Creates and supports a GPA->IOVA tree and a partial IOVA->HVA tree by splitting up guest-backed memory maps and host-only memory maps from the full IOVA->HVA tree. That is, any guest-backed memory maps are now stored in the GPA->IOVA tree and host-only memory maps stay in the IOVA->HVA tree.
The qemu_ram_block_from_host() function in vhost_svq_translate_addr() is used to determine if the HVA (from the iovec) is backed by guest memory by attempting to infer a RAM block from it. If a valid RAMBlock is returned, we derive the GPA from it and search the GPA->IOVA tree for the corresponding IOVA. If an invalid RAMBlock is returned, the HVA is used to search the IOVA->HVA tree for the corresponding IOVA. This method of determining if an HVA is backed by guest memory is far from optimal, especially for memory buffers backed by host-only memory. In the next patch, this method will be improved by utilizing the in_addr and out_addr members of a VirtQueueElement to determine if an incoming address for translation is backed by guest or host-only memory. Signed-off-by: Jonah Palmer <jonah.pal...@oracle.com> --- hw/virtio/vhost-iova-tree.c | 67 ++++++++++++++++++++++++++++++ hw/virtio/vhost-iova-tree.h | 5 +++ hw/virtio/vhost-shadow-virtqueue.c | 28 ++++++++++--- hw/virtio/vhost-vdpa.c | 19 ++++----- include/qemu/iova-tree.h | 22 ++++++++++ util/iova-tree.c | 46 ++++++++++++++++++++ 6 files changed, 171 insertions(+), 16 deletions(-) diff --git a/hw/virtio/vhost-iova-tree.c b/hw/virtio/vhost-iova-tree.c index 216885aa3c..9d2d6a7af2 100644 --- a/hw/virtio/vhost-iova-tree.c +++ b/hw/virtio/vhost-iova-tree.c @@ -31,6 +31,9 @@ struct VhostIOVATree { /* Allocated IOVA addresses */ IOVATree *iova_map; + + /* GPA->IOVA address memory maps */ + IOVATree *gpa_iova_map; }; /** @@ -48,6 +51,7 @@ VhostIOVATree *vhost_iova_tree_new(hwaddr iova_first, hwaddr iova_last) tree->iova_taddr_map = iova_tree_new(); tree->iova_map = iova_tree_new(); + tree->gpa_iova_map = gpa_tree_new(); return tree; } @@ -58,6 +62,7 @@ void vhost_iova_tree_delete(VhostIOVATree *iova_tree) { iova_tree_destroy(iova_tree->iova_taddr_map); iova_tree_destroy(iova_tree->iova_map); + iova_tree_destroy(iova_tree->gpa_iova_map); g_free(iova_tree); } @@ -122,3 +127,65 @@ void vhost_iova_tree_remove(VhostIOVATree *iova_tree, DMAMap map) iova_tree_remove(iova_tree->iova_taddr_map, map); iova_tree_remove(iova_tree->iova_map, map); } + +/** + * Find the IOVA address stored from a guest memory address (GPA) + * + * @tree: The VhostIOVATree + * @map: The map with the guest memory address + * + * Returns the stored GPA->IOVA mapping, or NULL if not found. + */ +const DMAMap *vhost_iova_tree_find_gpa(const VhostIOVATree *tree, + const DMAMap *map) +{ + return iova_tree_find_iova(tree->gpa_iova_map, map); +} + +/** + * Allocate a new IOVA range and add the mapping to the GPA->IOVA tree + * + * @tree: The VhostIOVATree + * @map: The IOVA mapping + * @taddr: The translated address (GPA) + * + * Returns: + * - IOVA_OK if the map fits both containers + * - IOVA_ERR_INVALID if the map does not make sense (like size overflow) + * - IOVA_ERR_NOMEM if the IOVA-only tree cannot allocate more space + * + * It returns an assigned IOVA in map->iova if the return value is IOVA_OK. + */ +int vhost_iova_tree_map_alloc_gpa(VhostIOVATree *tree, DMAMap *map, hwaddr taddr) +{ + int ret; + + /* Some vhost devices don't like addr 0. Skip first page */ + hwaddr iova_first = tree->iova_first ?: qemu_real_host_page_size(); + + if (taddr + map->size < taddr || map->perm == IOMMU_NONE) { + return IOVA_ERR_INVALID; + } + + /* Allocate a node in the IOVA-only tree */ + ret = iova_tree_alloc_map(tree->iova_map, map, iova_first, tree->iova_last); + if (unlikely(ret != IOVA_OK)) { + return ret; + } + + /* Insert a node in the GPA->IOVA tree */ + map->translated_addr = taddr; + return gpa_tree_insert(tree->gpa_iova_map, map); +} + +/** + * Remove existing mappings from the IOVA-only and GPA->IOVA trees + * + * @tree: The VhostIOVATree + * @map: The map to remove + */ +void vhost_iova_tree_remove_gpa(VhostIOVATree *iova_tree, DMAMap map) +{ + iova_tree_remove(iova_tree->gpa_iova_map, map); + iova_tree_remove(iova_tree->iova_map, map); +} diff --git a/hw/virtio/vhost-iova-tree.h b/hw/virtio/vhost-iova-tree.h index 525ce72b1d..0c4ba5abd5 100644 --- a/hw/virtio/vhost-iova-tree.h +++ b/hw/virtio/vhost-iova-tree.h @@ -24,5 +24,10 @@ const DMAMap *vhost_iova_tree_find_iova(const VhostIOVATree *iova_tree, int vhost_iova_tree_map_alloc(VhostIOVATree *iova_tree, DMAMap *map, hwaddr taddr); void vhost_iova_tree_remove(VhostIOVATree *iova_tree, DMAMap map); +const DMAMap *vhost_iova_tree_find_gpa(const VhostIOVATree *iova_tree, + const DMAMap *map); +int vhost_iova_tree_map_alloc_gpa(VhostIOVATree *iova_tree, DMAMap *map, + hwaddr taddr); +void vhost_iova_tree_remove_gpa(VhostIOVATree *iova_tree, DMAMap map); #endif diff --git a/hw/virtio/vhost-shadow-virtqueue.c b/hw/virtio/vhost-shadow-virtqueue.c index 37aca8b431..a53492fd36 100644 --- a/hw/virtio/vhost-shadow-virtqueue.c +++ b/hw/virtio/vhost-shadow-virtqueue.c @@ -16,6 +16,7 @@ #include "qemu/log.h" #include "qemu/memalign.h" #include "linux-headers/linux/vhost.h" +#include "exec/ramblock.h" /** * Validate the transport device features that both guests can use with the SVQ @@ -88,14 +89,31 @@ static bool vhost_svq_translate_addr(const VhostShadowVirtqueue *svq, } for (size_t i = 0; i < num; ++i) { - DMAMap needle = { - .translated_addr = (hwaddr)(uintptr_t)iovec[i].iov_base, - .size = iovec[i].iov_len, - }; Int128 needle_last, map_last; size_t off; + RAMBlock *rb; + hwaddr gpa; + ram_addr_t offset; + const DMAMap *map; + DMAMap needle; + + rb = qemu_ram_block_from_host(iovec[i].iov_base, false, &offset); + if (rb) { + gpa = rb->offset + offset; + + needle = (DMAMap) { + .translated_addr = gpa, + .size = iovec[i].iov_len, + }; + map = vhost_iova_tree_find_gpa(svq->iova_tree, &needle); + } else { + needle = (DMAMap) { + .translated_addr = (hwaddr)(uintptr_t)iovec[i].iov_base, + .size = iovec[i].iov_len, + }; + map = vhost_iova_tree_find_iova(svq->iova_tree, &needle); + } - const DMAMap *map = vhost_iova_tree_find_iova(svq->iova_tree, &needle); /* * Map cannot be NULL since iova map contains all guest space and * qemu already has a physical address mapped diff --git a/hw/virtio/vhost-vdpa.c b/hw/virtio/vhost-vdpa.c index 703dcfc929..7efbde3d4c 100644 --- a/hw/virtio/vhost-vdpa.c +++ b/hw/virtio/vhost-vdpa.c @@ -360,17 +360,17 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, llsize = int128_sub(llend, int128_make64(iova)); if (s->shadow_data) { int r; - hwaddr hw_vaddr = (hwaddr)(uintptr_t)vaddr; + hwaddr gpa = section->offset_within_address_space; mem_region.size = int128_get64(llsize) - 1, mem_region.perm = IOMMU_ACCESS_FLAG(true, section->readonly), - r = vhost_iova_tree_map_alloc(s->iova_tree, &mem_region, hw_vaddr); + r = vhost_iova_tree_map_alloc_gpa(s->iova_tree, &mem_region, gpa); if (unlikely(r != IOVA_OK)) { error_report("Can't allocate a mapping (%d)", r); - if (mem_region.translated_addr == hw_vaddr) { - error_report("Insertion to IOVA->HVA tree failed"); + if (mem_region.translated_addr == gpa) { + error_report("Insertion to GPA->IOVA tree failed"); /* Remove the mapping from the IOVA-only tree */ goto fail_map; } @@ -392,7 +392,7 @@ static void vhost_vdpa_listener_region_add(MemoryListener *listener, fail_map: if (s->shadow_data) { - vhost_iova_tree_remove(s->iova_tree, mem_region); + vhost_iova_tree_remove_gpa(s->iova_tree, mem_region); } fail: @@ -446,21 +446,18 @@ static void vhost_vdpa_listener_region_del(MemoryListener *listener, if (s->shadow_data) { const DMAMap *result; - const void *vaddr = memory_region_get_ram_ptr(section->mr) + - section->offset_within_region + - (iova - section->offset_within_address_space); DMAMap mem_region = { - .translated_addr = (hwaddr)(uintptr_t)vaddr, + .translated_addr = section->offset_within_address_space, .size = int128_get64(llsize) - 1, }; - result = vhost_iova_tree_find_iova(s->iova_tree, &mem_region); + result = vhost_iova_tree_find_gpa(s->iova_tree, &mem_region); if (!result) { /* The memory listener map wasn't mapped */ return; } iova = result->iova; - vhost_iova_tree_remove(s->iova_tree, *result); + vhost_iova_tree_remove_gpa(s->iova_tree, *result); } vhost_vdpa_iotlb_batch_begin_once(s); /* diff --git a/include/qemu/iova-tree.h b/include/qemu/iova-tree.h index 44a45931d5..16d354a814 100644 --- a/include/qemu/iova-tree.h +++ b/include/qemu/iova-tree.h @@ -40,6 +40,28 @@ typedef struct DMAMap { } QEMU_PACKED DMAMap; typedef gboolean (*iova_tree_iterator)(DMAMap *map); +/** + * gpa_tree_new: + * + * Create a new GPA->IOVA tree. + * + * Returns: the tree point on success, or NULL otherwise. + */ +IOVATree *gpa_tree_new(void); + +/** + * gpa_tree_insert: + * + * @tree: The GPA->IOVA tree we're inserting the mapping to + * @map: The GPA->IOVA mapping to insert + * + * Inserts a GPA range to the GPA->IOVA tree. If there are overlapped + * ranges, IOVA_ERR_OVERLAP will be returned. + * + * Return: 0 if successful, < 0 otherwise. + */ +int gpa_tree_insert(IOVATree *tree, const DMAMap *map); + /** * iova_tree_new: * diff --git a/util/iova-tree.c b/util/iova-tree.c index 06295e2755..5b0c95ff15 100644 --- a/util/iova-tree.c +++ b/util/iova-tree.c @@ -257,3 +257,49 @@ void iova_tree_destroy(IOVATree *tree) g_tree_destroy(tree->tree); g_free(tree); } + +static int gpa_tree_compare(gconstpointer a, gconstpointer b, gpointer data) +{ + const DMAMap *m1 = a, *m2 = b; + + if (m1->translated_addr > m2->translated_addr + m2->size) { + return 1; + } + + if (m1->translated_addr + m1->size < m2->translated_addr) { + return -1; + } + + /* Overlapped */ + return 0; +} + +IOVATree *gpa_tree_new(void) +{ + IOVATree *gpa_tree = g_new0(IOVATree, 1); + + gpa_tree->tree = g_tree_new_full(gpa_tree_compare, NULL, g_free, NULL); + + return gpa_tree; +} + +int gpa_tree_insert(IOVATree *tree, const DMAMap *map) +{ + DMAMap *new; + + if (map->translated_addr + map->size < map->translated_addr || + map->perm == IOMMU_NONE) { + return IOVA_ERR_INVALID; + } + + /* We don't allow inserting ranges that overlap with existing ones */ + if (iova_tree_find(tree, map)) { + return IOVA_ERR_OVERLAP; + } + + new = g_new0(DMAMap, 1); + memcpy(new, map, sizeof(*new)); + iova_tree_insert_internal(tree->tree, new); + + return IOVA_OK; +} -- 2.43.5