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Message-ID: <20220524180241.GY1343366@nvidia.com>
Date: Tue, 24 May 2022 15:02:41 -0300
From: Jason Gunthorpe <jgg@...dia.com>
To: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: iommu@...ts.linux-foundation.org,
LKML <linux-kernel@...r.kernel.org>, dmaengine@...r.kernel.org,
Joerg Roedel <joro@...tes.org>,
David Woodhouse <dwmw2@...radead.org>,
Jean-Philippe Brucker <jean-philippe@...aro.com>,
Lu Baolu <baolu.lu@...ux.intel.com>,
Christoph Hellwig <hch@...radead.org>, vkoul@...nel.org,
robin.murphy@....com, will@...nel.org, Yi Liu <yi.l.liu@...el.com>,
Dave Jiang <dave.jiang@...el.com>,
"Tian, Kevin" <kevin.tian@...el.com>,
Raj Ashok <ashok.raj@...el.com>,
Eric Auger <eric.auger@...hat.com>
Subject: Re: [PATCH v4 3/6] iommu/vt-d: Implement domain ops for
attach_dev_pasid
On Tue, May 24, 2022 at 09:12:35AM -0700, Jacob Pan wrote:
> Hi Jason,
>
> On Tue, 24 May 2022 10:51:35 -0300, Jason Gunthorpe <jgg@...dia.com> wrote:
>
> > On Wed, May 18, 2022 at 11:21:17AM -0700, Jacob Pan wrote:
> > > On VT-d platforms with scalable mode enabled, devices issue DMA requests
> > > with PASID need to attach PASIDs to given IOMMU domains. The attach
> > > operation involves the following:
> > > - Programming the PASID into the device's PASID table
> > > - Tracking device domain and the PASID relationship
> > > - Managing IOTLB and device TLB invalidations
> > >
> > > This patch add attach_dev_pasid functions to the default domain ops
> > > which is used by DMA and identity domain types. It could be extended to
> > > support other domain types whenever necessary.
> > >
> > > Signed-off-by: Lu Baolu <baolu.lu@...ux.intel.com>
> > > Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> > > drivers/iommu/intel/iommu.c | 72 +++++++++++++++++++++++++++++++++++--
> > > 1 file changed, 70 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> > > index 1c2c92b657c7..75615c105fdf 100644
> > > +++ b/drivers/iommu/intel/iommu.c
> > > @@ -1556,12 +1556,18 @@ static void __iommu_flush_dev_iotlb(struct
> > > device_domain_info *info, u64 addr, unsigned int mask)
> > > {
> > > u16 sid, qdep;
> > > + ioasid_t pasid;
> > >
> > > if (!info || !info->ats_enabled)
> > > return;
> > >
> > > sid = info->bus << 8 | info->devfn;
> > > qdep = info->ats_qdep;
> > > + pasid = iommu_get_pasid_from_domain(info->dev,
> > > &info->domain->domain);
> >
> > No, a simgple domain can be attached to multiple pasids, all need to
> > be flushed.
> >
> Here is device TLB flush, why would I want to flush PASIDs other than my
> own device attached?
Again, a domain can be attached to multiple PASID's *on the same
device*
The idea that there is only one PASID per domain per device is not
right.
Jason
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