Re: [PATCH 18/18] iommu/vt-d: Add svm/sva invalidate function

Andriy Shevchenko
2019-04-09T14:57:12Z

On Mon, Apr 08, 2019 at 04:59:33PM -0700, 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.

> +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 granu;
> + u64 size;
> +
> + if (!inv_info || !dmar_domain ||
> + inv_info->version != IOMMU_CACHE_INVALIDATE_INFO_VERSION_1)
> + return -EINVAL;
> +
> + iommu = device_to_iommu(dev, &bus, &devfn);
> + if (!iommu)
> + return -ENODEV;
> +

> + if (!dev || !dev_is_pci(dev))
> + return -ENODEV;

How dev is used in above call? Can be dev NULL there optional and give non-NULL
iommu?

> + switch (1 << cache_type) {

BIT() ?

> + case IOMMU_CACHE_INV_TYPE_IOTLB:
> + if (size && (inv_info->addr_info.addr & ((1 << (VTD_PAGE_SHIFT + size)) - 1))) {

BIT() ?

> + 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, mm_to_dma_pfn(inv_info->addr_info.addr),
> + inv_info->addr_info.pasid,
> + size, granu);
> +
> + /*
> + * Always flush device IOTLB if ATS is enabled since guest
> + * vIOMMU exposes CM = 1, no device IOTLB flush will be passed
> + * down. REVISIT: cannot assume Linux guest
> + */
> + if (info->ats_enabled) {
> + qi_flush_dev_piotlb(iommu, sid, info->pfsid,
> + inv_info->addr_info.pasid, info->ats_qdep,
> + inv_info->addr_info.addr, size,
> + granu);
> + }
> + break;
> + case IOMMU_CACHE_INV_TYPE_DEV_IOTLB:
> + if (info->ats_enabled) {
> + qi_flush_dev_piotlb(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");
> +
> + break;
> + case IOMMU_CACHE_INV_TYPE_PASID:
> + qi_flush_pasid_cache(iommu, did, granu, inv_info->pasid);
> +
> + 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;
> +}

--
With Best Regards,
Andy Shevchenko