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Message-ID: <20230403145458.5c30d5c6@jacob-builder>
Date: Mon, 3 Apr 2023 14:54:58 -0700
From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
To: Baolu Lu <baolu.lu@...ux.intel.com>
Cc: LKML <linux-kernel@...r.kernel.org>, iommu@...ts.linux.dev,
Robin Murphy <robin.murphy@....com>,
Jason Gunthorpe <jgg@...dia.com>,
Joerg Roedel <joro@...tes.org>, dmaengine@...r.kernel.org,
vkoul@...nel.org, Will Deacon <will@...nel.org>,
David Woodhouse <dwmw2@...radead.org>,
Raj Ashok <ashok.raj@...el.com>,
"Tian, Kevin" <kevin.tian@...el.com>, Yi Liu <yi.l.liu@...el.com>,
"Yu, Fenghua" <fenghua.yu@...el.com>,
Dave Jiang <dave.jiang@...el.com>,
Tony Luck <tony.luck@...el.com>,
"Zanussi, Tom" <tom.zanussi@...el.com>,
jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH v3 7/7] dmaengine/idxd: Re-enable kernel workqueue under
DMA API
Hi Baolu,
On Sat, 1 Apr 2023 21:39:32 +0800, Baolu Lu <baolu.lu@...ux.intel.com>
wrote:
> On 2023/4/1 7:11, Jacob Pan wrote:
> > static void idxd_disable_system_pasid(struct idxd_device *idxd)
> > {
> > + struct pci_dev *pdev = idxd->pdev;
> > + struct device *dev = &pdev->dev;
> > + struct iommu_domain *domain;
> > + union gencfg_reg gencfg;
> > +
> > + domain = iommu_get_domain_for_dev(dev);
> > + if (!domain || domain->type == IOMMU_DOMAIN_BLOCKED)
> > + return;
>
> Out of curiosity, why do you need to check the domain type? And, in
> which case could the domain for the device be changed to a blocking one?
>
> Once a driver is bound to the device, the driver "owns" the DMA of the
> device. No one else could change the domain except the driver itself.
nothing particular just for precaution, I can drop the check or add a
warn_on.
> > +
> > + iommu_detach_device_pasid(domain, dev, idxd->pasid);
> > + iommu_free_global_pasid(idxd->pasid);
> >
> > - iommu_sva_unbind_device(idxd->sva);
> > + gencfg.bits = ioread32(idxd->reg_base + IDXD_GENCFG_OFFSET);
> > + gencfg.user_int_en = 0;
> > + iowrite32(gencfg.bits, idxd->reg_base + IDXD_GENCFG_OFFSET);
> > idxd->sva = NULL;
> > + idxd->pasid = IOMMU_PASID_INVALID;
> > }
>
> Best regards,
> baolu
Thanks,
Jacob
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