Re: [PATCH V10 08/11] iommu/vt-d: Add svm/sva invalidate function

Auger Eric
2020-03-29T16:06:06Z

Hi Jacob,

On 3/21/20 12:27 AM, Jacob Pan wrote:
> When Shared Virtual Address (SVA) is enabled for a guest OS via
> vIOMMU, we need to provide invalidation support at IOMMU API and driver
> level. This patch adds Intel VT-d specific function to implement
> iommu passdown invalidate API for shared virtual address.
>
> The use case is for supporting caching structure invalidation
> of assigned SVM capable devices. Emulated IOMMU exposes queue
> invalidation capability and passes down all descriptors from the guest
> to the physical IOMMU.
>
> The assumption is that guest to host device ID mapping should be
> resolved prior to calling IOMMU driver. Based on the device handle,
> host IOMMU driver can replace certain fields before submit to the
> invalidation queue.
>
> ---
> v7 review fixed in v10
> ---
>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> Signed-off-by: Liu, Yi L <yi.l.liu@intel.com>
> ---
> drivers/iommu/intel-iommu.c | 182 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 182 insertions(+)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index b1477cd423dd..a76afb0fd51a 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -5619,6 +5619,187 @@ static void intel_iommu_aux_detach_device(struct iommu_domain *domain,
> aux_domain_remove_dev(to_dmar_domain(domain), dev);
> }
>
> +/*
> + * 2D array for converting and sanitizing IOMMU generic TLB granularity to
> + * VT-d granularity. Invalidation is typically included in the unmap operation
> + * as a result of DMA or VFIO unmap. However, for assigned devices guest
> + * owns the first level page tables. Invalidations of translation caches in the
> + * guest are trapped and passed down to the host.
> + *
> + * vIOMMU in the guest will only expose first level page tables, therefore
> + * we do not include IOTLB granularity for request without PASID (second level).
> + *
> + * For example, to find the VT-d granularity encoding for IOTLB
> + * type and page selective granularity within PASID:
> + * X: indexed by iommu cache type
> + * Y: indexed by enum iommu_inv_granularity
> + * [IOMMU_CACHE_INV_TYPE_IOTLB][IOMMU_INV_GRANU_ADDR]
> + *
> + * Granu_map array indicates validity of the table. 1: valid, 0: invalid
> + *
> + */
> +const static int inv_type_granu_map[IOMMU_CACHE_INV_TYPE_NR][IOMMU_INV_GRANU_NR] = {
> + /*
> + * PASID based IOTLB invalidation: PASID selective (per PASID),
> + * page selective (address granularity)
> + */
> + {0, 1, 1},
> + /* PASID based dev TLBs, only support all PASIDs or single PASID */
> + {1, 1, 0},
> + /* PASID cache */
> + {1, 1, 0}
> +};
> +
> +const static int inv_type_granu_table[IOMMU_CACHE_INV_TYPE_NR][IOMMU_INV_GRANU_NR] = {
> + /* PASID based IOTLB */
> + {0, QI_GRAN_NONG_PASID, QI_GRAN_PSI_PASID},
> + /* PASID based dev TLBs */
> + {QI_DEV_IOTLB_GRAN_ALL, QI_DEV_IOTLB_GRAN_PASID_SEL, 0},
> + /* PASID cache */
> + {QI_PC_ALL_PASIDS, QI_PC_PASID_SEL, 0},
> +};
> +
> +static inline int to_vtd_granularity(int type, int granu, int *vtd_granu)
> +{
> + if (type >= IOMMU_CACHE_INV_TYPE_NR || granu >= IOMMU_INV_GRANU_NR ||
> + !inv_type_granu_map[type][granu])
> + return -EINVAL;
> +
> + *vtd_granu = inv_type_granu_table[type][granu];
> +
> + return 0;
> +}
> +
> +static inline u64 to_vtd_size(u64 granu_size, u64 nr_granules)
> +{
> + u64 nr_pages = (granu_size * nr_granules) >> VTD_PAGE_SHIFT;
> +
> + /* VT-d size is encoded as 2^size of 4K pages, 0 for 4k, 9 for 2MB, etc.
> + * IOMMU cache invalidate API passes granu_size in bytes, and number of
> + * granu size in contiguous memory.
> + */
> + return order_base_2(nr_pages);
> +}
> +
> +#ifdef CONFIG_INTEL_IOMMU_SVM
> +static int intel_iommu_sva_invalidate(struct iommu_domain *domain,
> + struct device *dev, struct iommu_cache_invalidate_info *inv_info)
> +{
> + struct dmar_domain *dmar_domain = to_dmar_domain(domain);
> + struct device_domain_info *info;
> + struct intel_iommu *iommu;
> + unsigned long flags;
> + int cache_type;
> + u8 bus, devfn;
> + u16 did, sid;
> + int ret = 0;
> + u64 size = 0;
> +
> + if (!inv_info || !dmar_domain ||
> + inv_info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
> + return -EINVAL;
> +
> + if (!dev || !dev_is_pci(dev))
> + return -ENODEV;
> +
> + iommu = device_to_iommu(dev, &bus, &devfn);
> + if (!iommu)
> + return -ENODEV;
> +
> + spin_lock_irqsave(&device_domain_lock, flags);
> + spin_lock(&iommu->lock);
> + info = iommu_support_dev_iotlb(dmar_domain, iommu, bus, devfn);
> + if (!info) {
> + ret = -EINVAL;
> + goto out_unlock;
> + }
> + did = dmar_domain->iommu_did[iommu->seq_id];
> + sid = PCI_DEVID(bus, devfn);
> +
> + /* Size is only valid in non-PASID selective invalidation */
> + if (inv_info->granularity != IOMMU_INV_GRANU_PASID)
> + size = to_vtd_size(inv_info->addr_info.granule_size,
> + inv_info->addr_info.nb_granules);
> +
> + for_each_set_bit(cache_type, (unsigned long *)&inv_info->cache, IOMMU_CACHE_INV_TYPE_NR) {
> + int granu = 0;
> + u64 pasid = 0;
> +
> + ret = to_vtd_granularity(cache_type, inv_info->granularity, &granu);
> + if (ret) {
> + pr_err("Invalid cache type and granu combination %d/%d\n", cache_type,
> + inv_info->granularity);
> + break;
> + }
> +
> + /* PASID is stored in different locations based on granularity */
> + if (inv_info->granularity == IOMMU_INV_GRANU_PASID &&
> + inv_info->pasid_info.flags & IOMMU_INV_PASID_FLAGS_PASID)
> + pasid = inv_info->pasid_info.pasid;
> + else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR &&
> + inv_info->addr_info.flags & IOMMU_INV_ADDR_FLAGS_PASID)
> + pasid = inv_info->addr_info.pasid;
> + else {
> + pr_err("Cannot find PASID for given cache type and granularity\n");
I don't get this error msg. In case of domain-selective invalidation,
PASID is not used so if I am not wrong you will end up here while there
is no issue.
> + break;
> + }
> +
> + switch (BIT(cache_type)) {
> + case IOMMU_CACHE_INV_TYPE_IOTLB:
> + if ((inv_info->granularity != IOMMU_INV_GRANU_PASID) &&
> + size && (inv_info->addr_info.addr & ((BIT(VTD_PAGE_SHIFT + size)) - 1))) {
> + pr_err("Address out of range, 0x%llx, size order %llu\n",
> + inv_info->addr_info.addr, size);
> + ret = -ERANGE;
> + goto out_unlock;
> + }
> +
> + qi_flush_piotlb(iommu, did,
> + pasid,
> + mm_to_dma_pfn(inv_info->addr_info.addr),
> + (granu == QI_GRAN_NONG_PASID) ? -1 : 1 << size,
> + inv_info->addr_info.flags & IOMMU_INV_ADDR_FLAGS_LEAF);
> +
> + /*
> + * Always flush device IOTLB if ATS is enabled since guest
> + * vIOMMU exposes CM = 1, no device IOTLB flush will be passed
> + * down.
> + */
> + if (info->ats_enabled) {
nit {} not requested
> + qi_flush_dev_iotlb_pasid(iommu, sid, info->pfsid,
> + pasid, info->ats_qdep,
> + inv_info->addr_info.addr, size,
> + granu);
> + }
> + break;
> + case IOMMU_CACHE_INV_TYPE_DEV_IOTLB:
> + if (info->ats_enabled) {
nit {} not requested
> + qi_flush_dev_iotlb_pasid(iommu, sid, info->pfsid,
> + inv_info->addr_info.pasid, info->ats_qdep,
> + inv_info->addr_info.addr, size,
> + granu);
> + } else
> + pr_warn("Passdown device IOTLB flush w/o ATS!\n");
> +
nit: extra line
> + break;
> + case IOMMU_CACHE_INV_TYPE_PASID:
> + qi_flush_pasid_cache(iommu, did, granu, inv_info->pasid_info.pasid);
> +
nit: extra line
> + break;
> + default:
> + dev_err(dev, "Unsupported IOMMU invalidation type %d\n",
> + cache_type);
> + ret = -EINVAL;
> + }
> + }
> +out_unlock:
> + spin_unlock(&iommu->lock);
> + spin_unlock_irqrestore(&device_domain_lock, flags);
> +
> + return ret;
> +}
> +#endif
> +
> static int intel_iommu_map(struct iommu_domain *domain,
> unsigned long iova, phys_addr_t hpa,
> size_t size, int iommu_prot, gfp_t gfp)
> @@ -6204,6 +6385,7 @@ const struct iommu_ops intel_iommu_ops = {
> .is_attach_deferred = intel_iommu_is_attach_deferred,
> .pgsize_bitmap = INTEL_IOMMU_PGSIZES,
> #ifdef CONFIG_INTEL_IOMMU_SVM
> + .cache_invalidate = intel_iommu_sva_invalidate,
> .sva_bind_gpasid = intel_svm_bind_gpasid,
> .sva_unbind_gpasid = intel_svm_unbind_gpasid,
> #endif
>
Thanks

Eric