Re: [Qemu-devel] [PATCH 1/6] Use IO port for qemu<->guest BIOS communication.

[Gleb Natapov <gleb@qumranet.com>]

On Sun, Aug 24, 2008 at 08:39:44PM +0300, Blue Swirl wrote:
> On 8/24/08, Gleb Natapov <gleb@qumranet.com> wrote:
> > Use PIO to get configuration info between qemu process and guest BIOS.
> 
> Could you make this a separate device, so that it could be used in
> other machines? There is nothing PC-specific.
The code is less then 50 lines. Is it worth to move it to a separate
file (two of them .c and .h) before there is a real need?

> 
> >  +static uint32_t bios_cfg_read(void *opaque, uint32_t addr)
> >  +{
> >  +    BIOSCfgEntry *e = &bios_params.entries[bios_params.entry];
> 
> You should use the opaque parameter and cast that to BIOSCfgState.
> 
> >  +    if (!e->data)
> >  +        return 0;
> >  +
> >  +    return e->data[bios_params.cur_offset++ % e->len];
> 
> Instead of using modular arithmetic, zero should be returned for invalid values.
> 
> >  +static void bios_cfg_write(void *opaque, uint32_t addr, uint32_t value)
> >  +{
> >  +    bios_params.entry = value % BIOS_CFG_MAX_ENTRY;
> 
> Same here, its important for downward compatibility.
> 
> >  +    bios_cfg_add_data(BIOS_CFG_SIGNATURE, "QEMU", 4);
> 
> I'd add:
> +    bios_cfg_add_data(BIOS_CFG_ID, 1, 4);
> 
Done.

--
			Gleb.