Messages in this thread | | | From | "Tian, Kevin" <> | Subject | RE: [PATCH 1/1] iommu/vt-d: Omit devTLB invalidation requests when TES=0 | Date | Tue, 14 Nov 2023 03:14:32 +0000 |
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> From: Lu Baolu <baolu.lu@linux.intel.com> > Sent: Tuesday, November 14, 2023 9:11 AM > > The latest VT-d spec indicates that when remapping hardware is disabled > (TES=0 in Global Status Register), upstream ATS Invalidation Completion > requests are treated as UR (Unsupported Request). > > Consequently, the spec recommends in section 4.3 Handling of Device-TLB > Invalidations that software refrain from submitting any Device-TLB > invalidation requests when address remapping hardware is disabled. > > Verify address remapping hardware is enabled prior to submitting Device- > TLB invalidation requests. > > Fixes: 792fb43ce2c9 ("iommu/vt-d: Enable Intel IOMMU scalable mode by > default") > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > --- > drivers/iommu/intel/dmar.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c > index a3414afe11b0..23cb80d62a9a 100644 > --- a/drivers/iommu/intel/dmar.c > +++ b/drivers/iommu/intel/dmar.c > @@ -1522,6 +1522,15 @@ void qi_flush_dev_iotlb(struct intel_iommu > *iommu, u16 sid, u16 pfsid, > { > struct qi_desc desc; > > + /* > + * VT-d spec, section 4.3: > + * > + * Software is recommended to not submit any Device-TLB > invalidation > + * requests while address remapping hardware is disabled. > + */ > + if (!(iommu->gcmd & DMA_GCMD_TE)) > + return; > +
Is it a valid case to see such request when the iommu is disabled? If not then let's add a WARN.
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