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

[Fan Ni <fan.ni@samsung.com>]

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>

Looks good to me. One minor comment inline.
> 
> --
> 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(+)
> 
> 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)

Not a concern for now, I think, do we need to check the revision
field?

Fan
> +{
> +    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
> 
>