@@ -348,6 +348,19 @@ Device state transfer parameters
In the future, additional phases might be added e.g. to allow
iterative migration while the device is running.
+VIRTIO Shared Memory Region configuration
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
++-------------+---------+------------+----+------------+
+| num regions | padding | mem size 0 | .. | mem size 7 |
++-------------+---------+------------+----+------------+
+
+:num regions: a 32-bit number of regions
+
+:padding: 32-bit
+
+:mem size: 64-bit size of VIRTIO Shared Memory Region
+
C structure
-----------
@@ -369,6 +382,10 @@ In QEMU the vhost-user message is implemented with the following struct:
VhostUserConfig config;
VhostUserVringArea area;
VhostUserInflight inflight;
+ VhostUserShared object;
+ VhostUserTransferDeviceState transfer_state;
+ VhostUserMMap mmap;
+ VhostUserShMemConfig shmem;
};
} QEMU_PACKED VhostUserMsg;
@@ -1051,6 +1068,7 @@ Protocol features
#define VHOST_USER_PROTOCOL_F_XEN_MMAP 17
#define VHOST_USER_PROTOCOL_F_SHARED_OBJECT 18
#define VHOST_USER_PROTOCOL_F_DEVICE_STATE 19
+ #define VHOST_USER_PROTOCOL_F_SHMEM 20
Front-end message types
-----------------------
@@ -1725,6 +1743,19 @@ Front-end message types
Using this function requires prior negotiation of the
``VHOST_USER_PROTOCOL_F_DEVICE_STATE`` feature.
+``VHOST_USER_GET_SHMEM_CONFIG``
+ :id: 44
+ :equivalent ioctl: N/A
+ :request payload: N/A
+ :reply payload: ``struct VhostUserShMemConfig``
+
+ When the ``VHOST_USER_PROTOCOL_F_SHMEM`` protocol feature has been
+ successfully negotiated, this message can be submitted by the front-end
+ to gather the VIRTIO Shared Memory Region configuration. Back-end will respond
+ with the number of VIRTIO Shared Memory Regions it requires, and each shared memory
+ region size in an array. The shared memory IDs are represented by the index
+ of the array.
+
Back-end message types
----------------------
@@ -104,6 +104,7 @@ typedef enum VhostUserRequest {
VHOST_USER_GET_SHARED_OBJECT = 41,
VHOST_USER_SET_DEVICE_STATE_FD = 42,
VHOST_USER_CHECK_DEVICE_STATE = 43,
+ VHOST_USER_GET_SHMEM_CONFIG = 44,
VHOST_USER_MAX
} VhostUserRequest;
@@ -138,6 +139,12 @@ typedef struct VhostUserMemRegMsg {
VhostUserMemoryRegion region;
} VhostUserMemRegMsg;
+typedef struct VhostUserShMemConfig {
+ uint32_t nregions;
+ uint32_t padding;
+ uint64_t memory_sizes[VHOST_MEMORY_BASELINE_NREGIONS];
+} VhostUserShMemConfig;
+
typedef struct VhostUserLog {
uint64_t mmap_size;
uint64_t mmap_offset;
@@ -245,6 +252,7 @@ typedef union {
VhostUserShared object;
VhostUserTransferDeviceState transfer_state;
VhostUserMMap mmap;
+ VhostUserShMemConfig shmem;
} VhostUserPayload;
typedef struct VhostUserMsg {
@@ -3136,6 +3144,39 @@ static int vhost_user_check_device_state(struct vhost_dev *dev, Error **errp)
return 0;
}
+static int vhost_user_get_shmem_config(struct vhost_dev *dev,
+ int *nregions,
+ uint64_t *memory_sizes,
+ Error **errp)
+{
+ int ret;
+ VhostUserMsg msg = {
+ .hdr.request = VHOST_USER_GET_SHMEM_CONFIG,
+ .hdr.flags = VHOST_USER_VERSION,
+ };
+
+ if (!virtio_has_feature(dev->protocol_features,
+ VHOST_USER_PROTOCOL_F_SHMEM)) {
+ return 0;
+ }
+
+ ret = vhost_user_write(dev, &msg, NULL, 0);
+ if (ret < 0) {
+ return ret;
+ }
+
+ ret = vhost_user_read(dev, &msg);
+ if (ret < 0) {
+ return ret;
+ }
+
+ *nregions = msg.payload.shmem.nregions;
+ memcpy(memory_sizes,
+ &msg.payload.shmem.memory_sizes,
+ sizeof(uint64_t) * VHOST_MEMORY_BASELINE_NREGIONS);
+ return 0;
+}
+
const VhostOps user_ops = {
.backend_type = VHOST_BACKEND_TYPE_USER,
.vhost_backend_init = vhost_user_backend_init,
@@ -3174,4 +3215,5 @@ const VhostOps user_ops = {
.vhost_supports_device_state = vhost_user_supports_device_state,
.vhost_set_device_state_fd = vhost_user_set_device_state_fd,
.vhost_check_device_state = vhost_user_check_device_state,
+ .vhost_get_shmem_config = vhost_user_get_shmem_config,
};
@@ -159,6 +159,11 @@ typedef int (*vhost_set_device_state_fd_op)(struct vhost_dev *dev,
int *reply_fd,
Error **errp);
typedef int (*vhost_check_device_state_op)(struct vhost_dev *dev, Error **errp);
+typedef int (*vhost_get_shmem_config_op)(struct vhost_dev *dev,
+ int *nregions,
+ uint64_t *memory_sizes,
+ Error **errp);
+
typedef struct VhostOps {
VhostBackendType backend_type;
@@ -214,6 +219,7 @@ typedef struct VhostOps {
vhost_supports_device_state_op vhost_supports_device_state;
vhost_set_device_state_fd_op vhost_set_device_state_fd;
vhost_check_device_state_op vhost_check_device_state;
+ vhost_get_shmem_config_op vhost_get_shmem_config;
} VhostOps;
int vhost_backend_update_device_iotlb(struct vhost_dev *dev,
@@ -32,6 +32,7 @@ enum VhostUserProtocolFeature {
/* Feature 17 reserved for VHOST_USER_PROTOCOL_F_XEN_MMAP. */
VHOST_USER_PROTOCOL_F_SHARED_OBJECT = 18,
VHOST_USER_PROTOCOL_F_DEVICE_STATE = 19,
+ VHOST_USER_PROTOCOL_F_SHMEM = 20,
VHOST_USER_PROTOCOL_F_MAX
};
The frontend can use this command to retrieve VIRTIO Shared Memory Regions configuration from the backend. The response contains the number of shared memory regions, their size, and shmid. This is useful when the frontend is unaware of specific backend type and configuration, for example, in the `vhost-user-device` case. Signed-off-by: Albert Esteve <aesteve@redhat.com> --- docs/interop/vhost-user.rst | 31 +++++++++++++++++++++++ hw/virtio/vhost-user.c | 42 +++++++++++++++++++++++++++++++ include/hw/virtio/vhost-backend.h | 6 +++++ include/hw/virtio/vhost-user.h | 1 + 4 files changed, 80 insertions(+)