Messages in this thread Patch in this message | | | Date | Thu, 15 Feb 2024 15:37:46 +0800 | Subject | Re: [PATCH v12 5/5] iommu/vt-d: improve ITE fault handling if target device isn't present | From | Baolu Lu <> |
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On 2/2/24 3:34 AM, Jason Gunthorpe wrote: > On Wed, Jan 31, 2024 at 02:21:20PM +0800, Baolu Lu wrote: >> An rbtree for IOMMU device data for the VT-d driver would be beneficial. >> It also benefits other paths of fault handling, such as the I/O page >> fault handling path, where it currently still relies on the PCI >> subsystem to convert a RID value into a pci_device structure. >> >> Given that such an rbtree would be helpful for multiple individual >> drivers that handle PCI devices, it seems valuable to implement it in >> the core? > rbtree is already supposed to be a re-usable library. > > There is already good helper support in rbtree to make things easy to > implement. I see arm hasn't used them yet, it should look something > like this:
I have posted a similar implementation for the vt-d driver here:
https://lore.kernel.org/linux-iommu/20240215072249.4465-1-baolu.lu@linux.intel.com/
Based on this implementation, only patches 1 and 2 are required. The last patch could be like below (code compiled but not tested, comments not changed yet):
diff --git a/drivers/iommu/intel/dmar.c b/drivers/iommu/intel/dmar.c index f9b63c2875f7..30a659a4d3ed 100644 --- a/drivers/iommu/intel/dmar.c +++ b/drivers/iommu/intel/dmar.c @@ -1272,6 +1272,7 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index) { u32 fault; int head, tail; + u64 iqe_err, ite_sid; struct q_inval *qi = iommu->qi; int shift = qi_shift(iommu);
@@ -1316,6 +1317,13 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index) tail = readl(iommu->reg + DMAR_IQT_REG); tail = ((tail >> shift) - 1 + QI_LENGTH) % QI_LENGTH;
+ /* + * SID field is valid only when the ITE field is Set in FSTS_REG + * see Intel VT-d spec r4.1, section 11.4.9.9 + */ + iqe_err = dmar_readq(iommu->reg + DMAR_IQER_REG); + ite_sid = DMAR_IQER_REG_ITESID(iqe_err); + writel(DMA_FSTS_ITE, iommu->reg + DMAR_FSTS_REG); pr_info("Invalidation Time-out Error (ITE) cleared\n");
@@ -1325,6 +1333,19 @@ static int qi_check_fault(struct intel_iommu *iommu, int index, int wait_index) head = (head - 2 + QI_LENGTH) % QI_LENGTH; } while (head != tail);
+ /* + * If got ITE, we need to check if the sid of ITE is the same as + * current ATS invalidation target device, if yes, don't try this + * request anymore if the target device isn't present. + * 0 value of ite_sid means old VT-d device, no ite_sid value. + */ + if (ite_sid) { + struct device *dev = device_rbtree_find(iommu, ite_sid); + + if (!dev || !pci_device_is_present(to_pci_dev(dev))) + return -ETIMEDOUT; + } + if (qi->desc_status[wait_index] == QI_ABORT) return -EAGAIN; } Best regards, baolu
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