Re: [PATCH v2 2/3] hw/cxl: Add QTG _DSM support for ACPI0017 device

[Michael S. Tsirkin]

On Mon, Sep 04, 2023 at 05:18:46PM +0100, Jonathan Cameron wrote:
> From: Dave Jiang <dave.jiang@intel.com>
> 
> Add a simple _DSM call support for the ACPI0017 device to return a fake QTG
> ID value of 0 in all cases. The enabling is for _DSM plumbing testing
> from the OS.
> 
> Following edited for readbility only
> 
> Device (CXLM)
> {
>     Name (_HID, "ACPI0017")  // _HID: Hardware ID
> ...
>     Method (_DSM, 4, Serialized)  // _DSM: Device-Specific Method
>     {
>         If ((Arg0 == ToUUID ("f365f9a6-a7de-4071-a66a-b40c0b4f8e52")))
>         {
>             If ((Arg2 == Zero))
>             {
>                 Return (Buffer (One) { 0x01 })
>             }
> 
>             If ((Arg2 == One))
>             {
>                 Return (Package (0x02)
>                 {
>                     Buffer (0x02)
>                     { 0x01, 0x00 },
>                     Package (0x01)
>                     {
>                         Buffer (0x02)
>                         { 0x00, 0x00 }
>                     }
>                 })
>             }
>         }
>     }
> 
> Signed-off-by: Dave Jiang <dave.jiang@intel.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 
> --
> v2: Minor edit to drop reference to switches in patch description.
> ---

>  include/hw/acpi/cxl.h |  1 +
>  hw/acpi/cxl.c         | 57 +++++++++++++++++++++++++++++++++++++++++++
>  hw/i386/acpi-build.c  |  1 +
>  3 files changed, 59 insertions(+)


This is not the right way to format it. The correct way is:

---
v2: Minor edit to drop reference to switches in patch description.

 include/hw/acpi/cxl.h |  1 +
 hw/acpi/cxl.c         | 57 +++++++++++++++++++++++++++++++++++++++++++
 hw/i386/acpi-build.c  |  1 +
 3 files changed, 59 insertions(+)

The way you do it breaks b4 and a bunch of other tools.  signatures must
come last before ---, then versioning info (which generally does not
need to be in git because readers of git have no access to older
versions, though there could be exceptions. If there's anything relevant
in this versioning history, such as some design directions which were
tried and discarded, then put it above ---). Then the diff.


> 
> diff --git a/include/hw/acpi/cxl.h b/include/hw/acpi/cxl.h
> index acf4418886..8f22c71530 100644
> --- a/include/hw/acpi/cxl.h
> +++ b/include/hw/acpi/cxl.h
> @@ -25,5 +25,6 @@ void cxl_build_cedt(GArray *table_offsets, GArray 
> *table_data,
>                      BIOSLinker *linker, const char *oem_id,
>                      const char *oem_table_id, CXLState *cxl_state);
>  void build_cxl_osc_method(Aml *dev);
> +void build_cxl_dsm_method(Aml *dev);
>  
>  #endif
> diff --git a/hw/acpi/cxl.c b/hw/acpi/cxl.c
> index 92b46bc932..5e9039785a 100644
> --- a/hw/acpi/cxl.c
> +++ b/hw/acpi/cxl.c
> @@ -30,6 +30,63 @@
>  #include "qapi/error.h"
>  #include "qemu/uuid.h"
>  
> +void build_cxl_dsm_method(Aml *dev)
> +{
> +    Aml *method, *ifctx, *ifctx2;
> +
> +    method = aml_method("_DSM", 4, AML_SERIALIZED);
> +    {
> +        Aml *function, *uuid;
> +
> +        uuid = aml_arg(0);
> +        function = aml_arg(2);
> +        /* CXL spec v3.0 9.17.3.1 *, QTG ID _DSM */
> +        ifctx = aml_if(aml_equal(
> +            uuid, aml_touuid("F365F9A6-A7DE-4071-A66A-B40C0B4F8E52")));
> +
> +        /* Function 0, standard DSM query function */
> +        ifctx2 = aml_if(aml_equal(function, aml_int(0)));
> +        {
> +            uint8_t byte_list[1] = { 0x01 }; /* functions 1 only */
> +
> +            aml_append(ifctx2,
> +                       aml_return(aml_buffer(sizeof(byte_list), byte_list)));
> +        }
> +        aml_append(ifctx, ifctx2);
> +
> +        /*
> +         * Function 1
> +         * A return value of {1, {0}} inciate that
> +         * max supported QTG ID of 1 and recommended QTG is 0.
> +         * The values here are faked to simplify emulation.
> +         */
> +        ifctx2 = aml_if(aml_equal(function, aml_int(1)));
> +        {
> +            uint16_t word_list[1] = { 0x01 };
> +            uint16_t word_list2[1] = { 0 };
> +            uint8_t *byte_list = (uint8_t *)word_list;
> +            uint8_t *byte_list2 = (uint8_t *)word_list2;
> +            Aml *pak, *pak1;
> +
> +            /*
> +             * The return package is a package of a WORD and another package.
> +             * The embedded package contains 0 or more WORDs for the
> +             * recommended QTG IDs.
> +             */
> +            pak1 = aml_package(1);
> +            aml_append(pak1, aml_buffer(sizeof(uint16_t), byte_list2));
> +            pak = aml_package(2);
> +            aml_append(pak, aml_buffer(sizeof(uint16_t), byte_list));
> +            aml_append(pak, pak1);
> +
> +            aml_append(ifctx2, aml_return(pak));
> +        }
> +        aml_append(ifctx, ifctx2);
> +    }
> +    aml_append(method, ifctx);
> +    aml_append(dev, method);
> +}
> +
>  static void cedt_build_chbs(GArray *table_data, PXBCXLDev *cxl)
>  {
>      PXBDev *pxb = PXB_DEV(cxl);
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index bb12b0ad43..d3bc5875eb 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1422,6 +1422,7 @@ static void build_acpi0017(Aml *table)
>      method = aml_method("_STA", 0, AML_NOTSERIALIZED);
>      aml_append(method, aml_return(aml_int(0x01)));
>      aml_append(dev, method);
> +    build_cxl_dsm_method(dev);
>  
>      aml_append(scope, dev);
>      aml_append(table, scope);
> -- 
> 2.39.2