linux-kernel - Re: [PATCH v2 02/16] iommu/vt-d: add bind_pasid

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Date:   Tue, 10 Oct 2017 15:21:20 +0200
From:   Joerg Roedel <joro@...tes.org>
To:     Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc:     iommu@...ts.linux-foundation.org,
        LKML <linux-kernel@...r.kernel.org>,
        David Woodhouse <dwmw2@...radead.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Rafael Wysocki <rafael.j.wysocki@...el.com>,
        Jean-Philippe Brucker <jean-philippe.brucker@....com>,
        "Liu, Yi L" <yi.l.liu@...el.com>,
        Lan Tianyu <tianyu.lan@...el.com>,
        "Tian, Kevin" <kevin.tian@...el.com>,
        Raj Ashok <ashok.raj@...el.com>,
        Alex Williamson <alex.williamson@...hat.com>, Liu@...tes.org,
        Yi L <yi.l.liu@...ux.intel.com>
Subject: Re: [PATCH v2 02/16] iommu/vt-d: add bind_pasid_table function

On Thu, Oct 05, 2017 at 04:03:30PM -0700, Jacob Pan wrote:
> +	pdev = to_pci_dev(dev);
> +	if (!pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_PRI))
> +		return -EINVAL;
> +	sid = PCI_DEVID(bus, devfn);

Okay, you search for the PRI capability ...
> +
> +	info = dev->archdata.iommu;
> +	if (!info || !info->pasid_supported) {
> +		dev_err(dev, "No PASID support\n");
> +		ret = -EINVAL;
> +		goto out;
> +	}
> +	if (!info->pasid_enabled) {
> +		ret = pci_enable_pasid(pdev, info->pasid_supported & ~1);
> +		if (ret)
> +			goto out;

... and you enable PASID in bind_pasid_table() ...


> +	/*
> +	 * REVISIT: we might want to clear the PASID table pointer
> +	 * as part of context clear operation. Currently, it leaves
> +	 * stale data but should be ignored by hardware since PASIDE
> +	 * is clear.
> +	 */
> +	/* ATS will be reenabled when remapping is restored */
> +	pci_disable_ats(to_pci_dev(dev));

.. while you disable ATS in unbind_pasid_table(). Where does this
asymmetry come from?

>  #define CONTEXT_DINVE		(1ULL << 8)
>  #define CONTEXT_PRS		(1ULL << 9)
> +#define CONTEXT_NESTE		(1ULL << 10)

Missing 'D' at the end?