linux-kernel - Re: [PATCH 2/3] iommu: amd: Add support for RMP_PAGE_FAULT and RMP_HW

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Date:   Fri, 18 Sep 2020 11:31:18 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Suravee Suthikulpanit <suravee.suthikulpanit@....com>
Cc:     linux-kernel@...r.kernel.org, iommu@...ts.linux-foundation.org,
        Jon.Grimm@....com, brijesh.singh@....com
Subject: Re: [PATCH 2/3] iommu: amd: Add support for RMP_PAGE_FAULT and
 RMP_HW_ERR

Hi Suravee,

On Wed, Sep 16, 2020 at 01:55:48PM +0000, Suravee Suthikulpanit wrote:
> +static void amd_iommu_report_rmp_hw_error(volatile u32 *event)
> +{
> +	struct pci_dev *pdev;
> +	struct iommu_dev_data *dev_data = NULL;
> +	int devid     = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK;
> +	int vmg_tag   = (event[1]) & 0xFFFF;
> +	int flags     = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK;
> +	u64 spa       = ((u64)event[3] << 32) | (event[2] & 0xFFFFFFF8);

Please write this as:

	struct iommu_dev_data *dev_data = NULL;
	int devid, vmg_tag, flags;
	struct pci_dev *pdev;
	u64 spa;

	devid   = (event[0] >> EVENT_DEVID_SHIFT) & EVENT_DEVID_MASK;
	vmg_tag = (event[1]) & 0xFFFF;
	flags   = (event[1] >> EVENT_FLAGS_SHIFT) & EVENT_FLAGS_MASK;
	spa     = ((u64)event[3] << 32) | (event[2] & 0xFFFFFFF8);

Same applied the the next function.

> +
> +	pdev = pci_get_domain_bus_and_slot(0, PCI_BUS_NUM(devid),
> +					   devid & 0xff);
> +	if (pdev)
> +		dev_data = dev_iommu_priv_get(&pdev->dev);
> +
> +	if (dev_data && __ratelimit(&dev_data->rs)) {
> +		pci_err(pdev, "Event logged [RMP_HW_ERROR devid=0x%04x, vmg_tag=0x%04x, spa=0x%llx, flags=0x%04x]\n",
> +			devid, vmg_tag, spa, flags);

Printing the devid is not really needed here, no? Same issue in the next
function.

Regards,

	Joerg