Re: [RFC v3 13/25] intel_iommu: modify x-scalable-mode to be string option

[Peter Xu <peterx@redhat.com>]

On Wed, Jan 29, 2020 at 04:16:44AM -0800, Liu, Yi L wrote:
> From: Liu Yi L <yi.l.liu@intel.com>
> 
> 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.
> While this vIOMMU implementation wants simplify it for user by providing
> typical combinations. User could config it by "x-scalable-mode" option. The
> usage is as below:
> 
> "-device intel-iommu,x-scalable-mode=["legacy"|"modern"]"

Maybe also "off" when someone wants to explicitly disable it?

> 
>  - "legacy": gives support for SL page table
>  - "modern": gives support for FL page table, pasid, virtual command
>  -  if not configured, means no scalable mode support, if not proper
>     configured, will throw error
> 
> Cc: Kevin Tian <kevin.tian@intel.com>
> Cc: Jacob Pan <jacob.jun.pan@linux.intel.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Yi Sun <yi.y.sun@linux.intel.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Eduardo Habkost <ehabkost@redhat.com>
> Signed-off-by: Liu Yi L <yi.l.liu@intel.com>
> Signed-off-by: Yi Sun <yi.y.sun@linux.intel.com>
> ---
>  hw/i386/intel_iommu.c          | 27 +++++++++++++++++++++++++--
>  hw/i386/intel_iommu_internal.h |  3 +++
>  include/hw/i386/intel_iommu.h  |  2 ++
>  3 files changed, 30 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c
> index 1c1eb7f..33be40c 100644
> --- a/hw/i386/intel_iommu.c
> +++ b/hw/i386/intel_iommu.c
> @@ -3078,7 +3078,7 @@ static Property vtd_properties[] = {
>      DEFINE_PROP_UINT8("aw-bits", IntelIOMMUState, aw_bits,
>                        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_STRING("x-scalable-mode", IntelIOMMUState, scalable_mode_str),
>      DEFINE_PROP_BOOL("dma-drain", IntelIOMMUState, dma_drain, true),
>      DEFINE_PROP_END_OF_LIST(),
>  };
> @@ -3708,8 +3708,11 @@ static void vtd_init(IntelIOMMUState *s)
>      }
>  
>      /* TODO: read cap/ecap from host to decide which cap to be exposed. */
> -    if (s->scalable_mode) {
> +    if (s->scalable_mode && !s->scalable_modern) {
>          s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_SLTS;
> +    } else if (s->scalable_mode && s->scalable_modern) {
> +        s->ecap |= VTD_ECAP_SMTS | VTD_ECAP_SRS | VTD_ECAP_PASID
> +                   | VTD_ECAP_FLTS | VTD_ECAP_PSS;

This patch might be good to be the last one after all the impls are
ready.

>      }
>  
>      vtd_reset_caches(s);
> @@ -3845,6 +3848,26 @@ static bool vtd_decide_config(IntelIOMMUState *s, Error **errp)
>          return false;
>      }
>  
> +    if (s->scalable_mode_str &&
> +        (strcmp(s->scalable_mode_str, "modern") &&
> +         strcmp(s->scalable_mode_str, "legacy"))) {
> +        error_setg(errp, "Invalid x-scalable-mode config");

Maybe "..., Please use 'modern', 'legacy', or 'off'." to show options.

> +        return false;
> +    }
> +
> +    if (s->scalable_mode_str &&
> +        !strcmp(s->scalable_mode_str, "legacy")) {
> +        s->scalable_mode = true;
> +        s->scalable_modern = false;
> +    } else if (s->scalable_mode_str &&
> +        !strcmp(s->scalable_mode_str, "modern")) {
> +        s->scalable_mode = true;
> +        s->scalable_modern = true;
> +    } else {
> +        s->scalable_mode = false;
> +        s->scalable_modern = false;
> +    }
> +
>      return true;
>  }
>  
> diff --git a/hw/i386/intel_iommu_internal.h b/hw/i386/intel_iommu_internal.h
> index 862033e..c4dbb2c 100644
> --- a/hw/i386/intel_iommu_internal.h
> +++ b/hw/i386/intel_iommu_internal.h
> @@ -190,8 +190,11 @@
>  #define VTD_ECAP_PT                 (1ULL << 6)
>  #define VTD_ECAP_MHMV               (15ULL << 20)
>  #define VTD_ECAP_SRS                (1ULL << 31)
> +#define VTD_ECAP_PSS                (19ULL << 35)
> +#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 */
> diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
> index 8571a85..1ef2917 100644
> --- a/include/hw/i386/intel_iommu.h
> +++ b/include/hw/i386/intel_iommu.h
> @@ -244,6 +244,8 @@ struct IntelIOMMUState {
>  
>      bool caching_mode;              /* RO - is cap CM enabled? */
>      bool scalable_mode;             /* RO - is Scalable Mode supported? */
> +    char *scalable_mode_str;        /* RO - admin's Scalable Mode config */
> +    bool scalable_modern;           /* RO - is modern SM supported? */
>  
>      dma_addr_t root;                /* Current root table pointer */
>      bool root_scalable;             /* Type of root table (scalable or not) */
> -- 
> 2.7.4
> 

-- 
Peter Xu