* Dr. David Alan Gilbert (git) ([email protected]) wrote:
> From: "Dr. David Alan Gilbert" <[email protected]>
>
> Add virtio-fs definitions to libvhost-user
>
> Signed-off-by: Dr. David Alan Gilbert <[email protected]>
> Reviewed-by: Stefan Hajnoczi <[email protected]>
I'm going to need to rework this
> +/* Structures carried over the slave channel back to QEMU */
> +#define VHOST_USER_FS_SLAVE_MAX_ENTRIES 32
> +
> +/* For the flags field of VhostUserFSSlaveMsg */
> +#define VHOST_USER_FS_FLAG_MAP_R (1u << 0)
> +#define VHOST_USER_FS_FLAG_MAP_W (1u << 1)
> +
> +typedef struct {
> + /* Offsets within the file being mapped */
> + uint64_t fd_offset;
> + /* Offsets within the cache */
> + uint64_t c_offset;
> + /* Lengths of sections */
> + uint64_t len;
> + /* Flags, from VHOST_USER_FS_FLAG_* */
> + uint64_t flags;
> +} VhostUserFSSlaveMsgEntry;
> +
> +typedef struct {
> + /* Number of entries */
> + uint16_t count;
> + /* Spare */
> + uint16_t align;
> +
> + VhostUserFSSlaveMsgEntry entries[];
> +} VhostUserFSSlaveMsg;
> +
> typedef struct VhostUserMemoryRegion {
> uint64_t guest_phys_addr;
> uint64_t memory_size;
> @@ -197,6 +224,7 @@ typedef struct VhostUserMsg {
> VhostUserConfig config;
> VhostUserVringArea area;
> VhostUserInflight inflight;
> + VhostUserFSSlaveMsg fs;
> } payload;
>
> int fds[VHOST_MEMORY_BASELINE_NREGIONS];
This fails Clang's build; because 'fs' is part of a union and
given it's entries[] is a variable length type, and is not
at the end of the union. It's got a good point - I really don't know
how gcc copes here; but also, what are vhost-user's rules
on the length of 'payload' - it looks like me putting
a larger message in there will break other demons.
I'd changed it from a fixed size array to variable size based
on Chirantan's comments on v1; but now I'm not even convinced
the fixed size was right, given that I'm not convinced I'm
allowed to change the length of payload.
Dave
> @@ -693,4 +721,16 @@ void vu_queue_get_avail_bytes(VuDev *vdev, VuVirtq *vq,
> unsigned int *in_bytes,
> bool vu_queue_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int in_bytes,
> unsigned int out_bytes);
>
> +/**
> + * vu_fs_cache_request: Send a slave message for an fs client
> + * @dev: a VuDev context
> + * @req: The request type (map, unmap, sync)
> + * @fd: an fd (only required for map, else must be -1)
> + * @fsm: The body of the message
> + *
> + * Returns: 0 or above for success, nevative errno on error
> + */
> +int64_t vu_fs_cache_request(VuDev *dev, VhostUserSlaveRequest req, int fd,
> + VhostUserFSSlaveMsg *fsm);
> +
> #endif /* LIBVHOST_USER_H */
> --
> 2.31.1
>
>
--
Dr. David Alan Gilbert / [email protected] / Manchester, UK
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