* [PATCH 3/3] vhost_user: support for memory regions
2025-08-08 4:29 [PATCH 0/3] vhost_user: configure memory slots Pravin M Bathija
2025-08-08 4:29 ` [PATCH 1/3] mailmap: add user Pravin M Bathija
2025-08-08 4:29 ` [PATCH 2/3] vhost_user: configure memory slots Pravin M Bathija
@ 2025-08-08 4:29 ` Pravin M Bathija
2 siblings, 0 replies; 4+ messages in thread
From: Pravin M Bathija @ 2025-08-08 4:29 UTC (permalink / raw)
To: dev; +Cc: pravin.bathija, pravin.m.bathija.dev, boris.glimcher
From: Pravin M Bathija <pravin.m.bathija.dev@gmail.com>
- modify data structures and add functions to support
add and remove memory regions/slots
- define VHOST_MEMORY_MAX_NREGIONS & modify function
vhost_user_set_mem_table accordingly
- dynamically add new memory slots via vhost_user_add_mem_reg
- remove unused memory slots via vhost_user_rem_mem_reg
- define data structure VhostUserSingleMemReg for single
memory region
- modify data structures VhostUserRequest & VhostUserMsg
Signed-off-by: Pravin M Bathija <pravin.bathija@dell.com>
---
lib/vhost/vhost_user.c | 325 +++++++++++++++++++++++++++++++++++------
lib/vhost/vhost_user.h | 10 ++
2 files changed, 291 insertions(+), 44 deletions(-)
diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c
index b73dec6a22..dc72007584 100644
--- a/lib/vhost/vhost_user.c
+++ b/lib/vhost/vhost_user.c
@@ -74,6 +74,9 @@ VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, vhost_user_set_features, false, t
VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, true) \
VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, false) \
VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_GET_MAX_MEM_SLOTS, vhost_user_get_max_mem_slots, false, false) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_ADD_MEM_REG, vhost_user_add_mem_reg, true, true) \
+VHOST_MESSAGE_HANDLER(VHOST_USER_REM_MEM_REG, vhost_user_rem_mem_reg, true, true) \
VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, true, true) \
VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, true) \
VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, false, true) \
@@ -228,7 +231,17 @@ async_dma_map(struct virtio_net *dev, bool do_map)
}
static void
-free_mem_region(struct virtio_net *dev)
+free_mem_region(struct rte_vhost_mem_region *reg)
+{
+ if (reg != NULL && reg->host_user_addr) {
+ munmap(reg->mmap_addr, reg->mmap_size);
+ close(reg->fd);
+ memset(reg, 0, sizeof(struct rte_vhost_mem_region));
+ }
+}
+
+static void
+free_all_mem_regions(struct virtio_net *dev)
{
uint32_t i;
struct rte_vhost_mem_region *reg;
@@ -239,12 +252,10 @@ free_mem_region(struct virtio_net *dev)
if (dev->async_copy && rte_vfio_is_enabled("vfio"))
async_dma_map(dev, false);
- for (i = 0; i < dev->mem->nregions; i++) {
+ for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
reg = &dev->mem->regions[i];
- if (reg->host_user_addr) {
- munmap(reg->mmap_addr, reg->mmap_size);
- close(reg->fd);
- }
+ if (reg->mmap_addr)
+ free_mem_region(reg);
}
}
@@ -258,7 +269,7 @@ vhost_backend_cleanup(struct virtio_net *dev)
vdpa_dev->ops->dev_cleanup(dev->vid);
if (dev->mem) {
- free_mem_region(dev);
+ free_all_mem_regions(dev);
rte_free(dev->mem);
dev->mem = NULL;
}
@@ -707,7 +718,7 @@ numa_realloc(struct virtio_net **pdev, struct vhost_virtqueue **pvq)
vhost_devices[dev->vid] = dev;
mem_size = sizeof(struct rte_vhost_memory) +
- sizeof(struct rte_vhost_mem_region) * dev->mem->nregions;
+ sizeof(struct rte_vhost_mem_region) * VHOST_MEMORY_MAX_NREGIONS;
mem = rte_realloc_socket(dev->mem, mem_size, 0, node);
if (!mem) {
VHOST_CONFIG_LOG(dev->ifname, ERR,
@@ -811,8 +822,10 @@ hua_to_alignment(struct rte_vhost_memory *mem, void *ptr)
uint32_t i;
uintptr_t hua = (uintptr_t)ptr;
- for (i = 0; i < mem->nregions; i++) {
+ for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
r = &mem->regions[i];
+ if (r->host_user_addr == 0)
+ continue;
if (hua >= r->host_user_addr &&
hua < r->host_user_addr + r->size) {
return get_blk_size(r->fd);
@@ -1250,9 +1263,13 @@ vhost_user_postcopy_register(struct virtio_net *dev, int main_fd,
* retrieve the region offset when handling userfaults.
*/
memory = &ctx->msg.payload.memory;
- for (i = 0; i < memory->nregions; i++) {
+ for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+ int reg_msg_index = 0;
reg = &dev->mem->regions[i];
- memory->regions[i].userspace_addr = reg->host_user_addr;
+ if (reg->host_user_addr == 0)
+ continue;
+ memory->regions[reg_msg_index].userspace_addr = reg->host_user_addr;
+ reg_msg_index++;
}
/* Send the addresses back to qemu */
@@ -1279,8 +1296,10 @@ vhost_user_postcopy_register(struct virtio_net *dev, int main_fd,
}
/* Now userfault register and we can use the memory */
- for (i = 0; i < memory->nregions; i++) {
+ for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
reg = &dev->mem->regions[i];
+ if (reg->host_user_addr == 0)
+ continue;
if (vhost_user_postcopy_region_register(dev, reg) < 0)
return -1;
}
@@ -1385,6 +1404,46 @@ vhost_user_mmap_region(struct virtio_net *dev,
return 0;
}
+static int
+vhost_user_initialize_memory(struct virtio_net **pdev)
+{
+ struct virtio_net *dev = *pdev;
+ int numa_node = SOCKET_ID_ANY;
+
+ /*
+ * If VQ 0 has already been allocated, try to allocate on the same
+ * NUMA node. It can be reallocated later in numa_realloc().
+ */
+ if (dev->nr_vring > 0)
+ numa_node = dev->virtqueue[0]->numa_node;
+
+ dev->nr_guest_pages = 0;
+ if (dev->guest_pages == NULL) {
+ dev->max_guest_pages = 8;
+ dev->guest_pages = rte_zmalloc_socket(NULL,
+ dev->max_guest_pages *
+ sizeof(struct guest_page),
+ RTE_CACHE_LINE_SIZE,
+ numa_node);
+ if (dev->guest_pages == NULL) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "failed to allocate memory for dev->guest_pages");
+ return -1;
+ }
+ }
+
+ dev->mem = rte_zmalloc_socket("vhost-mem-table", sizeof(struct rte_vhost_memory) +
+ sizeof(struct rte_vhost_mem_region) * VHOST_MEMORY_MAX_NREGIONS, 0, numa_node);
+ if (dev->mem == NULL) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to allocate memory for dev->mem");
+ rte_free(dev->guest_pages);
+ dev->guest_pages = NULL;
+ return -1;
+ }
+
+ return 0;
+}
+
static int
vhost_user_set_mem_table(struct virtio_net **pdev,
struct vhu_msg_context *ctx,
@@ -1393,7 +1452,6 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
struct virtio_net *dev = *pdev;
struct VhostUserMemory *memory = &ctx->msg.payload.memory;
struct rte_vhost_mem_region *reg;
- int numa_node = SOCKET_ID_ANY;
uint64_t mmap_offset;
uint32_t i;
bool async_notify = false;
@@ -1438,39 +1496,13 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))
vhost_user_iotlb_flush_all(dev);
- free_mem_region(dev);
+ free_all_mem_regions(dev);
rte_free(dev->mem);
dev->mem = NULL;
}
- /*
- * If VQ 0 has already been allocated, try to allocate on the same
- * NUMA node. It can be reallocated later in numa_realloc().
- */
- if (dev->nr_vring > 0)
- numa_node = dev->virtqueue[0]->numa_node;
-
- dev->nr_guest_pages = 0;
- if (dev->guest_pages == NULL) {
- dev->max_guest_pages = 8;
- dev->guest_pages = rte_zmalloc_socket(NULL,
- dev->max_guest_pages *
- sizeof(struct guest_page),
- RTE_CACHE_LINE_SIZE,
- numa_node);
- if (dev->guest_pages == NULL) {
- VHOST_CONFIG_LOG(dev->ifname, ERR,
- "failed to allocate memory for dev->guest_pages");
- goto close_msg_fds;
- }
- }
-
- dev->mem = rte_zmalloc_socket("vhost-mem-table", sizeof(struct rte_vhost_memory) +
- sizeof(struct rte_vhost_mem_region) * memory->nregions, 0, numa_node);
- if (dev->mem == NULL) {
- VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to allocate memory for dev->mem");
- goto free_guest_pages;
- }
+ if (vhost_user_initialize_memory(pdev) < 0)
+ goto close_msg_fds;
for (i = 0; i < memory->nregions; i++) {
reg = &dev->mem->regions[i];
@@ -1534,11 +1566,182 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
return RTE_VHOST_MSG_RESULT_OK;
free_mem_table:
- free_mem_region(dev);
+ free_all_mem_regions(dev);
rte_free(dev->mem);
dev->mem = NULL;
+ rte_free(dev->guest_pages);
+ dev->guest_pages = NULL;
+close_msg_fds:
+ close_msg_fds(ctx);
+ return RTE_VHOST_MSG_RESULT_ERR;
+}
+
+
+static int
+vhost_user_get_max_mem_slots(struct virtio_net **pdev __rte_unused,
+ struct vhu_msg_context *ctx,
+ int main_fd __rte_unused)
+{
+ uint32_t max_mem_slots = VHOST_MEMORY_MAX_NREGIONS;
+
+ ctx->msg.payload.u64 = (uint64_t)max_mem_slots;
+ ctx->msg.size = sizeof(ctx->msg.payload.u64);
+ ctx->fd_num = 0;
-free_guest_pages:
+ return RTE_VHOST_MSG_RESULT_REPLY;
+}
+
+static int
+vhost_user_add_mem_reg(struct virtio_net **pdev,
+ struct vhu_msg_context *ctx,
+ int main_fd __rte_unused)
+{
+ struct virtio_net *dev = *pdev;
+ struct VhostUserMemoryRegion *region = &ctx->msg.payload.memory_single.region;
+ uint32_t i;
+
+ /* make sure new region will fit */
+ if (dev->mem != NULL && dev->mem->nregions >= VHOST_MEMORY_MAX_NREGIONS) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "too many memory regions already (%u)",
+ dev->mem->nregions);
+ goto close_msg_fds;
+ }
+
+ /* make sure supplied memory fd present */
+ if (ctx->fd_num != 1) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "fd count makes no sense (%u)",
+ ctx->fd_num);
+ goto close_msg_fds;
+ }
+
+ /* Make sure no overlap in guest virtual address space */
+ if (dev->mem != NULL && dev->mem->nregions > 0) {
+ for (uint32_t i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+ struct rte_vhost_mem_region *current_region = &dev->mem->regions[i];
+
+ if (current_region->mmap_size == 0)
+ continue;
+
+ uint64_t current_region_guest_start = current_region->guest_user_addr;
+ uint64_t current_region_guest_end = current_region_guest_start
+ + current_region->mmap_size - 1;
+ uint64_t proposed_region_guest_start = region->userspace_addr;
+ uint64_t proposed_region_guest_end = proposed_region_guest_start
+ + region->memory_size - 1;
+ bool overlap = false;
+
+ bool curent_region_guest_start_overlap =
+ current_region_guest_start >= proposed_region_guest_start
+ && current_region_guest_start <= proposed_region_guest_end;
+ bool curent_region_guest_end_overlap =
+ current_region_guest_end >= proposed_region_guest_start
+ && current_region_guest_end <= proposed_region_guest_end;
+ bool proposed_region_guest_start_overlap =
+ proposed_region_guest_start >= current_region_guest_start
+ && proposed_region_guest_start <= current_region_guest_end;
+ bool proposed_region_guest_end_overlap =
+ proposed_region_guest_end >= current_region_guest_start
+ && proposed_region_guest_end <= current_region_guest_end;
+
+ overlap = curent_region_guest_start_overlap
+ || curent_region_guest_end_overlap
+ || proposed_region_guest_start_overlap
+ || proposed_region_guest_end_overlap;
+
+ if (overlap) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "requested memory region overlaps with another region");
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "\tRequested region address:0x%" PRIx64,
+ region->userspace_addr);
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "\tRequested region size:0x%" PRIx64,
+ region->memory_size);
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "\tOverlapping region address:0x%" PRIx64,
+ current_region->guest_user_addr);
+ VHOST_CONFIG_LOG(dev->ifname, ERR,
+ "\tOverlapping region size:0x%" PRIx64,
+ current_region->mmap_size);
+ goto close_msg_fds;
+ }
+
+ }
+ }
+
+ /* convert first region add to normal memory table set */
+ if (dev->mem == NULL) {
+ if (vhost_user_initialize_memory(pdev) < 0)
+ goto close_msg_fds;
+ }
+
+ /* find a new region and set it like memory table set does */
+ struct rte_vhost_mem_region *reg = NULL;
+ uint64_t mmap_offset;
+
+ for (uint32_t i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+ if (dev->mem->regions[i].guest_user_addr == 0) {
+ reg = &dev->mem->regions[i];
+ break;
+ }
+ }
+ if (reg == NULL) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR, "no free memory region");
+ goto close_msg_fds;
+ }
+
+ reg->guest_phys_addr = region->guest_phys_addr;
+ reg->guest_user_addr = region->userspace_addr;
+ reg->size = region->memory_size;
+ reg->fd = ctx->fds[0];
+
+ mmap_offset = region->mmap_offset;
+
+ if (vhost_user_mmap_region(dev, reg, mmap_offset) < 0) {
+ VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to mmap region");
+ goto close_msg_fds;
+ }
+
+ dev->mem->nregions++;
+
+ if (dev->async_copy && rte_vfio_is_enabled("vfio"))
+ async_dma_map(dev, true);
+
+ if (vhost_user_postcopy_register(dev, main_fd, ctx) < 0)
+ goto free_mem_table;
+
+ for (i = 0; i < dev->nr_vring; i++) {
+ struct vhost_virtqueue *vq = dev->virtqueue[i];
+
+ if (!vq)
+ continue;
+
+ if (vq->desc || vq->avail || vq->used) {
+ /* vhost_user_lock_all_queue_pairs locked all qps */
+ VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_SET_MEM_TABLE);
+
+ /*
+ * If the memory table got updated, the ring addresses
+ * need to be translated again as virtual addresses have
+ * changed.
+ */
+ vring_invalidate(dev, vq);
+
+ translate_ring_addresses(&dev, &vq);
+ *pdev = dev;
+ }
+ }
+
+ dump_guest_pages(dev);
+
+ return RTE_VHOST_MSG_RESULT_OK;
+
+free_mem_table:
+ free_all_mem_regions(dev);
+ rte_free(dev->mem);
+ dev->mem = NULL;
rte_free(dev->guest_pages);
dev->guest_pages = NULL;
close_msg_fds:
@@ -1546,6 +1749,40 @@ vhost_user_set_mem_table(struct virtio_net **pdev,
return RTE_VHOST_MSG_RESULT_ERR;
}
+static int
+vhost_user_rem_mem_reg(struct virtio_net **pdev __rte_unused,
+ struct vhu_msg_context *ctx __rte_unused,
+ int main_fd __rte_unused)
+{
+ struct virtio_net *dev = *pdev;
+ struct VhostUserMemoryRegion *region = &ctx->msg.payload.memory_single.region;
+
+ if (dev->mem != NULL && dev->mem->nregions > 0) {
+ for (uint32_t i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
+ struct rte_vhost_mem_region *current_region = &dev->mem->regions[i];
+
+ if (current_region->guest_user_addr == 0)
+ continue;
+
+ /*
+ * According to the vhost-user specification:
+ * The memory region to be removed is identified by its guest address,
+ * user address and size. The mmap offset is ignored.
+ */
+ if (region->userspace_addr == current_region->guest_user_addr
+ && region->guest_phys_addr == current_region->guest_phys_addr
+ && region->memory_size == current_region->size) {
+ free_mem_region(current_region);
+ dev->mem->nregions--;
+ return RTE_VHOST_MSG_RESULT_OK;
+ }
+ }
+ }
+
+ VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to find region");
+ return RTE_VHOST_MSG_RESULT_ERR;
+}
+
static bool
vq_is_ready(struct virtio_net *dev, struct vhost_virtqueue *vq)
{
diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h
index ef486545ba..5a0e747b58 100644
--- a/lib/vhost/vhost_user.h
+++ b/lib/vhost/vhost_user.h
@@ -32,6 +32,7 @@
(1ULL << VHOST_USER_PROTOCOL_F_BACKEND_SEND_FD) | \
(1ULL << VHOST_USER_PROTOCOL_F_HOST_NOTIFIER) | \
(1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT) | \
+ (1ULL << VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS) | \
(1ULL << VHOST_USER_PROTOCOL_F_STATUS))
typedef enum VhostUserRequest {
@@ -67,6 +68,9 @@ typedef enum VhostUserRequest {
VHOST_USER_POSTCOPY_END = 30,
VHOST_USER_GET_INFLIGHT_FD = 31,
VHOST_USER_SET_INFLIGHT_FD = 32,
+ VHOST_USER_GET_MAX_MEM_SLOTS = 36,
+ VHOST_USER_ADD_MEM_REG = 37,
+ VHOST_USER_REM_MEM_REG = 38,
VHOST_USER_SET_STATUS = 39,
VHOST_USER_GET_STATUS = 40,
} VhostUserRequest;
@@ -91,6 +95,11 @@ typedef struct VhostUserMemory {
VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
} VhostUserMemory;
+typedef struct VhostUserSingleMemReg {
+ uint64_t padding;
+ VhostUserMemoryRegion region;
+} VhostUserSingleMemReg;
+
typedef struct VhostUserLog {
uint64_t mmap_size;
uint64_t mmap_offset;
@@ -186,6 +195,7 @@ typedef struct __rte_packed_begin VhostUserMsg {
struct vhost_vring_state state;
struct vhost_vring_addr addr;
VhostUserMemory memory;
+ VhostUserSingleMemReg memory_single;
VhostUserLog log;
struct vhost_iotlb_msg iotlb;
VhostUserCryptoSessionParam crypto_session;
--
2.43.0
^ permalink raw reply [flat|nested] 4+ messages in thread