Re: [Xen-devel] [PATCH 15/22] mini-os: setup console interface parameters

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Juergen Gross, on Tue 23 Aug 2016 17:16:01 +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_console() function from arm specific coding to
> console/xencons_ring.c and provide a similar paravirtualized function.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Reviewed-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>

> ---
>  arch/arm/setup.c       | 16 +---------------
>  arch/x86/setup.c       |  1 +
>  console/xencons_ring.c | 38 ++++++++++++++++++++++++++++++--------
>  events.c               |  2 +-
>  include/console.h      |  3 ++-
>  5 files changed, 35 insertions(+), 25 deletions(-)
> 
> diff --git a/arch/arm/setup.c b/arch/arm/setup.c
> index cbe67c6..a021616 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;
>  
> -static void get_console(void)
> -{
> -    uint64_t v = -1;
> -
> -    hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
> -    start_info.console.domU.evtchn = v;
> -
> -    hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
> -    start_info.console.domU.mfn = v;
> -
> -    printk("Console is on port %d\n", start_info.console.domU.evtchn);
> -    printk("Console ring is at mfn %lx\n", (unsigned long) 
> start_info.console.domU.mfn);
> -}
> -
>  void get_xenbus(void)
>  {
>      uint64_t value;
> @@ -85,7 +71,7 @@ void arch_init(void *dtb_pointer, uint32_t physical_offset)
>      HYPERVISOR_shared_info = (struct shared_info *)shared_info_page;
>  
>      /* Fill in start_info */
> -    get_console();
> +    get_console(NULL);
>      get_xenbus();
>  
>      gic_init();
> diff --git a/arch/x86/setup.c b/arch/x86/setup.c
> index 8b6bb6e..0c1f2ec 100644
> --- a/arch/x86/setup.c
> +++ b/arch/x86/setup.c
> @@ -137,6 +137,7 @@ arch_init(void *par)
>       /* Copy the start_info struct to a globally-accessible area. */
>       /* WARN: don't do printk before here, it uses information from
>          shared_info. Use xprintk instead. */
> +     get_console(par);
>       si = par;
>       memcpy(&start_info, si, sizeof(*si));
>  
> diff --git a/console/xencons_ring.c b/console/xencons_ring.c
> index 81c8e99..dd64a41 100644
> --- a/console/xencons_ring.c
> +++ b/console/xencons_ring.c
> @@ -9,27 +9,49 @@
>  #include <xen/io/console.h>
>  #include <xen/io/protocols.h>
>  #include <xen/io/ring.h>
> +#include <xen/hvm/params.h>
>  #include <mini-os/xmalloc.h>
>  #include <mini-os/gnttab.h>
>  #include "console.h"
>  
>  DECLARE_WAIT_QUEUE_HEAD(console_queue);
>  
> +static struct xencons_interface *console_ring;
> +uint32_t console_evtchn;
> +
> +#ifdef CONFIG_PARAVIRT
> +void get_console(void *p)
> +{
> +    start_info_t *si = p;
> +
> +    console_ring = mfn_to_virt(si->console.domU.mfn);
> +    console_evtchn = si->console.domU.evtchn;
> +}
> +#else
> +void get_console(void *p)
> +{
> +    uint64_t v = -1;
> +
> +    hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
> +    console_evtchn = v;
> +
> +    hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
> +    console_ring = (struct xencons_interface *)map_frame_virt(v);
> +}
> +#endif
> +
>  static inline void notify_daemon(struct consfront_dev *dev)
>  {
>      /* Use evtchn: this is called early, before irq is set up. */
>      if (!dev)
> -        notify_remote_via_evtchn(start_info.console.domU.evtchn);
> +        notify_remote_via_evtchn(console_evtchn);
>      else
>          notify_remote_via_evtchn(dev->evtchn);
>  }
>  
>  static inline struct xencons_interface *xencons_interface(void)
>  {
> -    if (start_info.console.domU.evtchn)
> -        return mfn_to_virt(start_info.console.domU.mfn);
> -    else
> -        return NULL;
> +    return console_evtchn ? console_ring : NULL;
>  } 
>   
>  int xencons_ring_send_no_notify(struct consfront_dev *dev, const char *data, 
> unsigned len)
> @@ -158,7 +180,7 @@ struct consfront_dev *xencons_ring_init(void)
>       int err;
>       struct consfront_dev *dev;
>  
> -     if (!start_info.console.domU.evtchn)
> +     if (!console_evtchn)
>               return 0;
>  
>       dev = malloc(sizeof(struct consfront_dev));
> @@ -171,8 +193,8 @@ struct consfront_dev *xencons_ring_init(void)
>  #ifdef HAVE_LIBC
>       dev->fd = -1;
>  #endif
> -     dev->evtchn = start_info.console.domU.evtchn;
> -     dev->ring = (struct xencons_interface *) 
> mfn_to_virt(start_info.console.domU.mfn);
> +     dev->evtchn = console_evtchn;
> +     dev->ring = xencons_interface();
>  
>       err = bind_evtchn(dev->evtchn, console_handle_input, dev);
>       if (err <= 0) {
> diff --git a/events.c b/events.c
> index 2a23042..76ea617 100644
> --- a/events.c
> +++ b/events.c
> @@ -46,7 +46,7 @@ void unbind_all_ports(void)
>  
>      for ( i = 0; i < NR_EVS; i++ )
>      {
> -        if ( i == start_info.console.domU.evtchn ||
> +        if ( i == console_evtchn ||
>               i == start_info.store_evtchn)
>              continue;
>  
> diff --git a/include/console.h b/include/console.h
> index a77f47f..eb327a8 100644
> --- a/include/console.h
> +++ b/include/console.h
> @@ -61,7 +61,7 @@ struct consfront_dev {
>  #endif
>  };
>  
> -
> +extern uint32_t console_evtchn;
>  
>  void print(int direct, const char *fmt, va_list args);
>  void printk(const char *fmt, ...) __attribute__ ((format (printf, 1, 2)));
> @@ -72,6 +72,7 @@ void xprintk(const char *fmt, ...) __attribute__ ((format 
> (printf, 1, 2)));
>  void xencons_rx(char *buf, unsigned len, struct pt_regs *regs);
>  void xencons_tx(void);
>  
> +void get_console(void *p);
>  void init_console(void);
>  void console_print(struct consfront_dev *dev, char *data, int length);
>  void fini_console(struct consfront_dev *dev);
> -- 
> 2.6.6
> 

-- 
Samuel
        /* Amuse the user. */
        printk(
"              \\|/ ____ \\|/\n"
"              \"@'/ ,. \\`@\"\n"
"              /_| \\__/ |_\\\n"
"                 \\__U_/\n");
(From linux/arch/sparc/kernel/traps.c:die_if_kernel())

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