RE: [PATCH v7 9/9] iommu/vt-d: Add iotlb flush for nested domain

Duan, Zhenzhong
2023-12-27T09:27:28Z

>-----Original Message-----
>From: Liu, Yi L <yi.l.liu@intel.com>
>Subject: [PATCH v7 9/9] iommu/vt-d: Add iotlb flush for nested domain
>
>From: Lu Baolu <baolu.lu@linux.intel.com>
>
>This implements the .cache_invalidate_user() callback to support iotlb
>flush for nested domain.
>
>Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>Co-developed-by: Yi Liu <yi.l.liu@intel.com>
>Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>---
> drivers/iommu/intel/nested.c | 116
>+++++++++++++++++++++++++++++++++++
> 1 file changed, 116 insertions(+)
>
>diff --git a/drivers/iommu/intel/nested.c b/drivers/iommu/intel/nested.c
>index b5a5563ab32c..c665e2647045 100644
>--- a/drivers/iommu/intel/nested.c
>+++ b/drivers/iommu/intel/nested.c
>@@ -73,9 +73,125 @@ static void intel_nested_domain_free(struct
>iommu_domain *domain)
> kfree(to_dmar_domain(domain));
> }
>
>+static void nested_flush_pasid_iotlb(struct intel_iommu *iommu,
>+ struct dmar_domain *domain, u64 addr,
>+ unsigned long npages, bool ih)
>+{
>+ u16 did = domain_id_iommu(domain, iommu);
>+ unsigned long flags;
>+
>+ spin_lock_irqsave(&domain->lock, flags);
>+ if (!list_empty(&domain->devices))
>+ qi_flush_piotlb(iommu, did, IOMMU_NO_PASID, addr,
>+ npages, ih, NULL);

Is it optimal to check if domain attached to iommu before trigger flush?
Or the check is redundant if intel_nested_flush_cache() is the only call site.

Thanks
Zhenzhong

>+ spin_unlock_irqrestore(&domain->lock, flags);
>+}
>+
>+static void nested_flush_dev_iotlb(struct dmar_domain *domain, u64 addr,
>+ unsigned mask, u32 *fault)
>+{
>+ struct device_domain_info *info;
>+ unsigned long flags;
>+ u16 sid, qdep;
>+
>+ spin_lock_irqsave(&domain->lock, flags);
>+ list_for_each_entry(info, &domain->devices, link) {
>+ if (!info->ats_enabled)
>+ continue;
>+ sid = info->bus << 8 | info->devfn;
>+ qdep = info->ats_qdep;
>+ qi_flush_dev_iotlb(info->iommu, sid, info->pfsid,
>+ qdep, addr, mask, fault);
>+ quirk_extra_dev_tlb_flush(info, addr, mask,
>+ IOMMU_NO_PASID, qdep);
>+ }
>+ spin_unlock_irqrestore(&domain->lock, flags);
>+}
>+
>+static void intel_nested_flush_cache(struct dmar_domain *domain, u64
>addr,
>+ unsigned long npages, u32 *error)
>+{
>+ struct iommu_domain_info *info;
>+ unsigned long i;
>+ unsigned mask;
>+ u32 fault = 0;
>+
>+ if (npages == U64_MAX)
>+ mask = 64 - VTD_PAGE_SHIFT;
>+ else
>+ mask = ilog2(__roundup_pow_of_two(npages));
>+
>+ xa_for_each(&domain->iommu_array, i, info) {
>+ nested_flush_pasid_iotlb(info->iommu, domain, addr,
>npages, 0);
>+
>+ if (domain->has_iotlb_device)
>+ continue;
>+
>+ nested_flush_dev_iotlb(domain, addr, mask, &fault);
>+ if (fault & (DMA_FSTS_ITE | DMA_FSTS_ICE))
>+ break;
>+ }
>+
>+ if (fault & DMA_FSTS_ICE)
>+ *error |= IOMMU_HWPT_INVALIDATE_VTD_S1_ICE;
>+ if (fault & DMA_FSTS_ITE)
>+ *error |= IOMMU_HWPT_INVALIDATE_VTD_S1_ITE;
>+}
>+
>+static int intel_nested_cache_invalidate_user(struct iommu_domain
>*domain,
>+ struct iommu_user_data_array
>*array)
>+{
>+ struct dmar_domain *dmar_domain = to_dmar_domain(domain);
>+ struct iommu_hwpt_vtd_s1_invalidate inv_entry;
>+ u32 processed = 0;
>+ int ret = 0;
>+ u32 index;
>+
>+ if (array->type != IOMMU_HWPT_INVALIDATE_DATA_VTD_S1) {
>+ ret = -EINVAL;
>+ goto out;
>+ }
>+
>+ for (index = 0; index < array->entry_num; index++) {
>+ ret = iommu_copy_struct_from_user_array(&inv_entry,
>array,
>+
> IOMMU_HWPT_INVALIDATE_DATA_VTD_S1,
>+ index, inv_error);
>+ if (ret)
>+ break;
>+
>+ if (inv_entry.flags & ~IOMMU_VTD_INV_FLAGS_LEAF) {
>+ ret = -EOPNOTSUPP;
>+ break;
>+ }
>+
>+ if (!IS_ALIGNED(inv_entry.addr, VTD_PAGE_SIZE) ||
>+ ((inv_entry.npages == U64_MAX) && inv_entry.addr)) {
>+ ret = -EINVAL;
>+ break;
>+ }
>+
>+ inv_entry.inv_error = 0;
>+ intel_nested_flush_cache(dmar_domain, inv_entry.addr,
>+ inv_entry.npages,
>&inv_entry.inv_error);
>+
>+ ret = iommu_respond_struct_to_user_array(array, index,
>+ (void *)&inv_entry,
>+ sizeof(inv_entry));
>+ if (ret)
>+ break;
>+
>+ processed++;
>+ }
>+
>+out:
>+ array->entry_num = processed;
>+ return ret;
>+}
>+
> static const struct iommu_domain_ops intel_nested_domain_ops = {
> .attach_dev = intel_nested_attach_dev,
> .free = intel_nested_domain_free,
>+ .cache_invalidate_user = intel_nested_cache_invalidate_user,
> };
>
> struct iommu_domain *intel_nested_domain_alloc(struct iommu_domain
>*parent,
>--
>2.34.1