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Date:   Tue, 22 Nov 2022 13:53:27 +0000
From:   Jonathan Cameron <Jonathan.Cameron@Huawei.com>
To:     Yicong Yang <yangyicong@huawei.com>
CC:     <mathieu.poirier@linaro.org>, <suzuki.poulose@arm.com>,
        <linux-kernel@vger.kernel.org>,
        <alexander.shishkin@linux.intel.com>, <helgaas@kernel.org>,
        <linux-pci@vger.kernel.org>, <prime.zeng@huawei.com>,
        <linuxarm@huawei.com>, Yicong Yang <yangyicong@hisilicon.com>
Subject: Re: [PATCH 1/2] hwtracing: hisi_ptt: Only add the supported devices
 to the filters list
Message-ID: <20221122135327.000004d8@Huawei.com>
In-Reply-To: <20221122120209.25682-1-yangyicong@huawei.com>
References: <20221122120209.25682-1-yangyicong@huawei.com>
Organization: Huawei Technologies Research and Development (UK) Ltd.
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On Tue, 22 Nov 2022 20:02:08 +0800
Yicong Yang <yangyicong@huawei.com> wrote:

> From: Yicong Yang <yangyicong@hisilicon.com>
> 
> The PTT device can only support the devices on the same PCIe core,
> within BDF range [lower_bdf, upper_bdf]. It's not correct to assume
> the devices on the root bus are from the same PCIe core, there are
> cases that root ports from different PCIe core are sharing the same
> bus. So add the checking when initialize the filters list.
> 
> Fixes: ff0de066b463 ("hwtracing: hisi_ptt: Add trace function support for HiSilicon PCIe Tune and Trace device")
> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>

Make sense to me.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

> ---
>  drivers/hwtracing/ptt/hisi_ptt.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
> index 5d5526aa60c4..30f1525639b5 100644
> --- a/drivers/hwtracing/ptt/hisi_ptt.c
> +++ b/drivers/hwtracing/ptt/hisi_ptt.c
> @@ -356,8 +356,18 @@ static int hisi_ptt_register_irq(struct hisi_ptt *hisi_ptt)
>  
>  static int hisi_ptt_init_filters(struct pci_dev *pdev, void *data)
>  {
> +	struct pci_dev *root_port = pcie_find_root_port(pdev);
>  	struct hisi_ptt_filter_desc *filter;
>  	struct hisi_ptt *hisi_ptt = data;
> +	u32 port_devid;
> +
> +	if (!root_port)
> +		return 0;
> +
> +	port_devid = PCI_DEVID(root_port->bus->number, root_port->devfn);
> +	if (port_devid < hisi_ptt->lower_bdf ||
> +	    port_devid > hisi_ptt->upper_bdf)
> +		return 0;
>  
>  	/*
>  	 * We won't fail the probe if filter allocation failed here. The filters