Messages in this thread | | | Date | Wed, 8 Dec 2021 09:22:55 -0400 | From | Jason Gunthorpe <> | Subject | Re: [PATCH 3/4] iommu/vt-d: Support PASID DMA for in-kernel usage |
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On Tue, Dec 07, 2021 at 05:47:13AM -0800, Jacob Pan wrote: > Between DMA requests with and without PASID (legacy), DMA mapping APIs > are used indiscriminately on a device. Therefore, we should always match > the addressing mode of the legacy DMA when enabling kernel PASID. > > This patch adds support for VT-d driver where the kernel PASID is > programmed to match RIDPASID. i.e. if the device is in pass-through, the > kernel PASID is also in pass-through; if the device is in IOVA mode, the > kernel PASID will also be using the same IOVA space. > > There is additional handling for IOTLB and device TLB flush w.r.t. the > kernel PASID. On VT-d, PASID-selective IOTLB flush is also on a > per-domain basis; whereas device TLB flush is per device. Note that > IOTLBs are used even when devices are in pass-through mode. ATS is > enabled device-wide, but the device drivers can choose to manage ATS at > per PASID level whenever control is available. > > Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com> > drivers/iommu/intel/iommu.c | 105 +++++++++++++++++++++++++++++++++++- > drivers/iommu/intel/pasid.c | 7 +++ > include/linux/intel-iommu.h | 3 +- > 3 files changed, 113 insertions(+), 2 deletions(-) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index 60253bc436bb..a2ef6b9e4bfc 100644 > +++ b/drivers/iommu/intel/iommu.c > @@ -1743,7 +1743,14 @@ static void domain_flush_piotlb(struct intel_iommu *iommu, > if (domain->default_pasid) > qi_flush_piotlb(iommu, did, domain->default_pasid, > addr, npages, ih); > - > + if (domain->kernel_pasid && !domain_type_is_si(domain)) { > + /* > + * REVISIT: we only do PASID IOTLB inval for FL, we could have SL > + * for PASID in the future such as vIOMMU PT. this doesn't get hit. > + */ > + qi_flush_piotlb(iommu, did, domain->kernel_pasid, > + addr, npages, ih); > + } > if (!list_empty(&domain->devices)) > qi_flush_piotlb(iommu, did, PASID_RID2PASID, addr, npages, ih); > } > @@ -5695,6 +5702,100 @@ static void intel_iommu_iotlb_sync_map(struct iommu_domain *domain, > } > } > > +static int intel_enable_pasid_dma(struct device *dev, u32 pasid) > +{
This seems like completely the wrong kind of op.
At the level of the iommu driver things should be iommu_domain centric
The op should be
int attach_dev_pasid(struct iommu_domain *domain, struct device *dev, ioasid_t pasid)
Where 'dev' purpose is to provide the RID
The iommu_domain passed in should be the 'default domain' ie the table used for on-demand mapping, or the passthrough page table.
> + struct intel_iommu *iommu = device_to_iommu(dev, NULL, NULL); > + struct device_domain_info *info;
I don't even want to know why an iommu driver is tracking its own per-device state. That seems like completely wrong layering.
Jason
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