From 90519b90539b16258d1d52b908b199f44877dc18 Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Mon, 13 Jun 2022 14:10:08 +0800 Subject: [PATCH] virtio-iommu: Add bypass mode support to assigned device Currently assigned devices can not work in virtio-iommu bypass mode. Guest driver fails to probe the device due to DMA failure. And the reason is because of lacking GPA -> HPA mappings when VM is created. Add a root container memory region to hold both bypass memory region and iommu memory region, so the switch between them is supported just like the implementation in virtual VT-d. Signed-off-by: Zhenzhong Duan Message-Id: <20220613061010.2674054-2-zhenzhong.duan@intel.com> Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/trace-events | 1 + hw/virtio/virtio-iommu.c | 115 ++++++++++++++++++++++++++++++- include/hw/virtio/virtio-iommu.h | 2 + 3 files changed, 116 insertions(+), 2 deletions(-) diff --git a/hw/virtio/trace-events b/hw/virtio/trace-events index ab8e095b73..20af2e7ebd 100644 --- a/hw/virtio/trace-events +++ b/hw/virtio/trace-events @@ -124,6 +124,7 @@ virtio_iommu_remap(const char *name, uint64_t virt_start, uint64_t virt_end, uin virtio_iommu_set_page_size_mask(const char *name, uint64_t old, uint64_t new) "mr=%s old_mask=0x%"PRIx64" new_mask=0x%"PRIx64 virtio_iommu_notify_flag_add(const char *name) "add notifier to mr %s" virtio_iommu_notify_flag_del(const char *name) "del notifier from mr %s" +virtio_iommu_switch_address_space(uint8_t bus, uint8_t slot, uint8_t fn, bool on) "Device %02x:%02x.%x switching address space (iommu enabled=%d)" # virtio-mem.c virtio_mem_send_response(uint16_t type) "type=%" PRIu16 diff --git a/hw/virtio/virtio-iommu.c b/hw/virtio/virtio-iommu.c index 2597e166f9..ff718107ee 100644 --- a/hw/virtio/virtio-iommu.c +++ b/hw/virtio/virtio-iommu.c @@ -69,6 +69,77 @@ static inline uint16_t virtio_iommu_get_bdf(IOMMUDevice *dev) return PCI_BUILD_BDF(pci_bus_num(dev->bus), dev->devfn); } +static bool virtio_iommu_device_bypassed(IOMMUDevice *sdev) +{ + uint32_t sid; + bool bypassed; + VirtIOIOMMU *s = sdev->viommu; + VirtIOIOMMUEndpoint *ep; + + sid = virtio_iommu_get_bdf(sdev); + + qemu_mutex_lock(&s->mutex); + /* need to check bypass before system reset */ + if (!s->endpoints) { + bypassed = s->config.bypass; + goto unlock; + } + + ep = g_tree_lookup(s->endpoints, GUINT_TO_POINTER(sid)); + if (!ep || !ep->domain) { + bypassed = s->config.bypass; + } else { + bypassed = ep->domain->bypass; + } + +unlock: + qemu_mutex_unlock(&s->mutex); + return bypassed; +} + +/* Return whether the device is using IOMMU translation. */ +static bool virtio_iommu_switch_address_space(IOMMUDevice *sdev) +{ + bool use_remapping; + + assert(sdev); + + use_remapping = !virtio_iommu_device_bypassed(sdev); + + trace_virtio_iommu_switch_address_space(pci_bus_num(sdev->bus), + PCI_SLOT(sdev->devfn), + PCI_FUNC(sdev->devfn), + use_remapping); + + /* Turn off first then on the other */ + if (use_remapping) { + memory_region_set_enabled(&sdev->bypass_mr, false); + memory_region_set_enabled(MEMORY_REGION(&sdev->iommu_mr), true); + } else { + memory_region_set_enabled(MEMORY_REGION(&sdev->iommu_mr), false); + memory_region_set_enabled(&sdev->bypass_mr, true); + } + + return use_remapping; +} + +static void virtio_iommu_switch_address_space_all(VirtIOIOMMU *s) +{ + GHashTableIter iter; + IOMMUPciBus *iommu_pci_bus; + int i; + + g_hash_table_iter_init(&iter, s->as_by_busptr); + while (g_hash_table_iter_next(&iter, NULL, (void **)&iommu_pci_bus)) { + for (i = 0; i < PCI_DEVFN_MAX; i++) { + if (!iommu_pci_bus->pbdev[i]) { + continue; + } + virtio_iommu_switch_address_space(iommu_pci_bus->pbdev[i]); + } + } +} + /** * The bus number is used for lookup when SID based operations occur. * In that case we lazily populate the IOMMUPciBus array from the bus hash @@ -213,6 +284,7 @@ static gboolean virtio_iommu_notify_map_cb(gpointer key, gpointer value, static void virtio_iommu_detach_endpoint_from_domain(VirtIOIOMMUEndpoint *ep) { VirtIOIOMMUDomain *domain = ep->domain; + IOMMUDevice *sdev = container_of(ep->iommu_mr, IOMMUDevice, iommu_mr); if (!ep->domain) { return; @@ -221,6 +293,7 @@ static void virtio_iommu_detach_endpoint_from_domain(VirtIOIOMMUEndpoint *ep) ep->iommu_mr); QLIST_REMOVE(ep, next); ep->domain = NULL; + virtio_iommu_switch_address_space(sdev); } static VirtIOIOMMUEndpoint *virtio_iommu_get_endpoint(VirtIOIOMMU *s, @@ -323,12 +396,39 @@ static AddressSpace *virtio_iommu_find_add_as(PCIBus *bus, void *opaque, trace_virtio_iommu_init_iommu_mr(name); + memory_region_init(&sdev->root, OBJECT(s), name, UINT64_MAX); + address_space_init(&sdev->as, &sdev->root, TYPE_VIRTIO_IOMMU); + + /* + * Build the IOMMU disabled container with aliases to the + * shared MRs. Note that aliasing to a shared memory region + * could help the memory API to detect same FlatViews so we + * can have devices to share the same FlatView when in bypass + * mode. (either by not configuring virtio-iommu driver or with + * "iommu=pt"). It will greatly reduce the total number of + * FlatViews of the system hence VM runs faster. + */ + memory_region_init_alias(&sdev->bypass_mr, OBJECT(s), + "system", get_system_memory(), 0, + memory_region_size(get_system_memory())); + memory_region_init_iommu(&sdev->iommu_mr, sizeof(sdev->iommu_mr), TYPE_VIRTIO_IOMMU_MEMORY_REGION, OBJECT(s), name, UINT64_MAX); - address_space_init(&sdev->as, - MEMORY_REGION(&sdev->iommu_mr), TYPE_VIRTIO_IOMMU); + + /* + * Hook both the containers under the root container, we + * switch between iommu & bypass MRs by enable/disable + * corresponding sub-containers + */ + memory_region_add_subregion_overlap(&sdev->root, 0, + MEMORY_REGION(&sdev->iommu_mr), + 0); + memory_region_add_subregion_overlap(&sdev->root, 0, + &sdev->bypass_mr, 0); + + virtio_iommu_switch_address_space(sdev); g_free(name); } return &sdev->as; @@ -342,6 +442,7 @@ static int virtio_iommu_attach(VirtIOIOMMU *s, uint32_t flags = le32_to_cpu(req->flags); VirtIOIOMMUDomain *domain; VirtIOIOMMUEndpoint *ep; + IOMMUDevice *sdev; trace_virtio_iommu_attach(domain_id, ep_id); @@ -375,6 +476,8 @@ static int virtio_iommu_attach(VirtIOIOMMU *s, QLIST_INSERT_HEAD(&domain->endpoint_list, ep, next); ep->domain = domain; + sdev = container_of(ep->iommu_mr, IOMMUDevice, iommu_mr); + virtio_iommu_switch_address_space(sdev); /* Replay domain mappings on the associated memory region */ g_tree_foreach(domain->mappings, virtio_iommu_notify_map_cb, @@ -887,6 +990,7 @@ static void virtio_iommu_set_config(VirtIODevice *vdev, return; } dev_config->bypass = in_config->bypass; + virtio_iommu_switch_address_space_all(dev); } trace_virtio_iommu_set_config(in_config->bypass); @@ -1026,6 +1130,8 @@ static void virtio_iommu_system_reset(void *opaque) * system reset */ s->config.bypass = s->boot_bypass; + virtio_iommu_switch_address_space_all(s); + } static void virtio_iommu_device_realize(DeviceState *dev, Error **errp) @@ -1041,6 +1147,11 @@ static void virtio_iommu_device_realize(DeviceState *dev, Error **errp) virtio_iommu_handle_command); s->event_vq = virtio_add_queue(vdev, VIOMMU_DEFAULT_QUEUE_SIZE, NULL); + /* + * config.bypass is needed to get initial address space early, such as + * in vfio realize + */ + s->config.bypass = s->boot_bypass; s->config.page_size_mask = TARGET_PAGE_MASK; s->config.input_range.end = UINT64_MAX; s->config.domain_range.end = UINT32_MAX; diff --git a/include/hw/virtio/virtio-iommu.h b/include/hw/virtio/virtio-iommu.h index 84391f8448..102eeefa73 100644 --- a/include/hw/virtio/virtio-iommu.h +++ b/include/hw/virtio/virtio-iommu.h @@ -37,6 +37,8 @@ typedef struct IOMMUDevice { int devfn; IOMMUMemoryRegion iommu_mr; AddressSpace as; + MemoryRegion root; /* The root container of the device */ + MemoryRegion bypass_mr; /* The alias of shared memory MR */ } IOMMUDevice; typedef struct IOMMUPciBus {