Re: [PATCH 6/8] acpi_build: Build IVRS feature report using extended feature register

[Vasant Hegde <vasant.hegde@amd.com>]

On 5/11/2026 6:09 PM, Sairaj Kodilkar wrote:
> Currently IVRS feature report values are hardcoded, this is difficult to
> maintain as any updates to extended feature must be synced. Along with
> it current feature report does not have GATS and HATS set. Hence use
> the extended feature registers to build the IVRS feature report.
> > Signed-off-by: Sairaj Kodilkar <sarunkod@amd.com>
> ---
>  hw/i386/acpi-build.c | 38 +++++++++++++++++++++++++++++++-------
>  hw/i386/acpi-build.h |  1 -
>  2 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 718e3f546b18..82208e06e155 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1747,6 +1747,36 @@ ivrs_host_bridges(Object *obj, void *opaque)
>      return 0;
>  }
>  
> +/*
> + * IVHD type 0x10 reports features using Feature Reporting field, which has
> + * different format than extended feature register (EFR) in the IOMMU MMIO
> + * space.
> + *
> + * Convert the EFR format to feature reporting format.
> + */
> +static uint32_t
> +get_amd_ivhd_feature_report(AMDVIState *s)
> +{
> +    uint64_t feature = amdvi_extended_feature_register(s);
> +    uint32_t is_gt = !!(feature & AMDVI_FEATURE_GT);
> +    uint32_t is_ga = !!(feature & AMDVI_FEATURE_GA);
> +    uint64_t glx_sup = (feature & AMDVI_GLX_SUP_MASK) >> AMDVI_GLX_SUP_SHIFT;
> +    uint64_t hats_mode = (feature & AMDVI_HATS_MODE_MASK) >>
> +                         AMDVI_HATS_MODE_SHIFT;
> +    uint64_t gats_mode = (feature & AMDVI_GATS_MODE_MASK) >>
> +                         AMDVI_GATS_MODE_SHIFT;
> +    uint32_t feature_report;
> +
> +    feature_report = s->xtsup << AMD_IVHD_FEATURE_REPORT_XT_SUP_SHIFT |
> +                     is_gt << AMD_IVHD_FEATURE_REPORT_GT_SUP_SHIFT |
> +                     glx_sup << AMD_IVHD_FEATURE_REPORT_GLX_SUP_SHIFT |

Looks like glx is new? Please drop the glx changes as we are not supporting
guest page table yet.


> +                     is_ga << AMD_IVHD_FEATURE_REPORT_GA_SUP_SHIFT |
> +                     hats_mode << AMD_IVHD_FEATURE_REPORT_HATS_SHIFT |
> +                     gats_mode << AMD_IVHD_FEATURE_REPORT_GATS_SHIFT;
> +
> +    return feature_report;
> +}
> +
>  static void
>  build_amd_iommu(GArray *table_data, BIOSLinker *linker, const char *oem_id,
>                  const char *oem_table_id)
> @@ -1829,13 +1859,7 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker, const char *oem_id,
>      /* IOMMU info */
>      build_append_int_noprefix(table_data, 0, 2);
>      /* IOMMU Feature Reporting */
> -    feature_report = (48UL << 30) | /* HATS   */
> -                     (48UL << 28) | /* GATS   */
> -                     (1UL << 2)   | /* GTSup  */
> -                     (1UL << 6);    /* GASup  */
> -    if (s->xtsup) {
> -        feature_report |= (1UL << 0); /* XTSup */
> -    }
> +    feature_report = get_amd_ivhd_feature_report(s);
>      build_append_int_noprefix(table_data, feature_report, 4);
>  
>      /* IVHD entries as found above */
> diff --git a/hw/i386/acpi-build.h b/hw/i386/acpi-build.h
> index 9fd60a186db1..d81b7890e6e2 100644
> --- a/hw/i386/acpi-build.h
> +++ b/hw/i386/acpi-build.h
> @@ -1,4 +1,3 @@
> -

Unnecessary change.

-Vasant