_vdev->pf_qm;
>  
>  	if (hisi_acc_vdev->set_reset_flag) {
> -		if (qm && qm->io_base)
> +		if (qm && qm->io_base) {
>  			clear_bit(QM_RESETTING, &qm->misc_ctl);
> -		else
> +			hisi_acc_vdev->set_reset_flag = false;
> +		} else {
>  			dev_err(&pdev->dev, "PF QM not available for reset done\n");
> +		}

[Severity: High]
Does this leave set_reset_flag persistently set if qm or qm->io_base
evaluates to false?

If agent A sets set_reset_flag to true and encounters an unavailable PF QM
during hisi_acc_vf_pci_aer_reset_done(), the flag will remain true.

Later, if agent B holds the QM_RESETTING lock and agent A attempts another
reset that times out, could agent A's aer_reset_done() see the stale true
flag and prematurely clear agent B's lock if the QM has since become
available?

Should set_reset_flag be cleared unconditionally in this function, regardless
of whether the PF QM is currently available?

>  	}
>  
>  	if (!hisi_acc_vdev->core_device.vdev.mig_ops)

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Sashiko AI review · https://sashiko.dev/#/patchset/20260831090951.844569-1-liulongfang@huawei.com?part=2