Re: [PATCH v7 11/11] iommu/vt-d: Add svm/sva invalidate function
From: Lu Baolu
Date: Fri Oct 25 2019 - 22:44:17 EST
Hi,
On 10/25/19 3:27 PM, Tian, Kevin wrote:
From: Jacob Pan [mailto:jacob.jun.pan@xxxxxxxxxxxxxxx]
Sent: Friday, October 25, 2019 3:55 AM
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.
specifically you may clarify that only invalidations related to
first-level page table is passed down, because it's guest
structure being bound to the first-level. other descriptors
are emulated or translated into other necessary operations.
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.
what is device ID? it's a bit confusing term here.
Signed-off-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Signed-off-by: Ashok Raj <ashok.raj@xxxxxxxxx>
Signed-off-by: Liu, Yi L <yi.l.liu@xxxxxxxxxxxxxxx>
---
drivers/iommu/intel-iommu.c | 170
++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 170 insertions(+)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index 5fab32fbc4b4..a73e76d6457a 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -5491,6 +5491,175 @@ 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 device where
guest
+ * could own the first level page tables without being shadowed by QEMU.
In
+ * this case there is no pass down unmap to the host IOMMU as a result of
unmap
+ * in the guest. Only invalidations are trapped and passed down.
+ * In all cases, only first level TLB invalidation (request with PASID) can be
+ * passed down, therefore we do not include IOTLB granularity for request
+ * without PASID (second level).
+ *
+ * For an 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_GRAN
U_NR] = {
+ /* PASID based IOTLB, support PASID selective and page selective */
+ {0, 1, 1},
+ /* PASID based dev TLBs, only support all PASIDs or single PASID */
+ {1, 1, 0},
I forgot previous discussion. is it necessary to pass down dev TLB invalidation
requests? Can it be handled by host iOMMU driver automatically?
On host SVA, when a memory is unmapped, driver callback will invalidate
dev IOTLB explicitly. So I guess we need to pass down it for guest case.
This is also required for guest iova over 1st level usage as far as can
see.
Best regards,
baolu
+ /* PASID cache */
+ {1, 1, 0}
+};
+
+const static u64
inv_type_granu_table[IOMMU_CACHE_INV_TYPE_NR][IOMMU_INV_GRAN
U_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, u64 *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;
+
+ 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 = 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) {
+ u64 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)
+ pasid = inv_info->pasid_info.pasid;
+ else if (inv_info->granularity == IOMMU_INV_GRANU_ADDR)
+ pasid = inv_info->addr_info.pasid;
+ else {
+ pr_err("Cannot find PASID for given cache type and
granularity\n");
+ break;
+ }
+
+ switch (BIT(cache_type)) {
+ case IOMMU_CACHE_INV_TYPE_IOTLB:
+ if (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,
mm_to_dma_pfn(inv_info->addr_info.addr),
+ pasid, size, granu, 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) {
+ qi_flush_dev_piotlb(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) {
+ 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_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;
+}
+#endif
+
static int intel_iommu_map(struct iommu_domain *domain,
unsigned long iova, phys_addr_t hpa,
size_t size, int iommu_prot)
@@ -6027,6 +6196,7 @@ 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
--
2.7.4