Re: [Qemu-devel] [PATCH v4 20/29] postcopy: postcopy_notify_shared_wake

[Marc-André Lureau]

On Thu, Mar 8, 2018 at 8:58 PM, Dr. David Alan Gilbert (git)
<address@hidden> wrote:
> From: "Dr. David Alan Gilbert" <address@hidden>
>
> Add a hook to allow a client userfaultfd to be 'woken'
> when a page arrives, and a walker that calls that
> hook for relevant clients given a RAMBlock and offset.
>
> Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> Reviewed-by: Peter Xu <address@hidden>

Reviewed-by: Marc-André Lureau <address@hidden>


> ---
>  migration/postcopy-ram.c | 16 ++++++++++++++++
>  migration/postcopy-ram.h | 10 ++++++++++
>  2 files changed, 26 insertions(+)
>
> diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c
> index d3e7f10c5a..585db9467a 100644
> --- a/migration/postcopy-ram.c
> +++ b/migration/postcopy-ram.c
> @@ -827,6 +827,22 @@ static int qemu_ufd_copy_ioctl(int userfault_fd, void 
> *host_addr,
>      return ret;
>  }
>
> +int postcopy_notify_shared_wake(RAMBlock *rb, uint64_t offset)
> +{
> +    int i;
> +    MigrationIncomingState *mis = migration_incoming_get_current();
> +    GArray *pcrfds = mis->postcopy_remote_fds;
> +
> +    for (i = 0; i < pcrfds->len; i++) {
> +        struct PostCopyFD *cur = &g_array_index(pcrfds, struct PostCopyFD, 
> i);
> +        int ret = cur->waker(cur, rb, offset);
> +        if (ret) {
> +            return ret;
> +        }
> +    }
> +    return 0;
> +}
> +
>  /*
>   * Place a host page (from) at (host) atomically
>   * returns 0 on success
> diff --git a/migration/postcopy-ram.h b/migration/postcopy-ram.h
> index f02fa36127..fef7448e4b 100644
> --- a/migration/postcopy-ram.h
> +++ b/migration/postcopy-ram.h
> @@ -148,6 +148,10 @@ struct PostCopyFD;
>
>  /* ufd is a pointer to the struct uffd_msg *TODO: more Portable! */
>  typedef int (*pcfdhandler)(struct PostCopyFD *pcfd, void *ufd);
> +/* Notification to wake, either on place or on reception of
> + * a fault on something that's already arrived (race)
> + */
> +typedef int (*pcfdwake)(struct PostCopyFD *pcfd, RAMBlock *rb, uint64_t 
> offset);
>
>  struct PostCopyFD {
>      int fd;
> @@ -155,6 +159,8 @@ struct PostCopyFD {
>      void *data;
>      /* Handler to be called whenever we get a poll event */
>      pcfdhandler handler;
> +    /* Notification to wake shared client */
> +    pcfdwake waker;
>      /* A string to use in error messages */
>      const char *idstr;
>  };
> @@ -164,6 +170,10 @@ struct PostCopyFD {
>   */
>  void postcopy_register_shared_ufd(struct PostCopyFD *pcfd);
>  void postcopy_unregister_shared_ufd(struct PostCopyFD *pcfd);
> +/* Call each of the shared 'waker's registerd telling them of
> + * availability of a block.
> + */
> +int postcopy_notify_shared_wake(RAMBlock *rb, uint64_t offset);
>  /* Notify a client ufd that a page is available
>   * Note: The 'client_address' is in the address space of the client
>   * program not QEMU
> --
> 2.14.3
>
>



-- 
Marc-André Lureau