Re: [XEN PATCH 3/7] tools: add a late_init argument to xs_introduce_domain

[Julien Grall <julien@xxxxxxx>]

Hi,

On 08/01/2022 00:49, Stefano Stabellini wrote:
> From: Luca Miccio <lucmiccio@xxxxxxxxx>
>
> Add a late_init argument to xs_introduce_domain to handle dom0less
> guests whose xenstore interfaces are initialized after boot.
>
> This patch mechanically adds the new parameter; it doesn't change
> behaviors.
>
> Signed-off-by: Luca Miccio <lucmiccio@xxxxxxxxx>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> CC: wl@xxxxxxx
> CC: anthony.perard@xxxxxxxxxx
> CC: jgross@xxxxxxxx
> CC: marmarek@xxxxxxxxxxxxxxxxxxxxxx
> ---
>   tools/include/xenstore.h          | 3 ++-
>   tools/libs/light/libxl_dom.c      | 3 ++-
>   tools/libs/store/xs.c             | 8 ++++++--
>   tools/python/xen/lowlevel/xs/xs.c | 2 +-
>   4 files changed, 11 insertions(+), 5 deletions(-)
>
> diff --git a/tools/include/xenstore.h b/tools/include/xenstore.h
> index 2b3f69fb61..1a302b5ff9 100644
> --- a/tools/include/xenstore.h
> +++ b/tools/include/xenstore.h
> @@ -226,7 +226,8 @@ bool xs_transaction_end(struct xs_handle *h, 
> xs_transaction_t t,
>   bool xs_introduce_domain(struct xs_handle *h,
>                          unsigned int domid,
>                          unsigned long mfn,
> -                         unsigned int eventchn);
> +                        unsigned int eventchn,
> +                        bool late_init);
>   
>   /* Set the target of a domain
>    * This tells the store daemon that a domain is targetting another one, so
> diff --git a/tools/libs/light/libxl_dom.c b/tools/libs/light/libxl_dom.c
> index 2abaab439c..bacfdfa9df 100644
> --- a/tools/libs/light/libxl_dom.c
> +++ b/tools/libs/light/libxl_dom.c
> @@ -497,7 +497,8 @@ retry_transaction:
>       if (!xs_transaction_end(ctx->xsh, t, 0))
>           if (errno == EAGAIN)
>               goto retry_transaction;
> -    xs_introduce_domain(ctx->xsh, domid, state->store_mfn, state->store_port);
> +    xs_introduce_domain(ctx->xsh, domid, state->store_mfn, state->store_port,
> +                        false);
>       free(vm_path);
>       return 0;
>   }
> diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c
> index 7a9a8b1656..dd47d607fd 100644
> --- a/tools/libs/store/xs.c
> +++ b/tools/libs/store/xs.c
> @@ -1089,16 +1089,18 @@ bool xs_transaction_end(struct xs_handle *h, 
> xs_transaction_t t,
>    */
>   bool xs_introduce_domain(struct xs_handle *h,
>                          unsigned int domid, unsigned long mfn,
> -                        unsigned int eventchn)
> +                        unsigned int eventchn, bool late_init)
The interface of libstore is meant to be stable/versioned. So I don't 
think you can change xs_introduce_domain().
>   {
>         char domid_str[MAX_STRLEN(domid)];
>         char mfn_str[MAX_STRLEN(mfn)];
>         char eventchn_str[MAX_STRLEN(eventchn)];
> -       struct iovec iov[3];
> +       char late_init_str[MAX_STRLEN(late_init)];
> +       struct iovec iov[4];
>   
>   	snprintf(domid_str, sizeof(domid_str), "%u", domid);
>         snprintf(mfn_str, sizeof(mfn_str), "%lu", mfn);
>         snprintf(eventchn_str, sizeof(eventchn_str), "%u", eventchn);
> +       snprintf(late_init_str, sizeof(late_init_str), "%u", late_init);
>   
>   	iov[0].iov_base = domid_str;
>         iov[0].iov_len = strlen(domid_str) + 1;
> @@ -1106,6 +1108,8 @@ bool xs_introduce_domain(struct xs_handle *h,
>         iov[1].iov_len = strlen(mfn_str) + 1;
>         iov[2].iov_base = eventchn_str;
>         iov[2].iov_len = strlen(eventchn_str) + 1;
> +       iov[3].iov_base = late_init_str;
> +       iov[3].iov_len = strlen(late_init_str) + 1;
>   
>   	return xs_bool(xs_talkv(h, XBT_NULL, XS_INTRODUCE, iov,
>                                 ARRAY_SIZE(iov), NULL));
> diff --git a/tools/python/xen/lowlevel/xs/xs.c 
> b/tools/python/xen/lowlevel/xs/xs.c
> index 0dad7fa5f2..dc667fb231 100644
> --- a/tools/python/xen/lowlevel/xs/xs.c
> +++ b/tools/python/xen/lowlevel/xs/xs.c
> @@ -678,7 +678,7 @@ static PyObject *xspy_introduce_domain(XsHandle *self, 
> PyObject *args)
>           return NULL;
>   
>       Py_BEGIN_ALLOW_THREADS
> -    result = xs_introduce_domain(xh, dom, page, port);
> +    result = xs_introduce_domain(xh, dom, page, port, false);
>       Py_END_ALLOW_THREADS
>   
>       return none(result);
Cheers,

--
Julien Grall