Re: [RFC PATCH 4/5] hw/acpi/aml-build: add processor hierarchy node structure

From: Andrew Jones <drjones@redhat.com>
To: Ying Fang <fangying1@huawei.com>
Cc: peter.maydell@linaro.org, salil.mehta@huawei.com,
	zhang.zhanghailiang@huawei.com, mst@redhat.com,
	qemu-devel@nongnu.org, shannon.zhaosl@gmail.com,
	Henglong Fan <fanhenglong@huawei.com>,
	alistair.francis@wdc.com, qemu-arm@nongnu.org,
	imammedo@redhat.com
Subject: Re: [RFC PATCH 4/5] hw/acpi/aml-build: add processor hierarchy node structure
Date: Mon, 1 Mar 2021 10:39:19 +0100	[thread overview]
Message-ID: <20210301093919.yt65iz26p6niairw@kamzik.brq.redhat.com> (raw)
In-Reply-To: <5afc6d2b-6e16-d44c-13cf-bd75c63f89db@huawei.com>

On Fri, Feb 26, 2021 at 10:23:03AM +0800, Ying Fang wrote:
> 
> 
> On 2/25/2021 7:47 PM, Andrew Jones wrote:
> > On Thu, Feb 25, 2021 at 04:56:26PM +0800, Ying Fang wrote:
> > > Add the processor hierarchy node structures to build ACPI information
> > > for CPU topology. Since the private resources may be used to describe
> > > cache hierarchy and it is variable among different topology level,
> > > three helpers are introduced to describe the hierarchy.
> > > 
> > > (1) build_socket_hierarchy for socket description
> > > (2) build_processor_hierarchy for processor description
> > > (3) build_smt_hierarchy for thread (logic processor) description
> > > 
> > > Signed-off-by: Ying Fang <fangying1@huawei.com>
> > > Signed-off-by: Henglong Fan <fanhenglong@huawei.com>
> > > ---
> > >   hw/acpi/aml-build.c         | 40 +++++++++++++++++++++++++++++++++++++
> > >   include/hw/acpi/acpi-defs.h | 13 ++++++++++++
> > >   include/hw/acpi/aml-build.h |  7 +++++++
> > >   3 files changed, 60 insertions(+)
> > > 
> > > diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> > > index a2cd7a5830..a0af3e9d73 100644
> > > --- a/hw/acpi/aml-build.c
> > > +++ b/hw/acpi/aml-build.c
> > > @@ -1888,6 +1888,46 @@ void build_slit(GArray *table_data, BIOSLinker *linker, MachineState *ms,
> > >                    table_data->len - slit_start, 1, oem_id, oem_table_id);
> > >   }
> > > +/*
> > > + * ACPI 6.3: 5.2.29.1 Processor hierarchy node structure (Type 0)
> > > + */
> > > +void build_socket_hierarchy(GArray *tbl, uint32_t parent, uint32_t id)
> > > +{
> > > +    build_append_byte(tbl, ACPI_PPTT_TYPE_PROCESSOR); /* Type 0 - processor */
> > > +    build_append_byte(tbl, 20);         /* Length, no private resources */
> > > +    build_append_int_noprefix(tbl, 0, 2);  /* Reserved */
> > > +    build_append_int_noprefix(tbl, ACPI_PPTT_PHYSICAL_PACKAGE, 4);
> > 
> > Missing '/* Flags */'
> 
> Will fix.
> 
> > 
> > > +    build_append_int_noprefix(tbl, parent, 4); /* Parent */
> > > +    build_append_int_noprefix(tbl, id, 4);     /* ACPI processor ID */
> > > +    build_append_int_noprefix(tbl, 0, 4);  /* Number of private resources */
> > > +}
> > > +
> > > +void build_processor_hierarchy(GArray *tbl, uint32_t flags,
> > > +                               uint32_t parent, uint32_t id)
> > > +{
> > > +    build_append_byte(tbl, ACPI_PPTT_TYPE_PROCESSOR);  /* Type 0 - processor */
> > > +    build_append_byte(tbl, 20);         /* Length, no private resources */
> > > +    build_append_int_noprefix(tbl, 0, 2);      /* Reserved */
> > > +    build_append_int_noprefix(tbl, flags, 4);  /* Flags */
> > > +    build_append_int_noprefix(tbl, parent, 4); /* Parent */
> > > +    build_append_int_noprefix(tbl, id, 4);     /* ACPI processor ID */
> > > +    build_append_int_noprefix(tbl, 0, 4);  /* Number of private resources */
> > > +}
> > > +
> > > +void build_thread_hierarchy(GArray *tbl, uint32_t parent, uint32_t id)
> > > +{
> > > +    build_append_byte(tbl, ACPI_PPTT_TYPE_PROCESSOR); /* Type 0 - processor */
> > > +    build_append_byte(tbl, 20);           /* Length, no private resources */
> > > +    build_append_int_noprefix(tbl, 0, 2); /* Reserved */
> > > +    build_append_int_noprefix(tbl,
> > > +                              ACPI_PPTT_ACPI_PROCESSOR_ID_VALID |
> > > +                              ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD |
> > > +                              ACPI_PPTT_ACPI_LEAF_NODE, 4);  /* Flags */
> > > +    build_append_int_noprefix(tbl, parent , 4); /* parent */
> > 
> > 'parent' not capitalized. We want these comments to exactly match the text
> > in the spec.
> 
> Will fix.
> 
> > 
> > > +    build_append_int_noprefix(tbl, id, 4);      /* ACPI processor ID */
> > > +    build_append_int_noprefix(tbl, 0, 4);       /* Num of private resources */
> > > +}
> > > +
> > >   /* build rev1/rev3/rev5.1 FADT */
> > >   void build_fadt(GArray *tbl, BIOSLinker *linker, const AcpiFadtData *f,
> > >                   const char *oem_id, const char *oem_table_id)
> > > diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> > > index cf9f44299c..45e10d886f 100644
> > > --- a/include/hw/acpi/acpi-defs.h
> > > +++ b/include/hw/acpi/acpi-defs.h
> > > @@ -618,4 +618,17 @@ struct AcpiIortRC {
> > >   } QEMU_PACKED;
> > >   typedef struct AcpiIortRC AcpiIortRC;
> > > +enum {
> > > +    ACPI_PPTT_TYPE_PROCESSOR = 0,
> > > +    ACPI_PPTT_TYPE_CACHE,
> > > +    ACPI_PPTT_TYPE_ID,
> > > +    ACPI_PPTT_TYPE_RESERVED
> > > +};
> > > +
> > > +#define ACPI_PPTT_PHYSICAL_PACKAGE          (1)
> > > +#define ACPI_PPTT_ACPI_PROCESSOR_ID_VALID   (1 << 1)
> > > +#define ACPI_PPTT_ACPI_PROCESSOR_IS_THREAD  (1 << 2)      /* ACPI 6.3 */
> > > +#define ACPI_PPTT_ACPI_LEAF_NODE            (1 << 3)      /* ACPI 6.3 */
> > > +#define ACPI_PPTT_ACPI_IDENTICAL            (1 << 4)      /* ACPI 6.3 */
> > > +
> > >   #endif
> > > diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
> > > index 380d3e3924..7f0ca1a198 100644
> > > --- a/include/hw/acpi/aml-build.h
> > > +++ b/include/hw/acpi/aml-build.h
> > > @@ -462,6 +462,13 @@ void build_srat_memory(AcpiSratMemoryAffinity *numamem, uint64_t base,
> > >   void build_slit(GArray *table_data, BIOSLinker *linker, MachineState *ms,
> > >                   const char *oem_id, const char *oem_table_id);
> > > +void build_socket_hierarchy(GArray *tbl, uint32_t parent, uint32_t id);
> > > +
> > > +void build_processor_hierarchy(GArray *tbl, uint32_t flags,
> > > +                               uint32_t parent, uint32_t id);
> > > +
> > > +void build_thread_hierarchy(GArray *tbl, uint32_t parent, uint32_t id);
> > 
> > Why does build_processor_hierarchy() take a flags argument, but the
> > others don't? Why not just have a single 'flags' taking function,
> > like [*] that works for all of them? I think that answer to that is
> 
> Yes, you are right.
> 
> > that when cache topology support is added it's better to break these
> > into separate functions, but should we do that now? It seems odd to
> > be introducing unused defines and this API before it's necessary.
> So it is better for us to keep just one common build_processor_hierarchy
> API here in your opinion.

Well, a consistent API without unused defines. Whether or not that's
a single common function or not isn't that important.

Thanks,
drew

> 
> > 
> > [*] https://github.com/rhdrjones/qemu/commit/439b38d67ca1f2cbfa5b9892a822b651ebd05c11
> > 
> > Thanks,
> > drew
> > 
> > > +
> > >   void build_fadt(GArray *tbl, BIOSLinker *linker, const AcpiFadtData *f,
> > >                   const char *oem_id, const char *oem_table_id);
> > > -- 
> > > 2.23.0
> > > 
> > > 
> > 
> > .
> > 
> 
> Thanks,
> Ying.
> 