Re: [PATCH v5 18/20] intel_iommu: Introduce a property x-flts for scalable modern mode

[Jason Wang]

On Mon, Nov 11, 2024 at 4:39 PM Zhenzhong Duan <zhenzhong.duan@intel.com> wrote:
>
> Intel VT-d 3.0 introduces scalable mode, and it has a bunch of capabilities
> related to scalable mode translation, thus there are multiple combinations.
>
> This vIOMMU implementation wants to simplify it with a new property "x-flts".
> When enabled in scalable mode, first stage translation also known as scalable
> modern mode is supported. When enabled in legacy mode, throw out error.
>
> With scalable modern mode exposed to user, also accurate the pasid entry
> check in vtd_pe_type_check().
>
> Suggested-by: Jason Wang <jasowang@redhat.com>
> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
> ---
>  hw/i386/intel_iommu_internal.h |  2 ++
>  hw/i386/intel_iommu.c          | 28 +++++++++++++++++++---------
>  2 files changed, 21 insertions(+), 9 deletions(-)
>
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 2c977aa7da..e8b211e8b0 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -195,6 +195,7 @@
>  #define VTD_ECAP_PASID              (1ULL << 40)
>  #define VTD_ECAP_SMTS               (1ULL << 43)
>  #define VTD_ECAP_SLTS               (1ULL << 46)
> +#define VTD_ECAP_FLTS               (1ULL << 47)
>
>  /* CAP_REG */
>  /* (offset >> 4) << 24 */
> @@ -211,6 +212,7 @@
>  #define VTD_CAP_SLLPS               ((1ULL << 34) | (1ULL << 35))
>  #define VTD_CAP_DRAIN_WRITE         (1ULL << 54)
>  #define VTD_CAP_DRAIN_READ          (1ULL << 55)
> +#define VTD_CAP_FS1GP               (1ULL << 56)
>  #define VTD_CAP_DRAIN               (VTD_CAP_DRAIN_READ | 
> VTD_CAP_DRAIN_WRITE)
>  #define VTD_CAP_CM                  (1ULL << 7)
>  #define VTD_PASID_ID_SHIFT          20
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index b921793c3a..a7a81aebee 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -803,16 +803,18 @@ static inline bool 
> vtd_is_fl_level_supported(IntelIOMMUState *s, uint32_t level)
>  }
>
>  /* Return true if check passed, otherwise false */
> -static inline bool vtd_pe_type_check(X86IOMMUState *x86_iommu,
> -                                     VTDPASIDEntry *pe)
> +static inline bool vtd_pe_type_check(IntelIOMMUState *s, VTDPASIDEntry *pe)
>  {
>      switch (VTD_PE_GET_TYPE(pe)) {
> -    case VTD_SM_PASID_ENTRY_SLT:
> -        return true;
> -    case VTD_SM_PASID_ENTRY_PT:
> -        return x86_iommu->pt_supported;
>      case VTD_SM_PASID_ENTRY_FLT:
> +        return !!(s->ecap & VTD_ECAP_FLTS);
> +    case VTD_SM_PASID_ENTRY_SLT:
> +        return !!(s->ecap & VTD_ECAP_SLTS);
>      case VTD_SM_PASID_ENTRY_NESTED:
> +        /* Not support NESTED page table type yet */
> +        return false;
> +    case VTD_SM_PASID_ENTRY_PT:
> +        return !!(s->ecap & VTD_ECAP_PT);
>      default:
>          /* Unknown type */
>          return false;
> @@ -861,7 +863,6 @@ static int vtd_get_pe_in_pasid_leaf_table(IntelIOMMUState 
> *s,
>      uint8_t pgtt;
>      uint32_t index;
>      dma_addr_t entry_size;
> -    X86IOMMUState *x86_iommu = X86_IOMMU_DEVICE(s);
>
>      index = VTD_PASID_TABLE_INDEX(pasid);
>      entry_size = VTD_PASID_ENTRY_SIZE;
> @@ -875,7 +876,7 @@ static int vtd_get_pe_in_pasid_leaf_table(IntelIOMMUState 
> *s,
>      }
>
>      /* Do translation type check */
> -    if (!vtd_pe_type_check(x86_iommu, pe)) {
> +    if (!vtd_pe_type_check(s, pe)) {
>          return -VTD_FR_PASID_TABLE_ENTRY_INV;
>      }
>
> @@ -3827,6 +3828,7 @@ static Property vtd_properties[] = {
>                        VTD_HOST_ADDRESS_WIDTH),
>      DEFINE_PROP_BOOL("caching-mode", IntelIOMMUState, caching_mode, FALSE),
>      DEFINE_PROP_BOOL("x-scalable-mode", IntelIOMMUState, scalable_mode, 
> FALSE),
> +    DEFINE_PROP_BOOL("x-flts", IntelIOMMUState, scalable_modern, FALSE),
>      DEFINE_PROP_BOOL("snoop-control", IntelIOMMUState, snoop_control, false),
>      DEFINE_PROP_BOOL("x-pasid-mode", IntelIOMMUState, pasid, false),
>      DEFINE_PROP_BOOL("dma-drain", IntelIOMMUState, dma_drain, true),
> @@ -4558,7 +4560,10 @@ static void vtd_cap_init(IntelIOMMUState *s)
>      }
>
>      /* TODO: read cap/ecap from host to decide which cap to be exposed. */
> -    if (s->scalable_mode) {
> +    if (s->scalable_modern) {
> +        s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_FLTS;
> +        s->cap |= VTD_CAP_FS1GP;
> +    } else if (s->scalable_mode) {
>          s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS;
>      }
>
> @@ -4737,6 +4742,11 @@ static bool vtd_decide_config(IntelIOMMUState *s, 
> Error **errp)
>          }
>      }
>
> +    if (!s->scalable_mode && s->scalable_modern) {
> +        error_setg(errp, "Legacy mode: not support x-flts=on");

This seems to be wired, should we say "scalable mode is needed for
scalable modern mode"?

> +        return false;
> +    }
> +
>      if (!s->scalable_modern && s->aw_bits != VTD_HOST_AW_39BIT &&
>          s->aw_bits != VTD_HOST_AW_48BIT) {
>          error_setg(errp, "%s mode: supported values for aw-bits are: %d, %d",
> --
> 2.34.1
>

Thanks