[Qemu-devel] Re: [PATCHv4 15/15] Pass boot device list to firmware.

["Michael S. Tsirkin" <mst@redhat.com>]

On Sun, Nov 14, 2010 at 08:52:37PM +0200, Gleb Natapov wrote:
> On Sun, Nov 14, 2010 at 08:41:37PM +0200, Michael S. Tsirkin wrote:
> > On Sun, Nov 14, 2010 at 05:39:41PM +0200, Gleb Natapov wrote:
> > > 
> > > Signed-off-by: Gleb Natapov <gleb@redhat.com>
> > > ---
> > >  hw/fw_cfg.c |   14 ++++++++++++++
> > >  hw/fw_cfg.h |    4 +++-
> > >  sysemu.h    |    1 +
> > >  vl.c        |   51 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  4 files changed, 69 insertions(+), 1 deletions(-)
> > > 
> > > diff --git a/hw/fw_cfg.c b/hw/fw_cfg.c
> > > index 7b9434f..f6a67db 100644
> > > --- a/hw/fw_cfg.c
> > > +++ b/hw/fw_cfg.c
> > > @@ -53,6 +53,7 @@ struct FWCfgState {
> > >      FWCfgFiles *files;
> > >      uint16_t cur_entry;
> > >      uint32_t cur_offset;
> > > +    Notifier machine_ready;
> > >  };
> > >  
> > >  static void fw_cfg_write(FWCfgState *s, uint8_t value)
> > > @@ -315,6 +316,15 @@ int fw_cfg_add_file(FWCfgState *s,  const char *filename, uint8_t *data,
> > >      return 1;
> > >  }
> > >  
> > > +static void fw_cfg_machine_ready(struct Notifier* n)
> > > +{
> > > +    uint32_t len;
> > > +    char *bootindex = get_boot_devices_list(&len);
> > > +
> > > +    fw_cfg_add_bytes(container_of(n, FWCfgState, machine_ready),
> > > +                     FW_CFG_BOOTINDEX, (uint8_t*)bootindex, len);
> > > +}
> > > +
> > >  FWCfgState *fw_cfg_init(uint32_t ctl_port, uint32_t data_port,
> > >                          target_phys_addr_t ctl_addr, target_phys_addr_t data_addr)
> > >  {
> > > @@ -343,6 +353,10 @@ FWCfgState *fw_cfg_init(uint32_t ctl_port, uint32_t data_port,
> > >      fw_cfg_add_i16(s, FW_CFG_MAX_CPUS, (uint16_t)max_cpus);
> > >      fw_cfg_add_i16(s, FW_CFG_BOOT_MENU, (uint16_t)boot_menu);
> > >  
> > > +
> > > +    s->machine_ready.notify = fw_cfg_machine_ready;
> > > +    qemu_add_machine_init_done_notifier(&s->machine_ready);
> > > +
> > >      return s;
> > >  }
> > >  
> > > diff --git a/hw/fw_cfg.h b/hw/fw_cfg.h
> > > index 856bf91..4d61410 100644
> > > --- a/hw/fw_cfg.h
> > > +++ b/hw/fw_cfg.h
> > > @@ -30,7 +30,9 @@
> > >  
> > >  #define FW_CFG_FILE_FIRST       0x20
> > >  #define FW_CFG_FILE_SLOTS       0x10
> > > -#define FW_CFG_MAX_ENTRY        (FW_CFG_FILE_FIRST+FW_CFG_FILE_SLOTS)
> > > +#define FW_CFG_FILE_LAST_SLOT   (FW_CFG_FILE_FIRST+FW_CFG_FILE_SLOTS)
> > > +#define FW_CFG_BOOTINDEX        (FW_CFG_FILE_LAST_SLOT + 1)
> > > +#define FW_CFG_MAX_ENTRY        FW_CFG_BOOTINDEX 
> > >  
> > >  #define FW_CFG_WRITE_CHANNEL    0x4000
> > >  #define FW_CFG_ARCH_LOCAL       0x8000
> > > diff --git a/sysemu.h b/sysemu.h
> > > index c42f33a..38a20a3 100644
> > > --- a/sysemu.h
> > > +++ b/sysemu.h
> > > @@ -196,4 +196,5 @@ void register_devices(void);
> > >  
> > >  void add_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >                            const char *suffix);
> > > +char *get_boot_devices_list(uint32_t *size);
> > >  #endif
> > > diff --git a/vl.c b/vl.c
> > > index 918d988..cca1e76 100644
> > > --- a/vl.c
> > > +++ b/vl.c
> > > @@ -735,6 +735,57 @@ void add_boot_device_path(int32_t bootindex, DeviceState *dev,
> > >      QTAILQ_INSERT_TAIL(&fw_boot_order, node, link);
> > >  }
> > >  
> > > +/*
> > > + * This function returns device list as an array in a below format:
> > > + * +-----+-----+---------------+-----+---------------+--
> > > + * |  n  |  l1 |   devpath1    |  l2 |  devpath2     | ...
> > > + * +-----+-----+---------------+-----+---------------+--
> > 
> > No one will ever want > 256 devices? Let's make it 4 byte or something.
> > 
> More then 256 _boot_ devices. I think this is more then reasonable.
> 
> > > + * where:
> > > + *   n - a number of devise pathes (one byte)
> > > + *   l - length of following device path string (one byte)
> > 
> > Might not fit: with pci we can have 256 nested buses.
> Theoretically. But will it practically happen?

Why not? It's easy to specify this on qemu command line.
You do nothing to detect this and gracefully fail either, do you?

-- 
MST