Re: [Qemu-devel] [PATCH v2 05/10] i2c:pm_smbus: Fix state transfer

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Paolo Bonzini (pbonzini@redhat.com) wrote:
> On 20/08/2018 22:26, minyard@acm.org wrote:
> > From: Corey Minyard <cminyard@mvista.com>
> > 
> > Transfer the state information for the SMBus registers and
> > internal data so it will work on a VM transfer.
> 
> Since the device is mostly unused, I would rather have this in a
> subsection.  This way the format remains backwards-compatible as long as
> the registers have the default values.

Or simpler just wire it to a property and machine type.

Dave

> Also, in case you are interested, a few years ago I was thinking of
> implementing clock stretching; the plan was that clock stretching would
> let you pass host I2C devices down to the guest.  Basically, the I2C
> recv function was changed to accept a callback+opaque, and said callback
> would be invoked later if recv returned -EAGAIN (or something like
> that).  Unfortunately I didn't finish adding support to all the I2C
> controllers when my laptop was stolen, so the patches are lost. :/
> 
> Paolo
> 
> > Signed-off-by: Corey Minyard <cminyard@mvista.com>
> > Cc: Michael S. Tsirkin <mst@redhat.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Cc: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> >  hw/acpi/piix4.c           |  3 ++-
> >  hw/i2c/pm_smbus.c         | 20 ++++++++++++++++++++
> >  hw/i2c/smbus_ich9.c       |  5 +++--
> >  include/hw/i2c/pm_smbus.h |  2 ++
> >  4 files changed, 27 insertions(+), 3 deletions(-)
> > 
> > diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
> > index 6404af5..f8d8d2e 100644
> > --- a/hw/acpi/piix4.c
> > +++ b/hw/acpi/piix4.c
> > @@ -309,7 +309,7 @@ static const VMStateDescription vmstate_cpuhp_state = {
> >   */
> >  static const VMStateDescription vmstate_acpi = {
> >      .name = "piix4_pm",
> > -    .version_id = 3,
> > +    .version_id = 4,
> >      .minimum_version_id = 3,
> >      .minimum_version_id_old = 1,
> >      .load_state_old = acpi_load_old,
> > @@ -320,6 +320,7 @@ static const VMStateDescription vmstate_acpi = {
> >          VMSTATE_UINT16(ar.pm1.evt.en, PIIX4PMState),
> >          VMSTATE_UINT16(ar.pm1.cnt.cnt, PIIX4PMState),
> >          VMSTATE_STRUCT(apm, PIIX4PMState, 0, vmstate_apm, APMState),
> > +        VMSTATE_STRUCT(smb, PIIX4PMState, 4, pmsmb_vmstate, PMSMBus),
> >          VMSTATE_TIMER_PTR(ar.tmr.timer, PIIX4PMState),
> >          VMSTATE_INT64(ar.tmr.overflow_time, PIIX4PMState),
> >          VMSTATE_STRUCT(ar.gpe, PIIX4PMState, 2, vmstate_gpe, ACPIGPE),
> > diff --git a/hw/i2c/pm_smbus.c b/hw/i2c/pm_smbus.c
> > index 32132be..9e11d47 100644
> > --- a/hw/i2c/pm_smbus.c
> > +++ b/hw/i2c/pm_smbus.c
> > @@ -383,6 +383,26 @@ static const MemoryRegionOps pm_smbus_ops = {
> >      .endianness = DEVICE_LITTLE_ENDIAN,
> >  };
> >  
> > +const VMStateDescription pmsmb_vmstate = {
> > +    .name = "pmsmb",
> > +    .version_id = 1,
> > +    .minimum_version_id = 1,
> > +    .fields = (VMStateField[]) {
> > +        VMSTATE_UINT8(smb_stat, PMSMBus),
> > +        VMSTATE_UINT8(smb_ctl, PMSMBus),
> > +        VMSTATE_UINT8(smb_cmd, PMSMBus),
> > +        VMSTATE_UINT8(smb_addr, PMSMBus),
> > +        VMSTATE_UINT8(smb_data0, PMSMBus),
> > +        VMSTATE_UINT8(smb_data1, PMSMBus),
> > +        VMSTATE_UINT32(smb_index, PMSMBus),
> > +        VMSTATE_UINT8_ARRAY(smb_data, PMSMBus, PM_SMBUS_MAX_MSG_SIZE),
> > +        VMSTATE_UINT8(smb_auxctl, PMSMBus),
> > +        VMSTATE_BOOL(i2c_enable, PMSMBus),
> > +        VMSTATE_BOOL(op_done, PMSMBus),
> > +        VMSTATE_END_OF_LIST()
> > +    }
> > +};
> > +
> >  void pm_smbus_init(DeviceState *parent, PMSMBus *smb)
> >  {
> >      smb->op_done = true;
> > diff --git a/hw/i2c/smbus_ich9.c b/hw/i2c/smbus_ich9.c
> > index a66a114..c8b8413 100644
> > --- a/hw/i2c/smbus_ich9.c
> > +++ b/hw/i2c/smbus_ich9.c
> > @@ -45,10 +45,11 @@ typedef struct ICH9SMBState {
> >  
> >  static const VMStateDescription vmstate_ich9_smbus = {
> >      .name = "ich9_smb",
> > -    .version_id = 1,
> > +    .version_id = 2,
> >      .minimum_version_id = 1,
> >      .fields = (VMStateField[]) {
> > -        VMSTATE_PCI_DEVICE(dev, struct ICH9SMBState),
> > +        VMSTATE_PCI_DEVICE(dev, ICH9SMBState),
> > +        VMSTATE_STRUCT(smb, ICH9SMBState, 2, pmsmb_vmstate, PMSMBus),
> >          VMSTATE_END_OF_LIST()
> >      }
> >  };
> > diff --git a/include/hw/i2c/pm_smbus.h b/include/hw/i2c/pm_smbus.h
> > index 99d5489..b1e1970 100644
> > --- a/include/hw/i2c/pm_smbus.h
> > +++ b/include/hw/i2c/pm_smbus.h
> > @@ -33,4 +33,6 @@ typedef struct PMSMBus {
> >  
> >  void pm_smbus_init(DeviceState *parent, PMSMBus *smb);
> >  
> > +extern const VMStateDescription pmsmb_vmstate;
> > +
> >  #endif /* PM_SMBUS_H */
> > 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK