From: Christoph Hellwig <hch@infradead.org>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
Alex Williamson <alex.williamson@redhat.com>,
Raj Ashok <ashok.raj@intel.com>,
David Woodhouse <dwmw2@infradead.org>,
LKML <linux-kernel@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
iommu@lists.linux-foundation.org,
Jean-Philippe Brucker <jean-philippe@linaro.com>,
Jonathan Cameron <jic23@kernel.org>
Subject: Re: [PATCH v13 4/8] iommu/vt-d: Add bind guest PASID support
Date: Wed, 13 May 2020 22:59:30 -0700 [thread overview]
Message-ID: <20200514055930.GD22388@infradead.org> (raw)
In-Reply-To: <1589410909-38925-5-git-send-email-jacob.jun.pan@linux.intel.com>
> + if (dev_is_pci(dev)) {
> + /* VT-d supports devices with full 20 bit PASIDs only */
> + if (pci_max_pasids(to_pci_dev(dev)) != PASID_MAX)
> + return -EINVAL;
> + } else {
> + return -ENOTSUPP;
> + }
This looks strange. Why not:
if (!dev_is_pci(dev)) {
return -ENOTSUPP;
/* VT-d supports devices with full 20 bit PASIDs only */
if (pci_max_pasids(to_pci_dev(dev)) != PASID_MAX)
return -EINVAL;
> + for_each_svm_dev(sdev, svm, dev) {
> + /*
> + * For devices with aux domains, we should allow multiple
> + * bind calls with the same PASID and pdev.
> + */
> + if (iommu_dev_feature_enabled(dev, IOMMU_DEV_FEAT_AUX)) {
> + sdev->users++;
> + } else {
> + dev_warn_ratelimited(dev, "Already bound with PASID %u\n",
> + svm->pasid);
> + ret = -EBUSY;
> + }
> + goto out;
Is this intentionally a for loop that jumps out of the loop after
the first device?
> + /*
> + * PASID table is per device for better security. Therefore, for
> + * each bind of a new device even with an existing PASID, we need to
> + * call the nested mode setup function here.
> + */
> + spin_lock(&iommu->lock);
> + ret = intel_pasid_setup_nested(iommu,
> + dev,
> + (pgd_t *)data->gpgd,
> + data->hpasid,
> + &data->vtd,
> + dmar_domain,
> + data->addr_width);
Why not:
et = intel_pasid_setup_nested(iommu, dev, (pgd_t *)data->gpgd,
data->hpasid, &data->vtd, dmar_domain,
data->addr_width);
?
> + for_each_svm_dev(sdev, svm, dev) {
> + ret = 0;
...
> + break;
> + }
Same only looks at the first device style. Why dos it only care about
the first device? That needs at least a comment, and probably a
first_svm_dev or so heper to make it explicit.
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next prev parent reply other threads:[~2020-05-14 5:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-13 23:01 [PATCH v13 0/8] Nested Shared Virtual Address (SVA) VT-d support Jacob Pan
2020-05-13 23:01 ` [PATCH v13 1/8] iommu/vt-d: Move domain helper to header Jacob Pan
2020-05-13 23:01 ` [PATCH v13 2/8] iommu/vt-d: Use a helper function to skip agaw for SL Jacob Pan
2020-05-14 5:51 ` Christoph Hellwig
2020-05-14 15:20 ` Jacob Pan
2020-05-13 23:01 ` [PATCH v13 3/8] iommu/vt-d: Add nested translation helper function Jacob Pan
2020-05-14 5:54 ` Christoph Hellwig
2020-05-14 15:31 ` Jacob Pan
2020-05-13 23:01 ` [PATCH v13 4/8] iommu/vt-d: Add bind guest PASID support Jacob Pan
2020-05-14 5:59 ` Christoph Hellwig [this message]
2020-05-14 15:57 ` Jacob Pan
2020-05-15 1:01 ` Lu Baolu
2020-05-16 6:02 ` Lu Baolu
2020-05-13 23:01 ` [PATCH v13 5/8] iommu/vt-d: Support flushing more translation cache types Jacob Pan
2020-05-13 23:01 ` [PATCH v13 6/8] iommu/vt-d: Add svm/sva invalidate function Jacob Pan
2020-05-13 23:01 ` [PATCH v13 7/8] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2020-05-13 23:01 ` [PATCH v13 8/8] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2020-05-16 6:31 ` [PATCH v13 0/8] Nested Shared Virtual Address (SVA) VT-d support Lu Baolu
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