[v2,12/12] hw/isa/vt82c686: Implement relocation and toggling of SuperI/O functions

The VIA south bridges are able to relocate and toggle (enable or disable) their
SuperI/O functions. So far this is hardcoded such that all functions are always
enabled and are located at fixed addresses.

Some PC BIOSes seem to probe for I/O occupancy before activating such a function
and issue an error in case of a conflict. Since the functions are enabled on
reset, conflicts are always detected. Prevent that by implementing relocation
and toggling of the SuperI/O functions.

Note that all SuperI/O functions are now deactivated upon reset (except for
VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
no -bios is given -- to configure the functions accordingly.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
 1 file changed, 90 insertions(+), 31 deletions(-)

On Mon, 18 Dec 2023, Bernhard Beschow wrote:
> The VIA south bridges are able to relocate and toggle (enable or disable) their
> SuperI/O functions. So far this is hardcoded such that all functions are always
> enabled and are located at fixed addresses.
>
> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
> and issue an error in case of a conflict. Since the functions are enabled on
> reset, conflicts are always detected. Prevent that by implementing relocation
> and toggling of the SuperI/O functions.
>
> Note that all SuperI/O functions are now deactivated upon reset (except for
> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
> no -bios is given -- to configure the functions accordingly.

Pegasos2 emulates firmware when no -bios is given, this was explained in 
previos commit so maybe not needed to be explained it here again so you 
could drop the comment between -- -- but I don't mind.

> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
> ---
> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
> 1 file changed, 90 insertions(+), 31 deletions(-)
>
> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
> index 9c2333a277..be202d23cf 100644
> --- a/hw/isa/vt82c686.c
> +++ b/hw/isa/vt82c686.c
> @@ -15,6 +15,9 @@
>
> #include "qemu/osdep.h"
> #include "hw/isa/vt82c686.h"
> +#include "hw/block/fdc.h"
> +#include "hw/char/parallel-isa.h"
> +#include "hw/char/serial.h"
> #include "hw/pci/pci.h"
> #include "hw/qdev-properties.h"
> #include "hw/ide/pci.h"
> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>
> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>
> +static void vt82c686b_superio_update(ViaSuperIOState *s)
> +{
> +    isa_parallel_set_enabled(s->superio.parallel[0],
> +                             (s->regs[0xe2] & 0x3) != 3);
> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
> +
> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
> +}

I wonder if some code duplication could be saved by adding a shared 
via_superio_update() for this further up in the abstract via-superio class 
instead of this method and vt8231_superio_update() below. This common 
method in abstract class would need to handle the differences which seem 
to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. 
These could either be handled by adding function parameters or fields to 
ViaSuperIOState for this that the subclasses can set and the method check. 
(Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or 
similar for how many ports are there then can have a for loop for those 
that would only run once for vt8231).

> +static int vmstate_vt82c686b_superio_post_load(void *opaque, int version_id)
> +{
> +    ViaSuperIOState *s = opaque;
> +
> +    vt82c686b_superio_update(s);
> +
> +    return 0;

You could lose some blank lines here. You seem to love them, half of your 
cover letter is just blank lines :-) but I'm the opposite and like more 
code to fit in one screen even on todays displays that are wider than 
tall. So this funciton would take less space without blank lines. (Even 
the local variable may not be necessary as you don't access any fields 
within and void * should just cast without a warning but for spelling out 
the desired type as a reminder I'm ok with leaving that but no excessive 
blank lines please if you don't mind that much.)

Regards,
BALATON Zoltan

> +}
> +
> +static const VMStateDescription vmstate_vt82c686b_superio = {
> +    .name = "vt82c686b_superio",
> +    .version_id = 1,
> +    .post_load = vmstate_vt82c686b_superio_post_load,
> +};
> +
> static void vt82c686b_superio_cfg_write(void *opaque, hwaddr addr,
>                                         uint64_t data, unsigned size)
> {
> @@ -368,7 +400,11 @@ static void vt82c686b_superio_cfg_write(void *opaque, hwaddr addr,
>     case 0xfd ... 0xff:
>         /* ignore write to read only registers */
>         return;
> -    /* case 0xe6 ... 0xe8: Should set base port of parallel and serial */
> +    case 0xe2 ... 0xe3:
> +    case 0xe6 ... 0xe8:
> +        sc->regs[idx] = data;
> +        vt82c686b_superio_update(sc);
> +        return;
>     default:
>         qemu_log_mask(LOG_UNIMP,
>                       "via_superio_cfg: unimplemented register 0x%x\n", idx);
> @@ -393,25 +429,24 @@ static void vt82c686b_superio_reset(DeviceState *dev)
>
>     memset(s->regs, 0, sizeof(s->regs));
>     /* Device ID */
> -    vt82c686b_superio_cfg_write(s, 0, 0xe0, 1);
> -    vt82c686b_superio_cfg_write(s, 1, 0x3c, 1);
> -    /* Function select - all disabled */
> -    vt82c686b_superio_cfg_write(s, 0, 0xe2, 1);
> -    vt82c686b_superio_cfg_write(s, 1, 0x03, 1);
> +    s->regs[0xe0] = 0x3c;
> +    /*
> +     * Function select - only serial enabled
> +     * Fuloong 2e's rescue-yl prints to the serial console w/o enabling it. This
> +     * suggests that the serial ports are enabled by default, so override the
> +     * datasheet.
> +     */
> +    s->regs[0xe2] = 0x0f;
>     /* Floppy ctrl base addr 0x3f0-7 */
> -    vt82c686b_superio_cfg_write(s, 0, 0xe3, 1);
> -    vt82c686b_superio_cfg_write(s, 1, 0xfc, 1);
> +    s->regs[0xe3] = 0xfc;
>     /* Parallel port base addr 0x378-f */
> -    vt82c686b_superio_cfg_write(s, 0, 0xe6, 1);
> -    vt82c686b_superio_cfg_write(s, 1, 0xde, 1);
> +    s->regs[0xe6] = 0xde;
>     /* Serial port 1 base addr 0x3f8-f */
> -    vt82c686b_superio_cfg_write(s, 0, 0xe7, 1);
> -    vt82c686b_superio_cfg_write(s, 1, 0xfe, 1);
> +    s->regs[0xe7] = 0xfe;
>     /* Serial port 2 base addr 0x2f8-f */
> -    vt82c686b_superio_cfg_write(s, 0, 0xe8, 1);
> -    vt82c686b_superio_cfg_write(s, 1, 0xbe, 1);
> +    s->regs[0xe8] = 0xbe;
>
> -    vt82c686b_superio_cfg_write(s, 0, 0, 1);
> +    vt82c686b_superio_update(s);
> }
>
> static void vt82c686b_superio_init(Object *obj)
> @@ -429,6 +464,7 @@ static void vt82c686b_superio_class_init(ObjectClass *klass, void *data)
>     sc->parallel.count = 1;
>     sc->ide.count = 0; /* emulated by via-ide */
>     sc->floppy.count = 1;
> +    dc->vmsd = &vmstate_vt82c686b_superio;
> }
>
> static const TypeInfo vt82c686b_superio_info = {
> @@ -443,6 +479,33 @@ static const TypeInfo vt82c686b_superio_info = {
>
> #define TYPE_VT8231_SUPERIO "vt8231-superio"
>
> +static void vt8231_superio_update(ViaSuperIOState *s)
> +{
> +    isa_parallel_set_enabled(s->superio.parallel[0],
> +                             (s->regs[0xf2] & 0x3) != 3);
> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xf2] & BIT(2));
> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xf2] & BIT(4));
> +
> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xf4] & 0xfe) << 2);
> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xf6] << 2);
> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xf7] & 0xfc) << 2);
> +}
> +
> +static int vmstate_vt8231_superio_post_load(void *opaque, int version_id)
> +{
> +    ViaSuperIOState *s = opaque;
> +
> +    vt8231_superio_update(s);
> +
> +    return 0;
> +}
> +
> +static const VMStateDescription vmstate_vt8231_superio = {
> +    .name = "vt8231_superio",
> +    .version_id = 1,
> +    .post_load = vmstate_vt8231_superio_post_load,
> +};
> +
> static void vt8231_superio_cfg_write(void *opaque, hwaddr addr,
>                                      uint64_t data, unsigned size)
> {
> @@ -465,6 +528,12 @@ static void vt8231_superio_cfg_write(void *opaque, hwaddr addr,
>     case 0xfd:
>         /* ignore write to read only registers */
>         return;
> +    case 0xf2:
> +    case 0xf4:
> +    case 0xf6 ... 0xf7:
> +        sc->regs[idx] = data;
> +        vt8231_superio_update(sc);
> +        return;
>     default:
>         qemu_log_mask(LOG_UNIMP,
>                       "via_superio_cfg: unimplemented register 0x%x\n", idx);
> @@ -493,19 +562,15 @@ static void vt8231_superio_reset(DeviceState *dev)
>     /* Device revision */
>     s->regs[0xf1] = 0x01;
>     /* Function select - all disabled */
> -    vt8231_superio_cfg_write(s, 0, 0xf2, 1);
> -    vt8231_superio_cfg_write(s, 1, 0x03, 1);
> +    s->regs[0xf2] = 0x03;
>     /* Serial port base addr */
> -    vt8231_superio_cfg_write(s, 0, 0xf4, 1);
> -    vt8231_superio_cfg_write(s, 1, 0xfe, 1);
> +    s->regs[0xf4] = 0xfe;
>     /* Parallel port base addr */
> -    vt8231_superio_cfg_write(s, 0, 0xf6, 1);
> -    vt8231_superio_cfg_write(s, 1, 0xde, 1);
> +    s->regs[0xf6] = 0xde;
>     /* Floppy ctrl base addr */
> -    vt8231_superio_cfg_write(s, 0, 0xf7, 1);
> -    vt8231_superio_cfg_write(s, 1, 0xfc, 1);
> +    s->regs[0xf7] = 0xfc;
>
> -    vt8231_superio_cfg_write(s, 0, 0, 1);
> +    vt8231_superio_update(s);
> }
>
> static void vt8231_superio_init(Object *obj)
> @@ -513,12 +578,6 @@ static void vt8231_superio_init(Object *obj)
>     VIA_SUPERIO(obj)->io_ops = &vt8231_superio_cfg_ops;
> }
>
> -static uint16_t vt8231_superio_serial_iobase(ISASuperIODevice *sio,
> -                                             uint8_t index)
> -{
> -        return 0x2f8; /* FIXME: This should be settable via registers f2-f4 */
> -}
> -
> static void vt8231_superio_class_init(ObjectClass *klass, void *data)
> {
>     DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -526,10 +585,10 @@ static void vt8231_superio_class_init(ObjectClass *klass, void *data)
>
>     dc->reset = vt8231_superio_reset;
>     sc->serial.count = 1;
> -    sc->serial.get_iobase = vt8231_superio_serial_iobase;
>     sc->parallel.count = 1;
>     sc->ide.count = 0; /* emulated by via-ide */
>     sc->floppy.count = 1;
> +    dc->vmsd = &vmstate_vt8231_superio;
> }
>
> static const TypeInfo vt8231_superio_info = {
>

Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>> The VIA south bridges are able to relocate and toggle (enable or disable) their
>> SuperI/O functions. So far this is hardcoded such that all functions are always
>> enabled and are located at fixed addresses.
>> 
>> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
>> and issue an error in case of a conflict. Since the functions are enabled on
>> reset, conflicts are always detected. Prevent that by implementing relocation
>> and toggling of the SuperI/O functions.
>> 
>> Note that all SuperI/O functions are now deactivated upon reset (except for
>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
>> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
>> no -bios is given -- to configure the functions accordingly.
>
>Pegasos2 emulates firmware when no -bios is given, this was explained in previos commit so maybe not needed to be explained it here again so you could drop the comment between -- -- but I don't mind.
>
>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>> ---
>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>> 1 file changed, 90 insertions(+), 31 deletions(-)
>> 
>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>> index 9c2333a277..be202d23cf 100644
>> --- a/hw/isa/vt82c686.c
>> +++ b/hw/isa/vt82c686.c
>> @@ -15,6 +15,9 @@
>> 
>> #include "qemu/osdep.h"
>> #include "hw/isa/vt82c686.h"
>> +#include "hw/block/fdc.h"
>> +#include "hw/char/parallel-isa.h"
>> +#include "hw/char/serial.h"
>> #include "hw/pci/pci.h"
>> #include "hw/qdev-properties.h"
>> #include "hw/ide/pci.h"
>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>> 
>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>> 
>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>> +{
>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>> +                             (s->regs[0xe2] & 0x3) != 3);
>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>> +
>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
>> +}
>
>I wonder if some code duplication could be saved by adding a shared via_superio_update() for this further up in the abstract via-superio class instead of this method and vt8231_superio_update() below. This common method in abstract class would need to handle the differences which seem to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. These could either be handled by adding function parameters or fields to ViaSuperIOState for this that the subclasses can set and the method check. (Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how many ports are there then can have a for loop for those that would only run once for vt8231).

Only the enable bits and the parallel port base address line up, the serial port(s) and the floppy would need special treatment. Not worth it IMO.

>
>> +static int vmstate_vt82c686b_superio_post_load(void *opaque, int version_id)
>> +{
>> +    ViaSuperIOState *s = opaque;
>> +
>> +    vt82c686b_superio_update(s);
>> +
>> +    return 0;
>
>You could lose some blank lines here. You seem to love them, half of your cover letter is just blank lines :-)

Yes, I want people to see the light rather than a wall (of text) ;-)

> but I'm the opposite and like more code to fit in one screen even on todays displays that are wider than tall. So this funciton would take less space without blank lines. (Even the local variable may not be necessary as you don't access any fields within and void * should just cast without a warning but for spelling out the desired type as a reminder I'm ok with leaving that but no excessive blank lines please if you don't mind that much.)

In this case I'll remove the s variable and the blank line above the return if that's so important to you.

Best regards,
Bernhard
>
>Regards,
>BALATON Zoltan
>
>> +}
>> +
>> +static const VMStateDescription vmstate_vt82c686b_superio = {
>> +    .name = "vt82c686b_superio",
>> +    .version_id = 1,
>> +    .post_load = vmstate_vt82c686b_superio_post_load,
>> +};
>> +
>> static void vt82c686b_superio_cfg_write(void *opaque, hwaddr addr,
>>                                         uint64_t data, unsigned size)
>> {
>> @@ -368,7 +400,11 @@ static void vt82c686b_superio_cfg_write(void *opaque, hwaddr addr,
>>     case 0xfd ... 0xff:
>>         /* ignore write to read only registers */
>>         return;
>> -    /* case 0xe6 ... 0xe8: Should set base port of parallel and serial */
>> +    case 0xe2 ... 0xe3:
>> +    case 0xe6 ... 0xe8:
>> +        sc->regs[idx] = data;
>> +        vt82c686b_superio_update(sc);
>> +        return;
>>     default:
>>         qemu_log_mask(LOG_UNIMP,
>>                       "via_superio_cfg: unimplemented register 0x%x\n", idx);
>> @@ -393,25 +429,24 @@ static void vt82c686b_superio_reset(DeviceState *dev)
>> 
>>     memset(s->regs, 0, sizeof(s->regs));
>>     /* Device ID */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe0, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0x3c, 1);
>> -    /* Function select - all disabled */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe2, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0x03, 1);
>> +    s->regs[0xe0] = 0x3c;
>> +    /*
>> +     * Function select - only serial enabled
>> +     * Fuloong 2e's rescue-yl prints to the serial console w/o enabling it. This
>> +     * suggests that the serial ports are enabled by default, so override the
>> +     * datasheet.
>> +     */
>> +    s->regs[0xe2] = 0x0f;
>>     /* Floppy ctrl base addr 0x3f0-7 */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe3, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xfc, 1);
>> +    s->regs[0xe3] = 0xfc;
>>     /* Parallel port base addr 0x378-f */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe6, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xde, 1);
>> +    s->regs[0xe6] = 0xde;
>>     /* Serial port 1 base addr 0x3f8-f */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe7, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xfe, 1);
>> +    s->regs[0xe7] = 0xfe;
>>     /* Serial port 2 base addr 0x2f8-f */
>> -    vt82c686b_superio_cfg_write(s, 0, 0xe8, 1);
>> -    vt82c686b_superio_cfg_write(s, 1, 0xbe, 1);
>> +    s->regs[0xe8] = 0xbe;
>> 
>> -    vt82c686b_superio_cfg_write(s, 0, 0, 1);
>> +    vt82c686b_superio_update(s);
>> }
>> 
>> static void vt82c686b_superio_init(Object *obj)
>> @@ -429,6 +464,7 @@ static void vt82c686b_superio_class_init(ObjectClass *klass, void *data)
>>     sc->parallel.count = 1;
>>     sc->ide.count = 0; /* emulated by via-ide */
>>     sc->floppy.count = 1;
>> +    dc->vmsd = &vmstate_vt82c686b_superio;
>> }
>> 
>> static const TypeInfo vt82c686b_superio_info = {
>> @@ -443,6 +479,33 @@ static const TypeInfo vt82c686b_superio_info = {
>> 
>> #define TYPE_VT8231_SUPERIO "vt8231-superio"
>> 
>> +static void vt8231_superio_update(ViaSuperIOState *s)
>> +{
>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>> +                             (s->regs[0xf2] & 0x3) != 3);
>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xf2] & BIT(2));
>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xf2] & BIT(4));
>> +
>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xf4] & 0xfe) << 2);
>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xf6] << 2);
>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xf7] & 0xfc) << 2);
>> +}
>> +
>> +static int vmstate_vt8231_superio_post_load(void *opaque, int version_id)
>> +{
>> +    ViaSuperIOState *s = opaque;
>> +
>> +    vt8231_superio_update(s);
>> +
>> +    return 0;
>> +}
>> +
>> +static const VMStateDescription vmstate_vt8231_superio = {
>> +    .name = "vt8231_superio",
>> +    .version_id = 1,
>> +    .post_load = vmstate_vt8231_superio_post_load,
>> +};
>> +
>> static void vt8231_superio_cfg_write(void *opaque, hwaddr addr,
>>                                      uint64_t data, unsigned size)
>> {
>> @@ -465,6 +528,12 @@ static void vt8231_superio_cfg_write(void *opaque, hwaddr addr,
>>     case 0xfd:
>>         /* ignore write to read only registers */
>>         return;
>> +    case 0xf2:
>> +    case 0xf4:
>> +    case 0xf6 ... 0xf7:
>> +        sc->regs[idx] = data;
>> +        vt8231_superio_update(sc);
>> +        return;
>>     default:
>>         qemu_log_mask(LOG_UNIMP,
>>                       "via_superio_cfg: unimplemented register 0x%x\n", idx);
>> @@ -493,19 +562,15 @@ static void vt8231_superio_reset(DeviceState *dev)
>>     /* Device revision */
>>     s->regs[0xf1] = 0x01;
>>     /* Function select - all disabled */
>> -    vt8231_superio_cfg_write(s, 0, 0xf2, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0x03, 1);
>> +    s->regs[0xf2] = 0x03;
>>     /* Serial port base addr */
>> -    vt8231_superio_cfg_write(s, 0, 0xf4, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0xfe, 1);
>> +    s->regs[0xf4] = 0xfe;
>>     /* Parallel port base addr */
>> -    vt8231_superio_cfg_write(s, 0, 0xf6, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0xde, 1);
>> +    s->regs[0xf6] = 0xde;
>>     /* Floppy ctrl base addr */
>> -    vt8231_superio_cfg_write(s, 0, 0xf7, 1);
>> -    vt8231_superio_cfg_write(s, 1, 0xfc, 1);
>> +    s->regs[0xf7] = 0xfc;
>> 
>> -    vt8231_superio_cfg_write(s, 0, 0, 1);
>> +    vt8231_superio_update(s);
>> }
>> 
>> static void vt8231_superio_init(Object *obj)
>> @@ -513,12 +578,6 @@ static void vt8231_superio_init(Object *obj)
>>     VIA_SUPERIO(obj)->io_ops = &vt8231_superio_cfg_ops;
>> }
>> 
>> -static uint16_t vt8231_superio_serial_iobase(ISASuperIODevice *sio,
>> -                                             uint8_t index)
>> -{
>> -        return 0x2f8; /* FIXME: This should be settable via registers f2-f4 */
>> -}
>> -
>> static void vt8231_superio_class_init(ObjectClass *klass, void *data)
>> {
>>     DeviceClass *dc = DEVICE_CLASS(klass);
>> @@ -526,10 +585,10 @@ static void vt8231_superio_class_init(ObjectClass *klass, void *data)
>> 
>>     dc->reset = vt8231_superio_reset;
>>     sc->serial.count = 1;
>> -    sc->serial.get_iobase = vt8231_superio_serial_iobase;
>>     sc->parallel.count = 1;
>>     sc->ide.count = 0; /* emulated by via-ide */
>>     sc->floppy.count = 1;
>> +    dc->vmsd = &vmstate_vt8231_superio;
>> }
>> 
>> static const TypeInfo vt8231_superio_info = {
>>

On Tue, 19 Dec 2023, Bernhard Beschow wrote:
> Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>> On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>>> The VIA south bridges are able to relocate and toggle (enable or disable) their
>>> SuperI/O functions. So far this is hardcoded such that all functions are always
>>> enabled and are located at fixed addresses.
>>>
>>> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
>>> and issue an error in case of a conflict. Since the functions are enabled on
>>> reset, conflicts are always detected. Prevent that by implementing relocation
>>> and toggling of the SuperI/O functions.
>>>
>>> Note that all SuperI/O functions are now deactivated upon reset (except for
>>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
>>> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
>>> no -bios is given -- to configure the functions accordingly.
>>
>> Pegasos2 emulates firmware when no -bios is given, this was explained in previos commit so maybe not needed to be explained it here again so you could drop the comment between -- -- but I don't mind.
>>
>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>> ---
>>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>>> 1 file changed, 90 insertions(+), 31 deletions(-)
>>>
>>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>>> index 9c2333a277..be202d23cf 100644
>>> --- a/hw/isa/vt82c686.c
>>> +++ b/hw/isa/vt82c686.c
>>> @@ -15,6 +15,9 @@
>>>
>>> #include "qemu/osdep.h"
>>> #include "hw/isa/vt82c686.h"
>>> +#include "hw/block/fdc.h"
>>> +#include "hw/char/parallel-isa.h"
>>> +#include "hw/char/serial.h"
>>> #include "hw/pci/pci.h"
>>> #include "hw/qdev-properties.h"
>>> #include "hw/ide/pci.h"
>>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>>>
>>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>>>
>>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>>> +{
>>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>>> +                             (s->regs[0xe2] & 0x3) != 3);
>>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>>> +
>>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
>>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
>>> +}
>>
>> I wonder if some code duplication could be saved by adding a shared via_superio_update() for this further up in the abstract via-superio class instead of this method and vt8231_superio_update() below. This common method in abstract class would need to handle the differences which seem to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. These could either be handled by adding function parameters or fields to ViaSuperIOState for this that the subclasses can set and the method check. (Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how many ports are there then can have a for loop for those that would only run once for vt8231).
>
> Only the enable bits and the parallel port base address line up, the serial port(s) and the floppy would need special treatment. Not worth it IMO.
>
>>
>>> +static int vmstate_vt82c686b_superio_post_load(void *opaque, int version_id)
>>> +{
>>> +    ViaSuperIOState *s = opaque;
>>> +
>>> +    vt82c686b_superio_update(s);
>>> +
>>> +    return 0;
>>
>> You could lose some blank lines here. You seem to love them, half of your cover letter is just blank lines :-)
>
> Yes, I want people to see the light rather than a wall (of text) ;-)

Well, information is in the text and anything else just distracts from it. 
I guess you can configure your editor to present text the way you like but 
it's hard for me or others to get rid of hard formatting so it's better to 
only add the needed text.

>> but I'm the opposite and like more code to fit in one screen even on todays displays that are wider than tall. So this funciton would take less space without blank lines. (Even the local variable may not be necessary as you don't access any fields within and void * should just cast without a warning but for spelling out the desired type as a reminder I'm ok with leaving that but no excessive blank lines please if you don't mind that much.)
>
> In this case I'll remove the s variable and the blank line above the return if that's so important to you.

I think it's simper and more readable that way that's why it's important 
to me.

Regards,
BALATON Zoltan

On Tue, 19 Dec 2023, Bernhard Beschow wrote:
> Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>> On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>>> The VIA south bridges are able to relocate and toggle (enable or disable) their
>>> SuperI/O functions. So far this is hardcoded such that all functions are always
>>> enabled and are located at fixed addresses.
>>>
>>> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
>>> and issue an error in case of a conflict. Since the functions are enabled on
>>> reset, conflicts are always detected. Prevent that by implementing relocation
>>> and toggling of the SuperI/O functions.
>>>
>>> Note that all SuperI/O functions are now deactivated upon reset (except for
>>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
>>> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
>>> no -bios is given -- to configure the functions accordingly.
>>
>> Pegasos2 emulates firmware when no -bios is given, this was explained in previos commit so maybe not needed to be explained it here again so you could drop the comment between -- -- but I don't mind.
>>
>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>> ---
>>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>>> 1 file changed, 90 insertions(+), 31 deletions(-)
>>>
>>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>>> index 9c2333a277..be202d23cf 100644
>>> --- a/hw/isa/vt82c686.c
>>> +++ b/hw/isa/vt82c686.c
>>> @@ -15,6 +15,9 @@
>>>
>>> #include "qemu/osdep.h"
>>> #include "hw/isa/vt82c686.h"
>>> +#include "hw/block/fdc.h"
>>> +#include "hw/char/parallel-isa.h"
>>> +#include "hw/char/serial.h"
>>> #include "hw/pci/pci.h"
>>> #include "hw/qdev-properties.h"
>>> #include "hw/ide/pci.h"
>>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>>>
>>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>>>
>>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>>> +{
>>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>>> +                             (s->regs[0xe2] & 0x3) != 3);
>>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>>> +
>>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
>>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
>>> +}
>>
>> I wonder if some code duplication could be saved by adding a shared via_superio_update() for this further up in the abstract via-superio class instead of this method and vt8231_superio_update() below. This common method in abstract class would need to handle the differences which seem to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. These could either be handled by adding function parameters or fields to ViaSuperIOState for this that the subclasses can set and the method check. (Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how many ports are there then can have a for loop for those that would only run once for vt8231).
>
> Only the enable bits and the parallel port base address line up, the 
> serial port(s) and the floppy would need special treatment. Not worth it 
> IMO.

Missed this part in previous reply. The serial ports would be taken care 
of by a loop for number of ports so only the floppy needs an if which 
could also use the number of serial ports for lack of better way to 
distinguish these cips easily. Number of ports are in the superio class 
which you could get with ISA_SUPERIO_GET_CLASS (see via_superio_realize) 
then serial.count would be 2 for 686b and 1 for 8231.

But now I think another way may be better that is to drop the 
superio_update function as this updates all functions on writing any 
register unnecessarily and put the lines from it in the 
vt*_superio_cfg_write() functions under the separate cases. This was the 
original intent, that's why the reset function goes through that write 
function so it can enable/disable functions. That way you could apply mask 
on write so via_superio_cfg_read() would return 0 bits as 0 (although the 
data sheet is not clear about what real chip does, just says these must be 
0 not that it's enforced but if we enforce that it's probably better to 
return the effective value on read as well). Then when state saving is 
added in separate patch you can have a similar function as 
vt82c686b_superio_reset() (or rename that to update and make it use 
regs[xx] instead of constant values and call that from reset after setting 
regs values like you did here. But that needs more thought as the vmstate 
added by this patch is incomplete and would not work so you could just 
drop it for now and add it later with also adding other necessary state as 
well. The idea was to implement the chip first then add state saving so we 
don't need to bother with breaking it until we have a good enough 
implementation. So far the state saving there is just left over from the 
old model which never worked and only left there for reminder but only 
wanted to fix once the model is complete enough.

So I think for now you could drop vmstate stuff and distribute the 
superio_update lines in the superio_cfg_write functions so each reg only 
controls the function it should control. Then when vmstate saving is added 
later it could reuse superio_reset as an update function adding a new 
reset func setting reg values and calling the old reset/new update 
function. Does that make sense?

Regards,
BALATON Zoltan

Am 24. Dezember 2023 00:51:53 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Tue, 19 Dec 2023, Bernhard Beschow wrote:
>> Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>>> On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>>>> The VIA south bridges are able to relocate and toggle (enable or disable) their
>>>> SuperI/O functions. So far this is hardcoded such that all functions are always
>>>> enabled and are located at fixed addresses.
>>>> 
>>>> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
>>>> and issue an error in case of a conflict. Since the functions are enabled on
>>>> reset, conflicts are always detected. Prevent that by implementing relocation
>>>> and toggling of the SuperI/O functions.
>>>> 
>>>> Note that all SuperI/O functions are now deactivated upon reset (except for
>>>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
>>>> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
>>>> no -bios is given -- to configure the functions accordingly.
>>> 
>>> Pegasos2 emulates firmware when no -bios is given, this was explained in previos commit so maybe not needed to be explained it here again so you could drop the comment between -- -- but I don't mind.
>>> 
>>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>>> ---
>>>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>>>> 1 file changed, 90 insertions(+), 31 deletions(-)
>>>> 
>>>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>>>> index 9c2333a277..be202d23cf 100644
>>>> --- a/hw/isa/vt82c686.c
>>>> +++ b/hw/isa/vt82c686.c
>>>> @@ -15,6 +15,9 @@
>>>> 
>>>> #include "qemu/osdep.h"
>>>> #include "hw/isa/vt82c686.h"
>>>> +#include "hw/block/fdc.h"
>>>> +#include "hw/char/parallel-isa.h"
>>>> +#include "hw/char/serial.h"
>>>> #include "hw/pci/pci.h"
>>>> #include "hw/qdev-properties.h"
>>>> #include "hw/ide/pci.h"
>>>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>>>> 
>>>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>>>> 
>>>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>>>> +{
>>>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>>>> +                             (s->regs[0xe2] & 0x3) != 3);
>>>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>>>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>>>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>>>> +
>>>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>>>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>>>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
>>>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
>>>> +}
>>> 
>>> I wonder if some code duplication could be saved by adding a shared via_superio_update() for this further up in the abstract via-superio class instead of this method and vt8231_superio_update() below. This common method in abstract class would need to handle the differences which seem to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. These could either be handled by adding function parameters or fields to ViaSuperIOState for this that the subclasses can set and the method check. (Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how many ports are there then can have a for loop for those that would only run once for vt8231).
>> 
>> Only the enable bits and the parallel port base address line up, the serial port(s) and the floppy would need special treatment. Not worth it IMO.
>
>Missed this part in previous reply. The serial ports would be taken care of by a loop for number of ports so only the floppy needs an if which could also use the number of serial ports for lack of better way to distinguish these cips easily. Number of ports are in the superio class which you could get with ISA_SUPERIO_GET_CLASS (see via_superio_realize) then serial.count would be 2 for 686b and 1 for 8231.

I'm not very convinced about telling the device models apart by their number of sub devices. So let's omit this part for now.

>
>But now I think another way may be better that is to drop the superio_update function as this updates all functions on writing any register unnecessarily and put the lines from it in the vt*_superio_cfg_write() functions under the separate cases. This was the original intent, that's why the reset function goes through that write function so it can enable/disable functions. That way you could apply mask on write so via_superio_cfg_read() would return 0 bits as 0 (although the data sheet is not clear about what real chip does, just says these must be 0 not that it's enforced but if we enforce that it's probably better to return the effective value on read as well). Then when state saving is added in separate patch you can have a similar function as vt82c686b_superio_reset() (or rename that to update and make it use regs[xx] instead of constant values and call that from reset after setting regs values like you did here. But that needs more thought as the vmstate added by this patch is incomplete and would not work so you could just drop it for now and add it later with also adding other necessary state as well. The idea was to implement the chip first then add state saving so we don't need to bother with breaking it until we have a good enough implementation. So far the state saving there is just left over from the old model which never worked and only left there for reminder but only wanted to fix once the model is complete enough.

Indeed, the patch obviously does too much if it misses details in vmstate. Let's omit vmstate handling for now and go with your suggestion.

Any other comments from your side before the next iteration?

>
>So I think for now you could drop vmstate stuff and distribute the superio_update lines in the superio_cfg_write functions so each reg only controls the function it should control. Then when vmstate saving is added later it could reuse superio_reset as an update function adding a new reset func setting reg values and calling the old reset/new update function. Does that make sense?

What I don't like about the vt*_superio_cfg_write() being called during reset is the trace logs they produce. They are hard to tell apart from guests poking these registers, especially during reboot. So I wonder if this could be addressed when implementing vmstate handling as you suggest. Not too big of a deal, though.

Best regards,
Bernhard

>
>Regards,
>BALATON Zoltan

On Tue, 2 Jan 2024, Bernhard Beschow wrote:
> Am 24. Dezember 2023 00:51:53 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>> On Tue, 19 Dec 2023, Bernhard Beschow wrote:
>>> Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>>>> On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>>>>> The VIA south bridges are able to relocate and toggle (enable or disable) their
>>>>> SuperI/O functions. So far this is hardcoded such that all functions are always
>>>>> enabled and are located at fixed addresses.
>>>>>
>>>>> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
>>>>> and issue an error in case of a conflict. Since the functions are enabled on
>>>>> reset, conflicts are always detected. Prevent that by implementing relocation
>>>>> and toggling of the SuperI/O functions.
>>>>>
>>>>> Note that all SuperI/O functions are now deactivated upon reset (except for
>>>>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
>>>>> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
>>>>> no -bios is given -- to configure the functions accordingly.
>>>>
>>>> Pegasos2 emulates firmware when no -bios is given, this was explained in previos commit so maybe not needed to be explained it here again so you could drop the comment between -- -- but I don't mind.
>>>>
>>>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>>>> ---
>>>>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>>>>> 1 file changed, 90 insertions(+), 31 deletions(-)
>>>>>
>>>>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>>>>> index 9c2333a277..be202d23cf 100644
>>>>> --- a/hw/isa/vt82c686.c
>>>>> +++ b/hw/isa/vt82c686.c
>>>>> @@ -15,6 +15,9 @@
>>>>>
>>>>> #include "qemu/osdep.h"
>>>>> #include "hw/isa/vt82c686.h"
>>>>> +#include "hw/block/fdc.h"
>>>>> +#include "hw/char/parallel-isa.h"
>>>>> +#include "hw/char/serial.h"
>>>>> #include "hw/pci/pci.h"
>>>>> #include "hw/qdev-properties.h"
>>>>> #include "hw/ide/pci.h"
>>>>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>>>>>
>>>>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>>>>>
>>>>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>>>>> +{
>>>>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>>>>> +                             (s->regs[0xe2] & 0x3) != 3);
>>>>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>>>>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>>>>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>>>>> +
>>>>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>>>>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>>>>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
>>>>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
>>>>> +}
>>>>
>>>> I wonder if some code duplication could be saved by adding a shared via_superio_update() for this further up in the abstract via-superio class instead of this method and vt8231_superio_update() below. This common method in abstract class would need to handle the differences which seem to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. These could either be handled by adding function parameters or fields to ViaSuperIOState for this that the subclasses can set and the method check. (Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how many ports are there then can have a for loop for those that would only run once for vt8231).
>>>
>>> Only the enable bits and the parallel port base address line up, the serial port(s) and the floppy would need special treatment. Not worth it IMO.
>>
>> Missed this part in previous reply. The serial ports would be taken care of by a loop for number of ports so only the floppy needs an if which could also use the number of serial ports for lack of better way to distinguish these cips easily. Number of ports are in the superio class which you could get with ISA_SUPERIO_GET_CLASS (see via_superio_realize) then serial.count would be 2 for 686b and 1 for 8231.
>
> I'm not very convinced about telling the device models apart by their number of sub devices. So let's omit this part for now.
>
>>
>> But now I think another way may be better that is to drop the 
>> superio_update function as this updates all functions on writing any 
>> register unnecessarily and put the lines from it in the 
>> vt*_superio_cfg_write() functions under the separate cases. This was 
>> the original intent, that's why the reset function goes through that 
>> write function so it can enable/disable functions. That way you could 
>> apply mask on write so via_superio_cfg_read() would return 0 bits as 0 
>> (although the data sheet is not clear about what real chip does, just 
>> says these must be 0 not that it's enforced but if we enforce that it's 
>> probably better to return the effective value on read as well). Then 
>> when state saving is added in separate patch you can have a similar 
>> function as vt82c686b_superio_reset() (or rename that to update and 
>> make it use regs[xx] instead of constant values and call that from 
>> reset after setting regs values like you did here. But that needs more 
>> thought as the vmstate added by this patch is incomplete and would not 
>> work so you could just drop it for now and add it later with also 
>> adding other necessary state as well. The idea was to implement the 
>> chip first then add state saving so we don't need to bother with 
>> breaking it until we have a good enough implementation. So far the 
>> state saving there is just left over from the old model which never 
>> worked and only left there for reminder but only wanted to fix once the 
>> model is complete enough.
>
> Indeed, the patch obviously does too much if it misses details in vmstate. Let's omit vmstate handling for now and go with your suggestion.
>
> Any other comments from your side before the next iteration?

Nothing else from me unless Philippe has something to add. You can keep a 
common function in the abstract via superclass for handling the enable 
bits in the function select register to reduce code duplication as those 
match and handle the address setting separately.

>> So I think for now you could drop vmstate stuff and distribute the 
>> superio_update lines in the superio_cfg_write functions so each reg 
>> only controls the function it should control. Then when vmstate saving 
>> is added later it could reuse superio_reset as an update function 
>> adding a new reset func setting reg values and calling the old 
>> reset/new update function. Does that make sense?
>
> What I don't like about the vt*_superio_cfg_write() being called during 
> reset is the trace logs they produce. They are hard to tell apart from 
> guests poking these registers, especially during reboot. So I wonder if 
> this could be addressed when implementing vmstate handling as you 
> suggest. Not too big of a deal, though.

An easy way around that is to start qemu with -S then these setup logs 
come before qemu stops then logs from guest actions will be printed after 
continue|c in monitor.

Regards,
BALATON Zoltan

Am 3. Januar 2024 12:26:07 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>On Tue, 2 Jan 2024, Bernhard Beschow wrote:
>> Am 24. Dezember 2023 00:51:53 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>>> On Tue, 19 Dec 2023, Bernhard Beschow wrote:
>>>> Am 19. Dezember 2023 00:26:15 UTC schrieb BALATON Zoltan <balaton@eik.bme.hu>:
>>>>> On Mon, 18 Dec 2023, Bernhard Beschow wrote:
>>>>>> The VIA south bridges are able to relocate and toggle (enable or disable) their
>>>>>> SuperI/O functions. So far this is hardcoded such that all functions are always
>>>>>> enabled and are located at fixed addresses.
>>>>>> 
>>>>>> Some PC BIOSes seem to probe for I/O occupancy before activating such a function
>>>>>> and issue an error in case of a conflict. Since the functions are enabled on
>>>>>> reset, conflicts are always detected. Prevent that by implementing relocation
>>>>>> and toggling of the SuperI/O functions.
>>>>>> 
>>>>>> Note that all SuperI/O functions are now deactivated upon reset (except for
>>>>>> VT82C686B's serial ports where Fuloong 2e's rescue-yl seems to expect them to be
>>>>>> enabled by default). Rely on firmware -- or in case of pegasos2 on board code if
>>>>>> no -bios is given -- to configure the functions accordingly.
>>>>> 
>>>>> Pegasos2 emulates firmware when no -bios is given, this was explained in previos commit so maybe not needed to be explained it here again so you could drop the comment between -- -- but I don't mind.
>>>>> 
>>>>>> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
>>>>>> ---
>>>>>> hw/isa/vt82c686.c | 121 ++++++++++++++++++++++++++++++++++------------
>>>>>> 1 file changed, 90 insertions(+), 31 deletions(-)
>>>>>> 
>>>>>> diff --git a/hw/isa/vt82c686.c b/hw/isa/vt82c686.c
>>>>>> index 9c2333a277..be202d23cf 100644
>>>>>> --- a/hw/isa/vt82c686.c
>>>>>> +++ b/hw/isa/vt82c686.c
>>>>>> @@ -15,6 +15,9 @@
>>>>>> 
>>>>>> #include "qemu/osdep.h"
>>>>>> #include "hw/isa/vt82c686.h"
>>>>>> +#include "hw/block/fdc.h"
>>>>>> +#include "hw/char/parallel-isa.h"
>>>>>> +#include "hw/char/serial.h"
>>>>>> #include "hw/pci/pci.h"
>>>>>> #include "hw/qdev-properties.h"
>>>>>> #include "hw/ide/pci.h"
>>>>>> @@ -343,6 +346,35 @@ static const TypeInfo via_superio_info = {
>>>>>> 
>>>>>> #define TYPE_VT82C686B_SUPERIO "vt82c686b-superio"
>>>>>> 
>>>>>> +static void vt82c686b_superio_update(ViaSuperIOState *s)
>>>>>> +{
>>>>>> +    isa_parallel_set_enabled(s->superio.parallel[0],
>>>>>> +                             (s->regs[0xe2] & 0x3) != 3);
>>>>>> +    isa_serial_set_enabled(s->superio.serial[0], s->regs[0xe2] & BIT(2));
>>>>>> +    isa_serial_set_enabled(s->superio.serial[1], s->regs[0xe2] & BIT(3));
>>>>>> +    isa_fdc_set_enabled(s->superio.floppy, s->regs[0xe2] & BIT(4));
>>>>>> +
>>>>>> +    isa_fdc_set_iobase(s->superio.floppy, (s->regs[0xe3] & 0xfc) << 2);
>>>>>> +    isa_parallel_set_iobase(s->superio.parallel[0], s->regs[0xe6] << 2);
>>>>>> +    isa_serial_set_iobase(s->superio.serial[0], (s->regs[0xe7] & 0xfe) << 2);
>>>>>> +    isa_serial_set_iobase(s->superio.serial[1], (s->regs[0xe8] & 0xfe) << 2);
>>>>>> +}
>>>>> 
>>>>> I wonder if some code duplication could be saved by adding a shared via_superio_update() for this further up in the abstract via-superio class instead of this method and vt8231_superio_update() below. This common method in abstract class would need to handle the differences which seem to be reg addresses offset by 0x10 and VT8231 having only 1 serial port. These could either be handled by adding function parameters or fields to ViaSuperIOState for this that the subclasses can set and the method check. (Such as reg base=0xe2 for vt82c686 and 0xf2 for vt8231 and num_serial or similar for how many ports are there then can have a for loop for those that would only run once for vt8231).
>>>> 
>>>> Only the enable bits and the parallel port base address line up, the serial port(s) and the floppy would need special treatment. Not worth it IMO.
>>> 
>>> Missed this part in previous reply. The serial ports would be taken care of by a loop for number of ports so only the floppy needs an if which could also use the number of serial ports for lack of better way to distinguish these cips easily. Number of ports are in the superio class which you could get with ISA_SUPERIO_GET_CLASS (see via_superio_realize) then serial.count would be 2 for 686b and 1 for 8231.
>> 
>> I'm not very convinced about telling the device models apart by their number of sub devices. So let's omit this part for now.
>> 
>>> 
>>> But now I think another way may be better that is to drop the superio_update function as this updates all functions on writing any register unnecessarily and put the lines from it in the vt*_superio_cfg_write() functions under the separate cases. This was the original intent, that's why the reset function goes through that write function so it can enable/disable functions. That way you could apply mask on write so via_superio_cfg_read() would return 0 bits as 0 (although the data sheet is not clear about what real chip does, just says these must be 0 not that it's enforced but if we enforce that it's probably better to return the effective value on read as well). Then when state saving is added in separate patch you can have a similar function as vt82c686b_superio_reset() (or rename that to update and make it use regs[xx] instead of constant values and call that from reset after setting regs values like you did here. But that needs more thought as the vmstate added by this patch is incomplete and would not work so you could just drop it for now and add it later with also adding other necessary state as well. The idea was to implement the chip first then add state saving so we don't need to bother with breaking it until we have a good enough implementation. So far the state saving there is just left over from the old model which never worked and only left there for reminder but only wanted to fix once the model is complete enough.
>> 
>> Indeed, the patch obviously does too much if it misses details in vmstate. Let's omit vmstate handling for now and go with your suggestion.
>> 
>> Any other comments from your side before the next iteration?
>
>Nothing else from me unless Philippe has something to add. You can keep a common function in the abstract via superclass for handling the enable bits in the function select register to reduce code duplication as those match and handle the address setting separately.

I've just sent v4.

Best regards,
Bernhard

>
>>> So I think for now you could drop vmstate stuff and distribute the superio_update lines in the superio_cfg_write functions so each reg only controls the function it should control. Then when vmstate saving is added later it could reuse superio_reset as an update function adding a new reset func setting reg values and calling the old reset/new update function. Does that make sense?
>> 
>> What I don't like about the vt*_superio_cfg_write() being called during reset is the trace logs they produce. They are hard to tell apart from guests poking these registers, especially during reboot. So I wonder if this could be addressed when implementing vmstate handling as you suggest. Not too big of a deal, though.
>
>An easy way around that is to start qemu with -S then these setup logs come before qemu stops then logs from guest actions will be printed after continue|c in monitor.
>
>Regards,
>BALATON Zoltan