On Tue, Feb 16, 2021 at 08:45:48AM -0500,
"Michael S. Tsirkin" <m...@redhat.com> wrote:
> On Tue, Feb 16, 2021 at 01:43:01AM -0800, Isaku Yamahata wrote:
> > On Mon, Feb 15, 2021 at 01:48:32PM +0100,
> > Igor Mammedov <imamm...@redhat.com> wrote:
> >
> > > On Fri, 12 Feb 2021 12:51:57 -0800
> > > Isaku Yamahata <isaku.yamah...@gmail.com> wrote:
> > >
> > > > On Fri, Feb 12, 2021 at 04:40:38PM +0100,
> > > > Igor Mammedov <imamm...@redhat.com> wrote:
> > > >
> > > > > On Wed, 10 Feb 2021 22:46:43 -0800
> > > > > Isaku Yamahata <isaku.yamah...@intel.com> wrote:
> > > > >
> > > > > > + Aml *dev;
> > > > > > + Aml *rbuf;
> > > > > > + Aml *resource_template;
> > > > > > + Aml *rbuf_name;
> > > > > > + Aml *crs;
> > > > > > +
> > > > > > + if (!acpi_get_mcfg(&mcfg)) {
> > > > > > + return NULL;
> > > > > > + }
> > > > > > +
> > > > > > + /* DRAM controller */
> > > > > > + dev = aml_device("DRAC");
> > > > > > + aml_append(dev, aml_name_decl("_HID", aml_string("PNP0C01")));
> > > > > > +
> > > > > > + resource_template = aml_resource_template();
> > > > > > + aml_append(resource_template,
> > > > > > + aml_qword_memory(AML_POS_DECODE,
> > > > > > + AML_MIN_FIXED,
> > > > > > + AML_MAX_FIXED,
> > > > > > + AML_NON_CACHEABLE,
> > > > > > + AML_READ_WRITE,
> > > > > > + 0x0000000000000000,
> > > > > > + mcfg.base,
> > > > > > + mcfg.base + mcfg.size - 1,
> > > > > s/mcfg.base + mcfg.size - 1/mcfg.base/
> > > >
> > > > AddressMaximum needs to be the highest address of the region.
> > > > Not base address. By disassemble/assembl it, iasl complains as follows.
> > > > Also there are similar examples in acpi-build.c.
> > > I mostly clean up all places to use the same base address for min/max,
> > > but probably something were left behind.
> > >
> > > spec says:
> > >
> > > acpi 6.3: 19.6.110 QWordMemory
> > >
> > > AddressMaximum evaluates to a 64-bit integer that specifies the highest
> > > possible base address of the
> > > Memory range. The value must have ‘0’ in all bits where the corresponding
> > > bit in AddressGranularity is
> > > ‘1’. For bridge devices which translate addresses, this is the address on
> > > the secondary bus. The 64-bit
> > > field DescriptorName ._MAX is automatically created to refer to this
> > > portion of the resource descriptor.
> >
> > Ok, Linux guest is happy with min=max.
> > I conlude that it's iasl issue.
> >
> > Thanks,
>
> OK but what about all the other places in the code that seem to use this
> field differently?
Igor, what do you think?
The followings are the summary of the situation.
- acpi 6.4: 19.6.110 QWordMemory
_MAX: maximum of base address.
- acpi 6.4: 6.4.3.5 Address Space Resource Descriptors
table 6.44
If _LEN > 0 and _MIF = 1 and _MAF = 1, then _LEN = _MAX - _MIN + 1
This doesn't match with the above description
- iasl
If _LEN > 0 and _MIF = 1 and _MAF = 1,
it emits warning on _LEN != _MAX - _MIN + 1
- Linux Guest MMCONFIG check
check_mcfg_resoure() uses only _MIN. doesn't use _MAX.
_MAX value doesn't matter
- Linux acpi code
acpi_decode_space() uses _MAX to calulate range [start, end], not use _LEN.
i.e. It assumes _LEN = _MAX - _MIN + 1 if _LEN > 0, _MIF = 1, _MAF = 1
- qemu code sets for [qd]word_memory_resource (except this patch)
If _LEN > 0 and _MIF = 1 and _MAF = 1, then set _LEN = _MAX - _MIN + 1
--
Isaku Yamahata <isaku.yamah...@gmail.com>
