Re: [PATCH 16/22] mini-os: setup xenbus interface parameters

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Juergen Gross, on Tue 23 Aug 2016 17:16:02 +0200, wrote:
> In order to support HVMlite we need to get the ring page and event
> channel from the hypervisor via hypercalls. Move the already existing
> get_xenbus() function from arm specific coding to xenbus/xenbus.c and
> provide a similar paravirtualized function.
> 
> Signed-off-by: Juergen Gross <jgross@suse.com>

Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>

> ---
>  arch/arm/setup.c | 16 +---------------
>  arch/x86/setup.c |  1 +
>  events.c         |  3 +--
>  include/xenbus.h |  3 +++
>  xenbus/xenbus.c  | 40 +++++++++++++++++++++++++++++++---------
>  5 files changed, 37 insertions(+), 26 deletions(-)
> 
> diff --git a/arch/arm/setup.c b/arch/arm/setup.c
> index a021616..72e025a 100644
> --- a/arch/arm/setup.c
> +++ b/arch/arm/setup.c
> @@ -25,20 +25,6 @@ extern char shared_info_page[PAGE_SIZE];
>  
>  void *device_tree;
>  
> -void get_xenbus(void)
> -{
> -    uint64_t value;
> -
> -    if (hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &value))
> -        BUG();
> -
> -    start_info.store_evtchn = (int)value;
> -
> -    if(hvm_get_parameter(HVM_PARAM_STORE_PFN, &value))
> -        BUG();
> -    start_info.store_mfn = (unsigned long)value;
> -}
> -
>  /*
>   * INITIAL C ENTRY POINT.
>   */
> @@ -72,7 +58,7 @@ void arch_init(void *dtb_pointer, uint32_t physical_offset)
>  
>      /* Fill in start_info */
>      get_console(NULL);
> -    get_xenbus();
> +    get_xenbus(NULL);
>  
>      gic_init();
>  
> diff --git a/arch/x86/setup.c b/arch/x86/setup.c
> index 0c1f2ec..6645784 100644
> --- a/arch/x86/setup.c
> +++ b/arch/x86/setup.c
> @@ -138,6 +138,7 @@ arch_init(void *par)
>  	/* WARN: don't do printk before here, it uses information from
>  	   shared_info. Use xprintk instead. */
>  	get_console(par);
> +	get_xenbus(par);
>  	si = par;
>  	memcpy(&start_info, si, sizeof(*si));
>  
> diff --git a/events.c b/events.c
> index 76ea617..e8ef8aa 100644
> --- a/events.c
> +++ b/events.c
> @@ -46,8 +46,7 @@ void unbind_all_ports(void)
>  
>      for ( i = 0; i < NR_EVS; i++ )
>      {
> -        if ( i == console_evtchn ||
> -             i == start_info.store_evtchn)
> +        if ( i == console_evtchn || i == xenbus_evtchn )
>              continue;
>  
>          if ( test_and_clear_bit(i, bound_ports) )
> diff --git a/include/xenbus.h b/include/xenbus.h
> index d3bb7af..5646a25 100644
> --- a/include/xenbus.h
> +++ b/include/xenbus.h
> @@ -29,6 +29,9 @@ struct xenbus_event {
>  };
>  typedef struct xenbus_event *xenbus_event_queue;
>  
> +extern uint32_t xenbus_evtchn;
> +
> +void get_xenbus(void *p);
>  char *xenbus_watch_path_token(xenbus_transaction_t xbt, const char *path, const char *token, xenbus_event_queue *events);
>  char *xenbus_unwatch_path_token(xenbus_transaction_t xbt, const char *path, const char *token);
>  extern struct wait_queue_head xenbus_watch_queue;
> diff --git a/xenbus/xenbus.c b/xenbus/xenbus.c
> index 0ab387a..636786c 100644
> --- a/xenbus/xenbus.c
> +++ b/xenbus/xenbus.c
> @@ -26,6 +26,7 @@
>  #include <mini-os/sched.h>
>  #include <mini-os/wait.h>
>  #include <xen/io/xs_wire.h>
> +#include <xen/hvm/params.h>
>  #include <mini-os/spinlock.h>
>  #include <mini-os/xmalloc.h>
>  
> @@ -62,6 +63,31 @@ struct xenbus_req_info
>  #define NR_REQS 32
>  static struct xenbus_req_info req_info[NR_REQS];
>  
> +uint32_t xenbus_evtchn;
> +
> +#ifdef CONFIG_PARAVIRT
> +void get_xenbus(void *p)
> +{
> +    start_info_t *si = p;
> +
> +    xenbus_evtchn = si->store_evtchn;
> +    xenstore_buf = mfn_to_virt(si->store_mfn);
> +}
> +#else
> +void get_xenbus(void *p)
> +{
> +    uint64_t v;
> +
> +    if ( hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v) )
> +        BUG();
> +    xenbus_evtchn = v;
> +
> +    if( hvm_get_parameter(HVM_PARAM_STORE_PFN, &v) )
> +        BUG();
> +    xenstore_buf = (struct xenstore_domain_interface *)map_frame_virt(v);
> +}
> +#endif
> +
>  static void memcpy_from_ring(const void *Ring,
>          void *Dest,
>          int off,
> @@ -269,7 +295,7 @@ static void xenbus_thread_func(void *ign)
>              }
>  
>              wmb();
> -            notify_remote_via_evtchn(start_info.store_evtchn);
> +            notify_remote_via_evtchn(xenbus_evtchn);
>          }
>      }
>  }
> @@ -335,15 +361,11 @@ void init_xenbus(void)
>  {
>      int err;
>      DEBUG("init_xenbus called.\n");
> -    xenstore_buf = mfn_to_virt(start_info.store_mfn);
>      create_thread("xenstore", xenbus_thread_func, NULL);
>      DEBUG("buf at %p.\n", xenstore_buf);
> -    err = bind_evtchn(start_info.store_evtchn,
> -		      xenbus_evtchn_handler,
> -              NULL);
> -    unmask_evtchn(start_info.store_evtchn);
> -    printk("xenbus initialised on irq %d mfn %#llx\n",
> -	   err, (unsigned long long) start_info.store_mfn);
> +    err = bind_evtchn(xenbus_evtchn, xenbus_evtchn_handler, NULL);
> +    unmask_evtchn(xenbus_evtchn);
> +    printk("xenbus initialised on irq %d\n", err);
>  }
>  
>  void fini_xenbus(void)
> @@ -425,7 +447,7 @@ static void xb_write(int type, int req_id, xenbus_transaction_t trans_id,
>      xenstore_buf->req_prod += len;
>  
>      /* Send evtchn to notify remote */
> -    notify_remote_via_evtchn(start_info.store_evtchn);
> +    notify_remote_via_evtchn(xenbus_evtchn);
>  }
>  
>  /* Send a mesasge to xenbus, in the same fashion as xb_write, and
> -- 
> 2.6.6
> 

-- 
Samuel
"...[Linux's] capacity to talk via any medium except smoke signals."
(By Dr. Greg Wettstein, Roger Maris Cancer Center)

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