On Mon, Feb 17, 2025 at 05:40:07PM +0100, Albert Esteve wrote: > 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 <[email protected]> > --- > hw/virtio/vhost-user.c | 43 +++++++++++++++++++++++++++++++ > include/hw/virtio/vhost-backend.h | 9 +++++++ > include/hw/virtio/vhost-user.h | 1 + > include/hw/virtio/virtio.h | 2 ++ > 4 files changed, 55 insertions(+) > > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c > index d88e6f8c3c..9cc148f726 100644 > --- a/hw/virtio/vhost-user.c > +++ b/hw/virtio/vhost-user.c > @@ -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[VIRTIO_MAX_SHMEM_REGIONS]; > +} 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 { > @@ -3146,6 +3154,40 @@ 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; > + } > + > + assert(msg.payload.shmem.nregions <= VIRTIO_MAX_SHMEM_REGIONS); > + *nregions = msg.payload.shmem.nregions; > + memcpy(memory_sizes, > + &msg.payload.shmem.memory_sizes, > + sizeof(uint64_t) * VHOST_MEMORY_BASELINE_NREGIONS);
Should this be VIRTIO_MAX_SHMEM_REGIONS instead of
VHOST_MEMORY_BASELINE_NREGIONS?
> + return 0;
> +}
> +
> const VhostOps user_ops = {
> .backend_type = VHOST_BACKEND_TYPE_USER,
> .vhost_backend_init = vhost_user_backend_init,
> @@ -3184,4 +3226,5 @@ 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,
> };
> diff --git a/include/hw/virtio/vhost-backend.h
> b/include/hw/virtio/vhost-backend.h
> index 70c2e8ffee..b40d82a111 100644
> --- a/include/hw/virtio/vhost-backend.h
> +++ b/include/hw/virtio/vhost-backend.h
> @@ -159,6 +159,14 @@ 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);
> +/*
> + * Max regions is VIRTIO_MAX_SHMEM_REGIONS, so that is the maximum
> + * number of memory_sizes that will be accepted. */
> +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 +222,7 @@ 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,
> diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h
> index 9a3f238b43..bacc7d184c 100644
> --- a/include/hw/virtio/vhost-user.h
> +++ b/include/hw/virtio/vhost-user.h
> @@ -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
> };
>
> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> index a778547c79..319e2f5b06 100644
> --- a/include/hw/virtio/virtio.h
> +++ b/include/hw/virtio/virtio.h
> @@ -81,6 +81,8 @@ typedef struct VirtQueueElement
>
> #define VIRTIO_NO_VECTOR 0xffff
>
> +#define VIRTIO_MAX_SHMEM_REGIONS 256
> +
> /* special index value used internally for config irqs */
> #define VIRTIO_CONFIG_IRQ_IDX -1
>
> --
> 2.48.1
>
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