Re: [PATCH v4 1/2] hisi_acc_vfio_pci: fix NULL dereference in reset_prepare on PF passthrough

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] vfio/hisilicon: unprivileged userspace can spam kernel log via VFIO_DEVICE_RESET
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commit 232c524b0aed2e92588a217b15d2d609373f3ea0
Author: Longfang Liu <liulongfang@huawei.com>

hisi_acc_vfio_pci: fix NULL dereference in reset_prepare on PF passthrough

This commit fixes a NULL pointer dereference in the PCI error handler by
checking for migration support at the entry of reset_prepare() and
aer_reset_done(). It also properly clears the set_reset_flag in
aer_reset_done() and updates the VF checking logic in the probe function.

> diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> index 86362ec424a50..8ff69c8d1ff71 100644
> --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> @@ -1154,9 +1154,14 @@ static void hisi_acc_vf_pci_reset_prepare(struct pci_dev *pdev)
>  {
>  	struct hisi_acc_vf_core_device *hisi_acc_vdev = hisi_acc_drvdata(pdev);
>  	struct hisi_qm *qm = hisi_acc_vdev->pf_qm;
> -	struct device *dev = &qm->pdev->dev;
> +	struct device *dev = &pdev->dev;
>  	u32 delay = 0;
>  
> +	if (!hisi_acc_vdev->core_device.vdev.mig_ops) {
> +		dev_err(dev, "device not support migration\n");

[Severity: Medium]
Could this dev_err() be used by an unprivileged user or guest VM to spam the
kernel log?

Since a non-migratable VFIO device (like a PF or older VF) is a valid state,
an unprivileged user repeatedly invoking the VFIO_DEVICE_RESET ioctl might
trigger this path continuously through pci_reset_function(). 

Should this be changed to a debug log, be rate-limited, or return silently
to prevent potential denial of service via dmesg flooding?

> +		return;
> +	}
> +
>  	/* All reset requests need to be queued for processing */

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Sashiko AI review · https://sashiko.dev/#/patchset/20260918084244.1485837-1-liulongfang@huawei.com?part=1