Re: [Qemu-devel] [PATCH v5 2/3] target-i386: reserve RCRB mmio space in ACPI DSDT table

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

On Wed, Jun 24, 2015 at 01:00:49PM -0300, Paulo Alcantara wrote:
> On Wed, 24 Jun 2015 17:11:26 +0200
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Mon, Jun 22, 2015 at 08:10:28PM -0300, Paulo Alcantara wrote:
> > > This block is mapped into memory space, using the Root Complex Base
> > > Address (RCBA) register of the PCI-to-LPC bridge. Accesses in this
> > > space must be limited to 32-(DW) bit quantities. Burst accesses are
> > > not allowed.
> > > 
> > > All Chipset Configuration Registers are located in this 16KiB space.
> > > 
> > > Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>
> > 
> > Can you confirm things just work for you if you drop this patch from
> > the series?
> 
> Hi Michael,
> 
> Yes, everything works. I still see no point of adding it to SSDT
> because OVMF is already setting RCBA to that fixed address and so
> SeaBIOS once my patch is applied. Therefore, there is no no such thing
> like "dynamically programmed by BIOS" either. Although, my host and
> probably yours define the same address in DSDT.
> 
> Given that UEFI and a BIOS implementations are using the same fixed
> address, this patch was done in a hope of not letting the ACPI-aware OS
> using the same address for another BAR or something else thus avoiding
> conflicts.

But does PCI root CRS cover this range? If not - an ACPI aware
OS can't assign PCI BARs in this range really.


> Please, let me know if I'm missing something here. If you want, I can
> send v6 with this patch removed completely.
> 
> (BTW, sorry for the delay. It's holiday here in Brazil and, you know,
> real life happens sometimes :-) )
> 
> Thanks,
> 
> Paulo

No rush, we have a couple of days until the hard freeze still


> > 
> > > ---
> > > v1 -> v2:
> > >   * s/PDRC/CCR/ for clarity and match ICH9 spec
> > >   * remove unnecessary OperationRegion for RCRB
> > > 
> > > v2 -> v3: (no changes)
> > > 
> > > v3 -> v4:
> > >   * quote RCRB description from ICH9 spec to commit log
> > >   * fix indentation issue in _CRS() method declaration
> > >   * create hw/i386/ich9-cc.h for chipset configuration register
> > > values and use them in ASL
> > > 
> > > v4 -> v5:
> > >   * prefix macros in ich9-cc.h with "ICH9_" for better readability
> > > and make use of them in CCR device definition
> > > ---
> > >  hw/i386/q35-acpi-dsdt.dsl     |  16 ++++++++++++++++
> > >  include/hw/i386/ich9-cc.h     |  15 +++++++++++++++
> > >  tests/acpi-test-data/q35/DSDT | Bin 7666 -> 7723 bytes
> > >  3 files changed, 31 insertions(+)
> > >  create mode 100644 include/hw/i386/ich9-cc.h
> > > 
> > > diff --git a/hw/i386/q35-acpi-dsdt.dsl b/hw/i386/q35-acpi-dsdt.dsl
> > > index 16eaca3..8f4bb6a 100644
> > > --- a/hw/i386/q35-acpi-dsdt.dsl
> > > +++ b/hw/i386/q35-acpi-dsdt.dsl
> > > @@ -114,6 +114,22 @@ DefinitionBlock (
> > >          }
> > >      }
> > >  
> > > +#include "hw/i386/ich9-cc.h"
> > > +
> > > +/****************************************************************
> > > + * Chipset Configuration Registers
> > > + ****************************************************************/
> > > +Scope(\_SB.PCI0) {
> > > +    Device (CCR) {
> > > +        Name (_HID, EISAID("PNP0C02"))
> > > +        Name (_UID, 1)
> > > +
> > > +        Name (_CRS, ResourceTemplate() {
> > > +            Memory32Fixed(ReadWrite, ICH9_RCBA_BASE_ADDR,
> > > ICH9_RCRB_SIZE)
> > > +        })
> > > +    }
> > > +}
> > > +
> > >  #include "acpi-dsdt-hpet.dsl"
> > >  
> > >  
> > > diff --git a/include/hw/i386/ich9-cc.h b/include/hw/i386/ich9-cc.h
> > > new file mode 100644
> > > index 0000000..d4918ff
> > > --- /dev/null
> > > +++ b/include/hw/i386/ich9-cc.h
> > > @@ -0,0 +1,15 @@
> > > +/*
> > > + * QEMU ICH9 Chipset Configuration Registers
> > > + *
> > > + * Copyright (c) 2015 Paulo Alcantara <pcacjr@zytor.com>
> > > + *
> > > + * This work is licensed under the terms of the GNU GPL, version 2
> > > or later.
> > > + * See the COPYING file in the top-level directory.
> > > + */
> > > +#ifndef HW_ICH9_CC_H
> > > +#define HW_ICH9_CC_H
> > > +
> > > +#define ICH9_RCBA_BASE_ADDR    0xfed1c000
> > > +#define ICH9_RCRB_SIZE         0x00004000
> > > +
> > > +#endif /* HW_ICH9_CC_H */
> > > diff --git a/tests/acpi-test-data/q35/DSDT
> > > b/tests/acpi-test-data/q35/DSDT index
> > > 4723e5954dccb00995ccaf521b7daf6bf15cf1d4..f3bda7b54ea6d669b1498d9380e7781207fb6e49
> > > 100644 GIT binary patch delta 81
> > > zcmexlz1oJ$CD<iITaJN&F>xbTJfnq$UVN}qe1Nm3L3ERjvvW{9N4$rp3y<Rk9wv_X
> > > lP)`>|j(F#wU_n7HzBWz<Mur0y|1mf)FjO*Z&S3140RVI`6(s-w
> > > 
> > > delta 24
> > > gcmZ2&^U0daCD<k8lPm)R<DrdQ@r;`nF?PxT0Bl$YHUIzs
> > > 
> > > -- 
> > > 2.1.0
> > 
> 
> 
> 
> -- 
> Paulo Alcantara, C.E.S.A.R
> Speaking for myself only.